How

With four key factors affecting cable assembly performance—mechanical, electrical, environmental, and application-specific—manufacturers must ensure that cable assemblies can withstand harsh conditions and operate reliably over the system’s life.

Cable assemblies with durable, compact, and flexible designs help that, whether used in systems operating on land, subsurface, sea, or space.

However, as applications vary, so do the design and cable assembly types. Today, we’ll take a closer look at some of them.

What is a Cable Assembly?

A cable assembly is designed to consolidate the functionality of multiple cables into a single, more manageable unit, making it simpler to set up, move, and repair.

Many wires and cables are color-coded or labeled for quick identification.

The wires in certain cable assemblies are exposed, whereas those in others are completely covered.

A cable assembly typically has a single component connecting each end and plugging into an outlet.

While the final assembly may be concealed, it is usually constructed so that the individual components can be seen for at least a few inches before joining the part plugging into the power source.

Cable assemblies simplify designing, buying, testing, and installing cables.

They cut costs and streamline supply networks.

Optional electronic components and features like bend reliefs and sealing caps can make them active while providing flexibility and lightweight benefits.

Common Application of Cable Assemblies in Specific Industry

Transmission of either information or electricity is the usual function of an assembly.

Usually, you can see them in the following industries.

Automotive

Most manufacturers provide a variety of automotive sectors program requirements, such as automation grade cables, assessment submissions, and a lengthy development cycle.

It is common practice for manufacturers of custom wire harnesses to demand either an SAE-approved or special dust and waterproof caps and connectors.

Hence, you will use silicone seals, gaskets, and bespoke over-molds and grommets in automotive cables.

Medical

Multiple types of cables carry electricity and high-definition video between medical devices.

Sterilization, bio-compatibility, and ISO 13485 certifications are all prerequisites for many medical cables.

Many wire-sleeve and over-mold methods exist because of their resistance to ethylene oxide, autoclave sterilization, and isopropyl alcohol.

MilSpec

Mil-spec standard 38999 is a comprehensive standard for electrical harnesses for military applications.

Moreover, manufacturers offer expert designs for these cables, which often have mil-hardened parts.

You need intricate connector systems and specialized materials for the wire jackets to put together several of these cables.

Connector systems that adhere to Mil-spec 38999 typically call for specialized tools.

For example, insert/extract tooling, back shell torque wrenches, HIPOT test equipment, crimpers, and multimeters to achieve the program’s goals.

Military-grade cable assemblies are typically used for aerospace, tactical, and marine applications. 

Caption: Wire processing for connecting machine

7 Types of Cable Assemblies You May Need

The various cable assembly types may be grouped by application, the number of wires (core), desired shape, and material, including complex military, multi-conductor, round coaxial/RF, wire and cable harnesses, flat ribbon, custom electro-mechanical, and more.

Data & Video Cables- D-Sub, USB, HMDI, DisplayPort

Multiple variations within each family are just some of the industry standard cable formats manufacturers support.

This applies to the male and female varieties, the full-sized and miniaturized forms, the “A,” “B,” and “C” varieties of the USB connector, RJ45, RJ11, and other Ethernet cable and phone jack types.

Power Cables

Power cables can employ various cable technologies for general usage and normally run at voltages lower than 30VDC or 120VAC.

You might use PVC coatings, tinned copper wires, thermoplastic over-molds, and connectors in manufacturing these cables.

For several common connector types, such as DC power barrels and AC power plugs like NEMA 5-15P and 5-15/20, in-house tooling is available.

Low Voltage Hook-Up Wire Harnesses

A wide range of wire harness constructions meet UL and industry standards and need 300VDC or less.

Companies can offer solutions for single-wire and multi-wire cross-sections with 1 to 100 conductors.

You can find these wire harnesses inside consumer devices, mechanical systems, medical equipment, and most of our daily tech.

RF/EMI Cable Assemblies

The world is already very noisy, and each of your cables undoubtedly contributes to that.

If there is interference in the radio spectrum, we call it RFI or radio frequency interference.

There are EMI or electromagnetic interferences as well.

However, if the disturbance persists, the circuit’s performance may suffer or stop working altogether.

Any data path may suffer consequences, from a rise in failure rate to complete data loss.

Depending on the context, you may wish to use these signals.

Hence, you should consult with the cable assembly person to determine the optimal course of action.

Molded Cable Assemblies

You have likely encountered molded cable assemblies outside of your professional life.

In most cases, manufacturers might prefabricate the HDMI cables in a mold.

A molded cable assembly might be the best option if your application demands increased durability and a cleaner look.

You can also use plastic or metal to create shells; both types, protected and uncovered, have their uses.

Assembled Coaxial Round

Coaxial cables are special electrical wires in which the inner conductor is encased in an insulating tube, and the outer conductor is encased in a shielding tube.

A jacket is typically around the outside of a coaxial wire to provide insulation.

The word “coaxial” refers to the core conductor and the external shield lying along the same geometric axis.

Coax cables have several uses in vehicles, airplanes, medical devices, and radios.

Flat Ribbon Cable Assemblies

Ribbon cables that are flat and sleek are awesome.

The cables are neatly arranged in a flat ribbon rather than packed together within a sheath.

Ribbon cables, which you have probably seen in old computers, are flat cable assemblies that are just as functional as round cables.

However, they can be more useful in some situations due to their smaller footprint.

Ribbon cables make viewing and classifying each wire easy and can have color-coding to indicate their function.

Moreover, their primary use is bulk termination at IDC connectors with a sharp forked row of contacts.

In some cases, ribbon cable assemblies are superior to round cable assemblies when the cable’s width is a critical design factor.

Caption: Bare wire stranded

Cable Assembly Design Considerations

You need to follow some key considerations before designing the system.

• Identify the requirements and application area so that you design the protection accordingly.
• Determine the correct length and size of the conductor
• Also, determine the proper conductor and insulation material for your wires
• See that the cables are flexible enough to endure the abrasions
• Decide the stranding pattern of the cable so that it offers good flexibility
• Moreover, determine the correct shielding and plating types of the conductors so that they work in humid environments
• In the end, use the correct connector types and termination methods.

Caption: Power connector

Conclusion

Cable assemblies play a significant role in the manufacture of any system.

Also, there are many types for each industry type.

Thus, designing these harnesses requires extra care and consideration to work perfectly.

Here at Cloom, we offer wiring harness and cable assembly solutions, so you don’t have to worry about perfection.

Your vehicle battery can die for several reasons, like low temperature. You must start your car to drive it to the mechanic’s shop. You may need a booster cable assembly to jump-start the battery.

What is a booster cable?

You can call a booster cable a jump lead or a jumper cable. This cable comprises a pair of insulated wires with alligator clips at both ends so it can interconnect the non-functioning equipment or vehicle to some auxiliary source. The auxiliary can be another vehicle, equipment with the same voltage system, or another battery.

The alligator chips in the wires have proper insulation to avoid short circuits. These clips are either made of copper or steel, and these chips have polarity markings in black (-) and red (+) colors. You will find one black and one red cable in a booster assembly. The colors help you to know where to attach the cables. In an electrical system, electric current flows from a negative terminal to a positive terminal through some wires to power something. In this case, they will power the car’s starter.

Thus, you must connect the correct terminals to make your jumper cable work properly. Always connect the red cable with the positive terminal and the black cable with the negative terminal. Remember not to touch the jumper cable to anything except the target.

Battery jumper cables

Booster cable assembly considerations

When choosing a booster cable to work with your car, consider the following features.

Jumper cable gauge

Generally, jumper cables range from gauge 1 to gauge 12. According to this scale, Gauge 1 is a heavy-duty option, while the last one, i.e., gauge 12, is a light-duty option. 

As you know, thick cables carry more current; you can jump-start a battery faster with a thicker cable.

• According to the industry recommendations, you must use a 4-gauge jumper cable for a dead battery.
• However, to jump-start a drained battery in normal temperatures, you can use a 10-gauge cable. Of course, most of the time, we choose the gauge according to vehicle types.
• For cars, gauge 6 is enough; for bikes, you can do it with a gauge-10 wire as bikes do not need more power, and a smaller gauge is enough.
• If you have a full-size or diesel truck, it is better to take the gauge-4 wire.
• Apart from this, if you are handling something heavier than a truck with a couple of batteries, you can use gauge-1 or gauge-2.

Length

If two cars face each other, a 10 feet long cable is enough, but that is not always possible. So always go to longer lengths for higher flexibility. Remember, as the cable length increases, the gauge decreases as less charge flows through the longer lengths.

Insulation

When you use a jumper cable in cold climatic conditions, you need an adequately insulated set of jumper cables; otherwise, the cables will break when you take them out. In addition, insulation helps in preventing general wear and tear. If the cable gets damaged, it results in an arc formation, which can shock you or your car.

Clip material

The auxiliary clips on the jumper cable act as a clamp to ensure a solid connection to the battery. In the copper-plated clamps, the base metal is steel which is not a good conductor of electricity. In addition, these clamps start wearing off over time, making loose connections. On the other hand, even if the copper clamps scratch, they will continue working efficiently. 

Amperage

Starting a smaller car needs less amperage than starting a large truck or an SUV vehicle.

• Generally speaking, 200 amperes is enough to provide the necessary power.
• However, the industry recommends using not less than 400 amperes of cables.
• You may need jumper cables with more than 600 amps for some very heavy vehicles.

Warranty

Always pick a jumper cable that covers a warranty and is UL certified. With such safety certificates, the company is there to help if anything goes wrong.

High-quality jumper cables

Safety tips for jumping start a car.

• Read your car’s manual and look for specific car batteries or jump-start instructions. Some manufacturers suggest not to jump-start your car, while others give particular instructions to jump-start the car.
• Look for the car battery. Most of the time, it is in the front portion, under the hood. However, in some car models, you may also find the battery in the trunk. If the battery’s location is in the trunk, find its designated terminals for use. 
• Take note of the battery’s positive and negative terminals and ensure that you attach the jumper cables to the correct terminals to avoid accidents.
• For the safer side, remove the keys from the car’s ignition (both cars if using the car for a jump start).
• Make sure that nothing flammable is available near the battery. There are chances of sparks, fires, and explosions during jump start. The car batteries and portable jump devices have high voltages.

Jumpstart a car

How To Jump Start a Car

There are two ways of jump-starting a dead battery: a portable jump battery or another vehicle.

Use jumper cables with another car.

• Firstly, find out the location of the battery. Mostly, the battery is with the engine.
• Secondly, park both cars close enough but without touching each other from anywhere; otherwise, the current will flow through different parts along with jumper cables.
• Power off the engine of both cars. 
• Note the battery’s positive (+) and negative (-) terminals and attach the jumper cable to the proper terminals. 
• First, connect one side of the red jumper cable to the non-working battery’s positive terminal.
• Secondly, connect the other end of the red cable to the positive terminal of the live car battery.
• Third, attach one end of the back jumper cable to the negative terminal of the working car’s battery.
• Finally, connect another end of the black cable to a piece of stationery metal on the car with the dead battery.
• Remember not to join this terminal to the negative terminal of the non-working car’s battery.
• Why? Some people consider it okay, but it increases the chances of fire and explosion if the jump start fails.
• You can connect that part to the engine bolt, car’s chassis, alternator bracket, or a grounding terminal. 

• When you finish all the connections, charging begins, and your vehicle may either start immediately or take some time.
• Give some time for the engine to work and let current flow from the working battery to the dead battery.
• After some time, try to start the car. Insert the key and turn it to start. Hold the key only for a few seconds and not more than that.
• You may need to do this several times.
• If your jump-start does work well, the engine will start. Once you drive the car for some time, it will automatically recharge the battery.
• If you hear the engine cranking on turning the key, there may be another issue, and you may need to see the mechanic.
• It would help to disconnect the jumper cables when your dead battery starts working. Ensure not to touch the cables to anything before you make all disconnections; otherwise, the current can go to some unwanted locations.
• First, detach the black cable from the car’s chassis/bolt/terminal.
• Second, detach another end of the black jumper cable from the negative terminal of the working car’s battery.
• Third, detach the end of the red jumper cable from the working car’s battery’s positive terminal.
• Finally, disconnecting its other end from the car’s battery’s positive terminal requires a jump start.

Jump-start a car with another car

Use a portable jump starter.

• You can also use portable jump starters/jump boxes or battery packs to jump-start your car if another car is unavailable.
• As it is portable, you can keep it in the trunk, glove box, or anywhere else. However, most jump starters cannot bear very high summer temperatures.
• So, read the instructions before you carry one into your car.
• Switch off the starter. Also, ensure that all auxiliary features of your dead vehicle are off.
• The portable jump devices have two clamps attached permanently to the tool.
• These include one positive red clamp and another negative black clamp.
• Try to keep them away to avoid any sparking.
• Next, connect the red jumper cable clamp to the dead battery’s positive terminal and the black clamp to the ground or car’s chassis.
• When you have made proper connections, switch on the power of the jump starter. Try to start the vehicle by turning the key to start.
• Hold for a few seconds. If the car does not start, allow the battery to cool for a few seconds before you make another attempt.
• Now try again. If your jump-start is working, your engine must start, let it run for a few seconds, and it will charge the battery automatically.

• Now, disconnect the jump starter cables.
• First, disconnect the negative black cable from the car and remove the red cable from the car’s battery terminal. 
• If your engine does not turn over even after trying a couple of times, you may have another problem at hand; let an experienced mechanic take a look at your car and find the real reason. 

Jump start a car with portable jump starters

Choose jumper cables by vehicle type.

It doesn’t matter if you have enough knowledge about jumper cables. The following can still help you get one.

Compact

You can start a compact car with a 6-gauge jumper cable. So, if you have a Kia forte or Mazda 3, you will need a 10 feet gauge-6 cable that can give 200 amps of current. However, we suggest you still use a gauge-4 cable 20 feet long. Also, look for the cable that can provide 400 amps for safe and best results.

Sports cars

For fast sports cars, a 4-gauge 10 feet cable won’t do the work. You will at least need a 2-gauge 20-foot-long jumper cable. Although 400 amps are okay for sports cars, it would be good to choose 600 amps. Also, pick the jumper cables having clamps of solid copper for a safe and secure connection. 

Intermediate

For intermediate cars like Toyota Camry or Kia K5, you need a 6-gauge 10-foot jumper cable that provides 200 amps. However, to ensure uninterrupted performance, you must go for a gauge 4 20 feet jumper cable supplying 400 amps.

Full-size

For full-size sedans, you need a minimum of gauge-6 10 feet jumper cable, which can supply 200 amps of power. For maximum performance, choose a jumper cable that is 4 gauge 20 feet long. It will be much better if the cable can provide 800 amps of power.

SUV/minivan:

For SUVs like Honda Passport, you need extra power to jump start. Choose a 4-gauge, 10 feet-long jumper cable supplying 400 amps of power. You can also take a 2-gauge, 20-feet long jumper cable with 800 amps of power for better results.

Van/Truck:

If you own a full-size van like Chevy Express, you need a 4-gauge, 10 feet-long jumper cable with 400-amp power to get your ride back on the road. Further, a 2-gauge, 20-feet long jumper cable supplying 800 amps of power is more reliable, and such cables do not create any problems while jump-starting large vehicles of this size.

Battery Jumper Cable Assembly Product Details

Conclusion

People usually do not keep their jump starters charged; however, it is essential. Otherwise, you will need another car to bring your dead battery back to life. Nevertheless, you will surely need a pair of jumper cables. Wiringo suggests you get 4–6 gauge cables 20 feet or 6 meters long.

Electrical harnesses are a staple in modern electronics and the backbone of the auto industry.

Without it, the systems inside these machines wouldn’t be automatic.

However, technical progress has allowed the use of adaptable and robust wire harnesses useful in other complex industries, like the aerospace or aviation industry.

Let’s see how the aircraft wire harness evolved during the period and how they are used now.

Innovations in Aircraft Technology 

Flying in today’s high-tech world may seem like a mundane experience, something that most of us experienced before.

However, airplane technology has progressed a lot thanks to its rich history.

When planes first took to the skies, aerodynamics was the key to getting from point A to point B.

Thermal airships, or hot air balloons, were the first aircraft to carry humans.

However, aerodynamics and motor technology advancements in the early 20th century made powered-controlled flights increasingly common.

Similar to modern airplanes, these early models were developed by 1909.

Aerospace engineering has advanced through the years, with more potent aircraft engines and new improvements in aircraft wiring harnesses.

Aircraft and the aviation sector, as it exists now, would not exist without the technological breakthroughs it has experienced.

At the same time, an aircraft wire harness serves the same primary function as any other wiring system and the innovations it has brought to the aerospace industry.

Caption: Hydraulic lines inside the aviation system

Why Do Aircraft Have Wiring Harnesses?

There was no such thing as a wiring harness in the early days of airplane development since electrical systems did not exist.

They had to move the flying control surfaces using only structural parts, ropes, and pulleys.

Metal cables soon replaced the ropes; even today, many planes don’t “fly by wire,” instead relying on cables and pulleys.

Eventually, an airplane designer decided to wire in a light and put in a switch, battery, and bulb.

He connected these parts with cables, creating the airplane’s first electrical lighting system.

Since this system only required a small number of wires, harness manufacturers put them individually in safe locations.

Subsequently, other architects came along and incorporated even more electrical infrastructures.

Aircraft mechanics eventually realized that they were installing cables one at a time despite groups of wires flowing from one part to another.

Moreover, they needed more wires for each additional device.

The duration of this setup process was lengthy.

Mechanics began grouping and routing cables together in bundles to increase productivity.

The aviation industry took notice and deemed this a worthwhile development.

After conceptualizing the wire bundles as a whole, they assembled them there.

With this, they created the first wire harness.

Aircraft wire harnesses serve this purpose.

Caption: Shot wire tubes inside the wall

The Functionality of an Aircraft Wiring Harness

Similar to how a car’s harness directs electrical impulses, a plane’s wiring harness does the same for the complete aircraft.

The engine, landing gear, wings, and fuselage are only some of the functions it regulates.

Wire harnesses typically have a great deal going on inside of them.

Miles of cables, wires, and thousands of individual parts make up an airplane wiring harness.

In addition, they all have to function together to keep the plane flying smoothly.

Today’s aircraft manufacturers must also keep up with rapidly developing technologies and upgraded aircraft wiring connections to support cutting-edge additions.

In addition to improving efficiency in production and manufacturing, an aircraft wire harness also makes it easier for mechanics to identify and repair planes experiencing technical difficulties.

Wire harnesses eliminate the need to install the electronic systems of a humongous plane separately.

When problems arise and maintenance is required, mechanics must identify the affected component to fix it.

Three Categories of Parts in an Aircraft Wiring Harness

The aircraft you will put it in is a significant factor in determining the specific elements and components of the wiring harness when designing a plane that meets military specifications; there are many things that you have to take into account.

These are the three types of airplane components.

Standard Components

In a plane’s electrical system, the military will often have the final say over the components known as MIL-SPEC (military standard).

The letters M or MS appended to the beginning of the serial number designate them as a military issue.

Some are prefixed with the letters NAS to show that they conform to the National Aerospace Standard.

A few standard component prefixes exist, but these two are the most prevalent in a military plane’s wiring harness.

On the other hand, the military and many other aerospace sectors.

Nonetheless, the government must certify specific manufacturers before you can consider them as authorized suppliers.

Non-Standard Components

Non-standard components are frequently variants of commercially available components that meet a slightly different military standard.

Original equipment manufacturers can dictate the criteria for non-standard components (OEM).

Original Equipment Manufacturers also have the option to permit which of their suppliers to produce non-standard components.

However, the cost of a non-standard element for an airplane harness tends to be higher since so few exist.

Commercial, Off-the-Shelf Components (COTS)

Manufacturers mass-produce COTS components in response to market research and consumer demand.

The producer can improve the design of the components without permission from the government or the defense.

A manufacturer can create their parts and assign them unique part numbers.

As with the other two components, you can purchase COTS options from vendors at a reduced cost.

However, manufacturers have exclusive power over the distribution of COTS components, allowing them to set prices and determine market share.

Furthermore, they have the freedom to alter or amend any requirements.

However, it might cause a problem as it becomes essential to source new components for a plane’s wiring harness due to a depleted supply.

Aircraft Wiring and Connection

Aircraft wire harnesses have wiring that is miles long.

Therefore, you need to plan and structure them precisely to prevent problems during and after construction.

Thus, the first step in any design process is the creation of a schematic in CAD software. It serves as a guide for subsequent construction.

Insulating materials used to be a one-size-fits-all affair, but nowadays, many options are available to meet various needs.

The signal you send, and the system’s electricity dictate which wires are used. Wire insulation also shifts with these variables.

It would also help to label the wires so that assembly and repairs don’t mix them up.

However, when picking a connector, you should remember these three things.

The number of connections that the connector can accept should come first.

The second factor is the thickness of each wire, and the last is the type of wire to enter the aircraft connector.

Conclusion

The aircraft wire harness is based on different wires and connectors.

Moreover, other standards, non-standard, and COTS parts make the harness complete and functioning.

While choosing the elements, you need to look into your requirements.

Then you will get to design the schematic using CAD software.

At Cloom, we offer wiring harnesses and cable assemblies to make your connection safe and reliable.

In industrial plants, electrical power issues are pretty common. Current harmonics, voltage unbalance, and current unbalance some of them. 

These issues lead to abnormal functioning of the electric power systems.

Of all of them, the unbalanced voltage condition is the most hazardous.

Let’s learn about voltage imbalance issues and how to prevent them.

What Is Voltage Imbalance?

There is no particular definition of voltage imbalance, it is simply the voltage difference between different phases. 

Generally, in three-phase motors or polyphase systems, the voltage between different phases should be equal or nearly equal.

However, due to some issues, three-phase voltages become unequal, resulting in negative or zero sequence currents.

Major Effects of Voltage Imbalance

Sometimes, there are extensive voltage imbalances.

As a result, it impacts polyphase motors and other electrical loads. 

Unbalanced voltage mainly causes motor failure due to extreme heat.

Because the voltage unbalances produce high unbalance currents, these currents produce heat and increase the winding temperature.

As a result, it can damage motor insulation. 

Also, a severe imbalance in voltage can lead to the overheating of components in the motor, and there can be severe or permanent damage to the motor.

Motor failures, in turn, lead to user facility downtime.

Voltage imbalance also creates negative sequence voltage, and this negative voltage produces opposite torque.

As a result, there is vibration and noise in the motor. 

Sometimes, imbalances in power systems also lead to transformer failure, and relay malfunction is also one of its adverse effects.

Image: motor winding

Causes and Sources

Several factors affect voltage imbalance in a distribution line, which is either general or motor-related.

General:

• Unequal distribution of single-phase loads
• Overloading in feeders due to electrical faults
• Faulty equipment
• Unbalanced power source voltage

Motor:

• Wrong tapping in the transformer
• Unbalanced load in three phases
• An Unequal impedance of the three-phase distribution system
• Unbalanced loading of capacitors

Image: overload

Voltage unbalance standards

Specific standards decide the limit of voltage unbalance, and ANSI recommends a 3 percent unbalance in voltage for electrical systems.

You must take this percentage under no-load conditions.

However, according to Pacific Gas and Electric, this voltage imbalance percentage should not exceed 2.5.

According to NEMA MG-1-1998, there is just a 1 percent unbalance limit, and this rule is the strictest.

NEMA is an association that represents motor manufacturers.

Per the NEMA rule of 1% voltage imbalance, a current unbalance 6-10%.

On the other hand, some makers fix the current imbalance value to less than 5%.

It is essential to get a valid warranty, which means the makers’ requirements are stricter than NEMA MG-1.

At times, disputes arise between customers and makers due to this difference.

Thus, you need to check the service guidelines of the utility at a specific location.

Testing for Voltage Unbalance

To test the voltage unbalance, you must measure phase-to-phase voltage.

The 3-phase system has a connection across phases.

Thus, do not measure phase-to-neutral voltages.

Take the phase-to-phase voltage readings with a voltmeter. 

According to IEEE, it is a ratio of the positive and negative sequence components.

Now, use this formula to calculate the percentage of voltage unbalance.

Voltage unbalance percent = 100* (maximum voltage deviation/average voltage)

The average voltage is the average of voltages across all three phases. 

This formula identifies the unbalanced voltage magnitude present in the system.

If there is any, you must determine the problem source.

The unbalanced situation can be due to the motor or the power.

Follow these steps to know the source of unbalance:

• Firstly, measure and note down the current through each load
• Secondly, rotate all power lines (three) by one position. However, please do not change the order; it will change the motor’s rotation.
• Now, again measure the current across all leads in this new position.
• Now, again rotate all power lines by one more position.
• Again, record the current across all lines in the new position
• For every three rotations, calculate the average value of the current. Observe the power line/motor lead combination that shows the maximum deviation from the average current.
• Finally, compare all three power lines with the most current deviations. If the combination always has the same motor lead, the problem is with the motor. On the other hand, the same power line in combination indicates a problem with the power supply.

Image: electrician testing industrial machine

Voltage Unbalance Mitigation

The issues of power quality are obvious in distribution networks.

You cannot make voltage imbalance as Zero in a distribution system because of three reasons:

• Firstly, the connection and termination of single-phase loads are random
• Secondly, due to the uneven distribution of loads in the three-phase system
• Finally, due to the asymmetry of the power system

However, you can mitigate it after a thorough voltage imbalance study.

To reduce the effects of voltage unbalance, you can use the following:

Utility level methods.

• Redistribute single-phase loads across all phases.
• Reduce unequal impedance due to transformers and lines
• Decrease single-phase regulators to correct the imbalance. However, you must use them carefully.
• Use active and passive electronic systems to correct voltage imbalances.

Plant-level methods:

• Do load balance?

• Avoid connecting sensitive equipment to systems with single-phase loads
• Make sure that you size the AC side and DC link reactors properly.
• It reduces the effect of voltage imbalance in speed drives.
• Have passive networks.

Conclusion

The impacts of Voltage imbalance are harmful to motors.

Thus, you must adequately find and correct the problem.

When you balance voltage, the life cycle of equipment becomes better.

As a result, you save time, energy, and maintenance costs.

Thus, it would be best if you properly tested the electrical equipment.

We can help you in managing your electrical systems.

We deal in premium quality cable assemblies.

There are two things you want in your facility.

First, you need the gear to deliver optimal and consistent performance. Additionally, the equipment shouldn’t cause any damage or accidents, with injuries. 

Live testing can help to maintain both goals. It involves checking if the gear works right while it’s operating. 

But, there is something you should know before working near or around the energized equipment.

What Does Live Testing Mean?

Caption: An electrician working on maintaining electrical equipment

If you handle electric testing sessions, you should turn off the power supply to the gear.

The experts recommend deactivating it for personnel safety.

The problem is that you can’t test a device’s performance without checking how it works.

Live testing involves checking the system while the power supply is active.

It helps in finding faults, but it also carries more significant risks.

Therefore, you should ensure trained electricians handle the action.

The experts suggest that live testing is possible on all gear and conductors that work at no less than 50 volts.

The Electricity at Work Regulations suggests when live testing should occur:

• If the device vitals need to remain “live” at all times.
• The electrician can do the checks while the device is “live.”
• If you take all precautions to maintain safety and prevent injuries.

Tests That We Carry Out “live”

The device list is up to you to decide.

As for the series of tests to take, here are the ones that the experts recommend.

Polarity Tests

This test involves circuit breakers, switches, and fuses.

In other words, these are single-pole devices connected to the PHASE conductor.

The idea is to confirm the relationships are optimal.

That way, we ensure the electricians did the setup right. It minimizes the damage risk for the entire apparatus.

And you’ll only need a plug-in tester. You’ll read the numbers on the charts to confirm the correct polarity.

Earth Loop Impedance Test

Let’s assume that a fault occurred in the electrical system.

The circuit breaker or fuse should get enough current flow to protect the faulty circuit.

It ensures the earth cable resistance is low enough to continue operating correctly.

You do loop tests to see if the circuit disconnects on time to keep a fire or overheating from happening.

You can use no-trip testing with three wires.

Label testing involves connecting these to earth, neutral, and live conductors.

Make sure the test current isn’t higher than 15mA.

The process won’t trip MCBs; you don’t have to go around RCBOs and RCD.

That ensures you save time with this test.

Prospective Short Circuit Test

Caption: Technician testing a control panel

If this fault happens, the cable should handle enough current to blow a fuse or trip the MCB.

The guidelines indicate this should happen within five seconds for fixed gear. However, the time reduces to 0.4 seconds for any portable equipment.

The prospective short circuit test ensures the cable handles the fault as expected.

During this test, you check the current in live conductors when a fault occurs.

It’s necessary to check Line to Neutral and Line to Line in three-phase setups.

For single-phase installations, check Line and Neutral. Furthermore, write down the result in hundreds of amps.

Residual Current Device Test

If an electrical fault occurs, there should be a safe RCD “tripping.”

You will trip it on purpose during this test.

That way, you confirm it works quickly if a fault happens.

The RCD will turn off all the channels where the circuit receives power if it doesn’t trip.

The residual current device test is vital to keep electrocution incidents.

Here is how to do it:

1. First, connect the equipment and adjust the desired RCD rating. The test starts with half of the rated tripping current of the device.
2. If the RCD doesn’t trip, increase the rated tripping current. The average time to trip out is 0.3s.
3. Increase the test rating to 5x the rated current. You should note that the RCD takes less time to trip than in the previous step. The change will only be minimal.

Electrical Lnjury Risks When Fault Finding and Testing on Energized Equipment

The problem with live testing is that it includes significant health hazards.

After the device selection, minimize the risks of potential issues.

Here are the problems that might happen!

Electrical Shock

Caption: An illustration of an electrical shock

If the electricity goes through your body, you have an electric shock.

The consequences might be dangerous and even fatal.

Electric shocks can cause severe burns on the surface and inside your body.

They can lead to a fall because they make you lose your balance.

It’s also possible a shock starts to come into contact with a conductor with a higher voltage.

You might also have problems making any movements, or your movements might be involuntary.

Electrocution

This term also refers to an electric shock.

However, electrocution describes a severe injury or fatal consequences of the shock.

The health risk depends on various factors and not only the voltage.

You must also assess how much current goes through the body and for how long.

Your breathing can stop if a current of as little as 30mA (1 amp) goes through your organism.

Winds over 1A can cause permanent damage to cells and burns.

A standard 125V circuit in households can send 15 amps of current to your body.

Therefore, it’s hazardous, and caution is necessary when dealing with electricity. 

Arc Flash

Caption: A spark explosion

A significant electrical explosion happens when an arc fault happens.

The first byproduct of that event is an arc flash.

That includes heat and light that come from the blast.

Caption: how arc flash looks

If we are talking about the temperature, it can go up to 19,000C, and the usual range is about 3,000C.

As a comparison, the Sun has a temperature of 5,000C on its surface.

The heat from the arc flash can burn your clothing, skin, and even internal organ damage.

Therefore, it could have serious consequences.

Arc Blast

Apart from the flash, the explosion will create an arc blast, a pressure wave around the device that explodes.

The shots are strong and can throw you on the other side of the room.

Furthermore, they are loud, so you could deal with hearing damage.

Even your brain functions are in danger.

It’s not only the people who the blast can throw around.

The product can throw machinery and tools around, hurting you.

Burn Injuries

The dangers above can involve burn injuries.

So, they are a significant health hazard to the electricians and people in the facility.

The burn degree can vary depending on how close you are to the arc flash.

Some burns might be superficial, but others can be dangerous and even fatal.

What Can You Do to Minimize Health and Safety Risks?

The actual regulations depend on your location.

However, here is what you should consider when testing public devices.

Assess the Risks First

Caption: Risk assessment illustration

What can go wrong during the live or “near-live” testing?

You should hire a qualified person to assess the risks.

Apart from the arc flash and direct electric shock, you should consider conductive materials, and these have paths that the prospective fault current can follow to cause a shock.

Here is how risk assessment works:

1. A qualified staff member should assess the current situation. That involves finding potential electrical and other risks during the test. Make sure it’s comprehensive coverage of potential hazards.
2. The testing should comply with any laws and regulations.
3. There should be a risk assessment report in writing.
4. The report should contain suggestions on how to manage the risks.

Don’t Forget the SWMS

This is short for a Safe Work Method Statement, and the regulations require it.

You need a qualified person to write it; this report can include the actual risk assessment.

Here is how writing SWMS works:

1. Talk with any relevant workers to find potential risks.
2. Discuss which work is a part of the plan for the test.
3. What measures can help to manage the risks? It should include additional info on each risk control action. Additionally, it should review if the relevant staff takes that action.

The person doing the test should be aware of the SWMS.

If you change any work or safety procedures, you might need to change this document, too.

Use Personnel with Adequate Training

It’s needless to say that a professional should do real-time testing.

They should understand how devices work and know how to use relevant instruments.

Furthermore, they should also be aware of safety issues.

Knowing how to act to minimize risks is vital for safety, and it ensures that the ongoing testing efforts and the process go smoothly.

The Importance of the Protective Gear

Industry experts call this personal protective equipment (PPE).

It’s vital to adjust it to the needs of the individual tests.

Here is what protective equipment staff should use:

• Face. The individual should wear a full shield in case of an arc flash. Check the availability status of the shield before beginning the test. Additionally, don’t wear spectacles with metal frames.
• Gloves. What voltage do you expect? The authentication options should only include gloves that can handle the expected voltage.
• Clothing. The highest thermal rating with flame-resistant materials is the smart move. You don’t want to wear synthetic or flammable material.
• Footwear. Your shoes might be conductors. Make sure they aren’t before you enter the pre-production test environment.

Safety Barriers, Signs, and Observers

Caption: A warning sign

A safety barrier helps avoid contact with a dangerous part of the electrical setup.

You’ll need to assess whether these barriers are necessary for individual tests.

There shouldn’t be issues with an unauthorized request because safety is everyone’s top priority.

You can use plastic, wood, or another non-conductive material for the barrier.

Make sure the border won’t fall if you accidentally hit it.

It’s the minimum version of sturdiness it should have. 

It would help if you had safety signs, too.

These are warnings to people who might enter the test area, and you can avoid a civilian disrupting the ongoing testing efforts and potentially suffering injuries.

The regulations also recommend a safety observer.

For each piece in the device list, they monitor optimal risk management on the spot.

If an emergency occurs, the observer should act to minimize the risk.

Knowing the facility and device details can help with that. 

The observer should talk to the staff member doing the test.

And forget about mobile devices because communications need to be direct and effective.

Work Completion

If you deactivate the power supply, don’t rush with energizing the devices.

Here is what you need to confirm first:

1. Check if you removed any waste or private devices you used during the individual tests.
2. Place covers and guards back in their places.
3. Make sure to remove and note any temporary earthing equipment or electrical bonding.
4. You must warn employees that you have finished unit tests and plan to turn the power on.

What If You Don’t Finish the Work?

A single day might not be enough for the entire assembly of tests.

If that happens, you can leave the unit tests for another time. However, make sure that the place remains safe.

The safety actions when postponing application testing include:

• Shroud or terminate exposed conductors.
• Furthermore, it would be best if you physically secured them.
• Make sure to place warning signs about the tests on any device windows you plan to check
• Put additional information panels for other employees to avoid potentially risky areas.
• Make sure you inform the workers about the current index status. That way, you ensure they can continue to work safely.

Use Approved Equipment

Here is another crucial safety point.

If you want to test an actual device, use only approved equipment to ensure accurate testing results and show precise device vitals.

If you don’t have adequate equipment, don’t use an alternate version, which increases the risk of something going wrong.

Make a careful device selection and use only proven instruments during testing.

Caption: Electrical equipment

Conclusion

There are situations when only live tests can give more info on the device’s vitals.

If you plan to test equipment while the power supply is active, consider safety a top priority.

You can protect everyone involved in the approved ongoing testing efforts.

And if you need help with electrical wiring, don’t hesitate to contact Cloom.

We have years of experience and can meet any requests your facility needs!

What happens when the primary power source goes off?

An alternate source starts operating and powers the electrical equipment. 

How does this happen?

A transfer switch switches the electrical loads between two power sources. 

Sometimes, these transfer switches are manual.

An operator throws the switch whenever the two power sources lose or gain power.

However, now you can find an automatic transfer switch.

This switch has a specific control panel system that makes the switch automatic.

The control panel detects the primary source failure and leads to the start of the engine generator.

To ensure that the ATS works properly, you must conduct ATS testing.

Here are the helpful automatic transfer switch testing procedures.

How do Automatic Transfer Switches Work?

The automatic transfer switch is a self-acting device.

The control logic of the switch is automatic and microprocessor-based.

It regularly monitors the frequency and voltage of power sources.

In general, automatic transfer switches connect to the primary power source or utility by default.

However, when the primary power source fails, it connects to the alternate power source, i.e., a generator or backup utility. 

The switch transfers the load to the primary power supply on normal power restoration. 

You have to install these switches at the location of the backup generator.

NFPA guidelines for automatic transfer switch testing:

• You must do inspection and operational testing.
• Test all the EPSSs and internal and mechanical components once a month.
• Operate the automatic transfer switch monthly.
• You must perform an electrical function test periodically, including transferring the switch to the alternate power source from the standard source and returning it.

Image: ATS installed under a building water

Automatic Transfer Switch Testing Procedures– Monthly Automatic Transfer Switch Functional Testing

Most facilities, such as hospitals, data centers, factories, etc., require continuous power to deal with power failure circumstances.

They use an emergency system for alternate power sources.

This can be an engine generator or any other backup utility. 

If your automatic transfer switches (ATS) do not work, it may lead to serious issues.

Thus, you must do operational testing of automatic transfer once a month to ensure the smooth working of the switches. 

Precautions to take:

• Firstly, make sure that you close the enclosure door of the generator set to prevent injury.
• Secondly, ensure that the normal and emergency power sources should be there.
• Finally, ensure that the emergency power sources should be in working condition.

Follow these steps for electrical operation transfer testing of an ATS and standby generator

• First of all, turn the isolation handle anti-clockwise to the test position. This will turn on the transfer switch connected to normal and normal source-accepted lights.
• Now, turn and hold the transfer control switch clockwise to the transfer test. The delay to the engine start timer begins its cycle. This cycle will take 15 seconds until the engine starts and runs. When the cycle completes itself, the “engine start contacts” close, and it starts the generator. With this, the emergency power source lights will turn on.
• This triggers a 2B time delay, and after this, the transfer switch will work in an emergency position. As a result, the transfer switch connected to the emergency light or the S2 position LED turns on. Along with this, the transfer switch connected to normal will turn off.
• After the feature 3A time delay, the transfer switch will return to the normal position.
• To retransfer immediately, turn the transfer control switch in an anti-clockwise direction to retransfer delay bypass. As a result, the transfer switch connected to normal will turn on, and the transfer switch connected to emergency or the S2 position LED will go off. Now, turn the isolation handle clockwise to the connected position.
• After the feature 2E time delay, the generator will stop. The cycle of the delay engine stop timer starts. During this time, the generator set runs without load.
• It is important to give a minimum 5-minute delay for the unloaded running of the generator. Let the engine cool down during this time. 

With these steps, you can verify whether:

• All the functions are running correctly when the load shifts to an emergency power source in case of primary source failure.
• S1 (source1) LED and S2 position LED are working properly.
• There is any vibration or noise during operation.
• All the time delays during the load transfer are working correctly. 

Automatic Transfer Switch Testing Procedures– Annual preventive transfer switch maintenance process

To ensure the reliability and life of the automatic transfer switches, proper maintenance is important. 

The switch uses dangerous voltage that can shock, burn, and even death.

Thus, make sure that you disconnect ATS with the normal power source and the emergency power supply system before any automatic transfer switch maintenance activity.

• First, conduct a visual inspection and look for any dirt, dust, or moisture. Remove all the dust with the help of a soft brush or a vacuum cleaner. Clean the moisture with a cloth.
• You will find a manual operator handle on the switch for maintenance purposes. You must check for any issues in manual operation. 
• Next, remove the transfer switch barriers. Check all the internal components and contacts of the switches. Contacts must last till the life of the switch. Reinstall all the barriers carefully.
• Due to harsh operating conditions, the lubrication on the switch may get lost. Thus, apply lubricants on all movements and linkages.
• Then, check the connections of all cables and wires. Re-tighten them if required.
• Finally, ensure the switch has manual transfer warnings to avoid accidents.

Automatic Transfer Switch Testing Procedures–Who performs this test?

If it is a normal automatic transfer switch testing, any local person can do it.

However, for advanced testing procedures, you have to contract out this task to experts.

When doing so, ensure the contracting company meets all the safety requirements of the OSHA (Occupational Safety and Health Administration).

Also, the company must have industry-trained technicians to do this job.

Having qualified personnel means they are very well familiar with the procedures, related risks, and safety procedures of the ATS.

Conclusion:

Testing an automatic transfer switch ensures that you get a continuous power supply.

It will also ensure that the load transfer process, from primary power supply to emergency power supply, is efficient, safe, and fast.

During the installation of ATS, if you need any help regarding wires and cable assemblies, contact Cloom.

We deal in high-quality ones for your electrical system needs.

Have you seen a sudden blast or shock wave in a power system?

Well, most of the blasts occur due to an electrical fault.

Short circuit analysis is harmful to every power system.

It can damage electrical equipment. It can also injure or harm the working personnel.

Short circuit analysis is an important part of electrical maintenance.

So, you had better do it when you add new cables, circuit breakers, etc., to the power system.

However, before that, you must know what a short circuit is.

What is a Short Circuit?

When high currents exceed the limit of protective devices, it becomes dangerous.

It occurs when two points of different voltages connect.

And the electric current travels to an unintended path of low resistance.

Owing to the low resistance, there is a high flow of current.

Contact between two points of different voltages creates the wrong path.

So, energy is rapidly released in the form of heat and magnetic fields.

This creates a shock wave, overheating, explosions, fires, or circuit damage.

Most of the time, short circuits occur due to faults.

However, at times, you can do it for testing purposes.

Image: short circuit and burnt cable

In an Alternating current system, a short circuit can occur:

• If one phase touches another phase
• T phase touches the ground
• If the phase touches neutral
• If the windings of a machine touch each other in one phase

Direct current system results in a short circuit in the following circumstances:

• When two poles touch the ground
• When there is contact between poles.

Different Faults that Occur Due to Short Circuits

Short Circuits can lead to faults within the system. They are:

Bolted fault: Sometimes, you bolt two conductors of different voltages together or to a power source.

This source of power is bolted to the ground.

This results in a bolted fault.

No fault resistance exists, so the highest possible current passes through the system.

Bolted faults are quite unusual and occur by chance only.

You can use bolted faults to speed up the operation of protective devices.

Arc fault: This fault occurs when current flows through two conductors which are not in contact.

When there is high system voltage, an arc forms between system conductors and the ground, this arc has very high resistance.

A simple overcurrent protection device cannot detect this arc. It can cause severe damage to the cables before becoming a complete short circuit.

Also, it may lead to arc blast or arc flash, leading to severe injuries.

Image: electric cord exploding

Ground fault: A wrong connection between the conductors and the earth results in this fault condition.

The current flows through a low-resistance path to the ground.

This results in dangerous circulating currents that damage the equipment at high voltage.

This path may lead to serious injuries when it passes through the human body.

Most of the power systems are designed to bear one ground fault.

However, a second fault leads to electrical components failure.

The electrical shock from the ground fault also stops the human heart from functioning.

Symmetrical faults and non-symmetrical faults:

Polyphase systems can have either symmetrical or non-symmetrical faults.

The differences between them are:

• Symmetrical fault current affects all phases equally. On the other hand, non-symmetrical will affect only a few or all phases unequally.
• You can analyze symmetrical faults. However, the non-symmetrical fault current is difficult to detect.
• Non-symmetrical faults are common, while symmetrical faults account for only 5%.

Why do Short Circuits Damage Equipment?

Sudden short circuit results in extensive equipment damage.

Two phenomena increase the risk of equipment damage during a short circuit event.

Image: overloaded circuit board

Thermal phenomenon: Short can lead to energy releases through intense heat.

This is the thermal phenomenon. This heat damages an electrical circuit in various ways:

• The melts the ends of the conductors.
• Causes damage to the insulation.
• It generates electric arcs.
• It destroys the thermal elements in the bimetal relay

Electro-dynamic phenomenon: Sometimes, the short circuit current creates high mechanical stress.

This results in physical damage to the conductor’s windings and conductors.

Also, it can result in the repulsion of contacts within conductors.

Protective Devices for Short Circuits

An overcurrent situation is dangerous for equipment and humans.

In such situations, you need to use a protective device.

The protective device detects any fault current. On detection, it trips the circuit at once.

This prevents the current from reaching its maximum limit.

These electrical protection devices have two features:

• Breaking capacity: When a high current travels, the protective device will break the circuit. The highest value of this current is the breaking capacity.
• Closing capacity: The maximum short circuit current at which the device will reach its rated voltage.

An electrical circuit has different power system protective devices. However, the most common type is:

Fuse: This protective device gives you high breaking capacity.

Circuit breakage occurs even at low voltage. However, you have to replace it once it trips.

The fuse protects the electrical circuit from electro-dynamic stress.

This protective device is suitable for phase-by-phase protection.

Image: electrical fuses

Circuit breakers: Circuit breakers break the circuit automatically in a short cut-off time.

Circuit breakers separate the load from the power supply.

This will protect the electric circuit from damage.

Unlike a fuse, it protects the electric circuit against thermal and electro-dynamic effects.

Image: electricity distribution box with circuit breakers and wires

Ground Fault Interrupter: The current flows in the charged conductor in an electric circuit and returns through the neutral conductor.

Ground Fault Interrupter (GFI) detects any difference in this circuit current.

If there is a difference in circuit current, current flows stop at once.

This protective device can protect you from the shock wave.

You can use ground fault interrupters in your homes for bathrooms and kitchens.

This comes inbuilt in an electrical socket. You do not get over-current protection through a GFI.

As a result, any circuit that uses a GFI also uses fuses or circuit breakers.

Along with these protective devices, there are several other protective devices.

You can use them to 

• Find any changes in the voltage level and current
• Observe the ratio of voltage and current
• Offer protection against over-voltage and under-voltage
• Detect phase reversal and reverse current flow

What is a Short Circuit Analysis?

You can do this analysis for short circuit fault current calculations.

During an electrical fault, a certain current flows through the electrical system.

You can calculate the maximum fault current with this circuit study. However, don’t miss the contribution from generators and synchronous motors when calculating maximum fault current.

Also, take note of induction motor contributions. 

Compare these values with the equipment ratings of short circuit protection devices and installed electrical equipment.

Ensure that electrical equipment can bear the short circuit energy at each point.

Create fault currents at different locations for complete information.

Now, repeat the study. With this, design a suitable relaying system to protect the devices.

Your equipment will fail to handle a fault current in low-rating power systems.

This leads to major destruction in the power distribution system. 

For circuit study, you need power system analysis software that complies with IEEE standards.

For large systems, do circuit calculations for switchgear and relay settings. 

Short circuit analysis is important to meet several standards. 

According to NEC110, you must do short-circuit study for all electrical equipment and power systems.

This is important for NEC and NFPA labels.

For this, you need to meet the guidelines of two common standards; One is ANSI, and the other is IEC.

With ANSI standard guidelines, you can select power circuit breakers.

However, you do not get any information related to NEC110 labeling. On the other hand, the IEC 60909-3:2009 standard is more general.

Its guidelines help in performing a study of an asymmetrical circuit in a 3-phase electrical system.

You can use either of the calculation methods. You will get almost similar results.

Benefits of Short Circuit Analysis

Conducting a short circuit analysis is beneficial for your installation. 

• Firstly, it avoids unplanned outages and any disturbances in essential services.
• Secondly, it reduces the risk of fires and equipment damage.
• Thirdly, it ensures the safety of people.
• Finally, it ensures the safety and protection of the power system. This makes the system more reliable.

Software for Short Circuit Study

Some of the software programs for this are:

• ETAP
• SKM power tools
• Easy Power
• PSS

How to Conduct a Short Circuit Calculation

To apply the coordination of protective relays, a short analysis is essential.

Follow these steps for the circuit study.

Firstly, collect information related to all electrical components.

Secondly, draw a linear network of the system. The diagram must show the connections of all electrical components. You can also find cable impedance with this power system diagram.

Thirdly, select the suitable short circuit study software. Put system data as input. Do short-circuit calculations at different points. Put these results as output.

Now, organize the results. Compare the short circuit current calculations with the short circuit rating. The circuit values you compare must be from the same point. If the short circuit current is higher, mark that as dangerous.

Finally, prepare a detailed report of the study.

At last, suggest any corrections that need to be made.

Conclusion:

Don’t hesitate to do a circuit study if you doubt a short in an electric circuit.

Short circuits result in damage to wires and cables.

So, if you want high-quality cables and wires, Cloom is here to help you.

We help you with top-rated wiring harnesses and cable assemblies.

Contact us for more details.