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How Are Bus Plugs and Ducts Used in Manufacturing?

All buildings whether commercial or residential require some sort of electrical power in order to provide lighting, outlets and other electrical devices. For commercial buildings, you have power needs for machinery, lighting, cooling systems, and other types of electrical needs. Typically, in a residential building, you have electrical service entering the house with cables. This is different then how electrical power is distributed in commercial and manufacturing settings.

Commercial buildings, especially those used by medium or large-scale manufacturing businesses use a larger type power distribution system that requires a much different way to run power through the manufacturing spaces of the building. Unlike residential power distribution which uses cables to carry the power throughout the home, commercial building use bus ducts or sheet metal runs with either aluminum or copper busbars.

History of the Busway Power Distribution System

The busway and bus bars were first introduced in the US back in the 1920’s at the request of the auto industry in Detroit, Michigan. The system gave them the necessary versatility that was needed for supplying power to the assembly line equipment that was being used in the manufacturing facilities at the time. Over the years since, there have been numerous innovations that have improved on the original design and installation procedures.


Commercial Power Distribution System Components

Heavy duty machinery typically found in manufacturing plants have unique power requirements which cannot be served by typical power distribution systems that are found in most residential homes and most commercial buildings. For these unique power requirements, there is a power system that is designed especially suited for this type of need. Bus Ducts and Bus Plugs are combined to deliver the necessary power to each machine


Bus Ducts – Bus Ducts also referred to as busways are sections of sheet metal with bars attached to them that are made of either aluminum or copper.  The sections are connected together in order to reach each piece of machinery that is needing the power. This type of power distribution system requires trained, certified professional electricians to install them and ensure that they are in full operation at all times.


Bus Plugs – Bus Plugs are specially designed components that work in tandem with the busbars in a unique type of power distribution system that is typically installed in a large-scale manufacturing facility. Each bus plug is used to connect directly to busways that are running throughout building to deliver the power to equipment like large motor starters and other power switching equipment.

Indoors and Outdoors Power System

One of the benefits of using this type of system in a manufacturing facility is that it can be used both indoors and outdoors to deliver the necessary power to different parts of any operation. The unique design of the system helps to prevent voltage drops across each of the numerous sections of the bus ducting throughout the building.


The system can also be fitted with a trolley system that is designed to deliver power to equipment that is designed to move frequently. There are also cables that are used to deliver the power directly to the trolley itself.


Learn more about J & P Electrical Company and their vast line of new, surplus, and refurbished industrial electrical components including: circuit breakers, bus ducts, bus plugs, disconnects, fuses, panel switches, tap boxes, and transformers at  To contact one of our product reconditioning specialists, call 877.844.5514 today.

Power supply ins and outs

While the switching power supply data sheet may document compliance to over two dozen general specifications, focusing on the input and output specifications and the safety standards that impact installation highlights some of the basics of specifying and integrating the device.

Most power supplies have the input voltage well supported with a nominal range of 85-264 Vac suitable for use with any 115- to 230-Vac supply. The typical voltage frequency range covers any 50- or 60-Hz supplies, as well.

From an integration standpoint, things start getting interesting when discussing nominal current and inrush current. It is common for the input to most power supplies to be internally fused, but adding supplementary fusing or, preferably, a miniature circuit breaker (MCB) to the input that can be turned off and on is best practice. The full load input current is noted in the data sheet and fusing between 150% to 500% of the specification, and wiring with suitable gauge wire, is appropriate. For example, when wiring 2 A to 10 A switching dc power supply, include a 10 slow-blow fuse or MCB and 16 AWG wire to protect input wiring.

From an integration standpoint, things start getting interesting when discussing nominal current and inrush current.

However, be certain that the fuse or MCB can handle the inrush current. While the inrush duration is less than half an ac cycle, it can be six to 20 times the full load input current. This can certainly trip fast-blow current protection devices, so check the manufacturer’s recommendations as slow-blow fuses and circuit breakers are likely needed.

The power supply output voltage and the nominal output current or maximum output power are likely the most important specification for the application, but there is more. From the voltage side, there is output adjustable range, overvoltage protection, voltage tolerance and ripple to consider. These output-voltage specifications can impact sensitive applications, such as analog circuits or test systems, but most 24 Vdc power supplies can deliver the needed potential.

The output current may need a closer look—specifically, nominal output current and current limit method. This includes protection against short circuit and overload. This power-supply output protection often resides internally to the device, but that doesn’t mean additional protection is not needed when integrating it.

Short-circuit protection is often built-in to the power supply and will shut off output power when a short circuit fault occurs. The input power typically will need to be cycle off to on to reset this fault.

Many power supplies use a feed-forward current limit method on the output. This limits the maximum overload current to 110%, 150% or 200% of nominal current, depending on the power supply selected. With this method and when an overload condition occurs, the current continues to rise to the limit, but the voltage drops to maintain constant power. This disrupts the constant voltage feature of a power supply but can help to start an electric motor with high inrush or power through other high-inrush events.

These feed-forward current limit events may cause devices, such as cameras, light curtain controllers or safety relays, to intermittently lose power. The switching power supplies’ built-in protection from overload can also affect the output protection methods required. Adding fuses, MCBs or electronic-circuit-protection (ECP) devices to the output circuit can help to capture and isolate the circuit causing the overcurrent by tripping the protection device.

Translated to design considerations, that means to separate high-inrush dc circuits, such as motors, from low-level circuits, such as controllers, HMIs and safety relays. Distribute the dc power output through multiple protection devices such as fast-blow, non-time-delay or slow-blow circuit breakers depending on the connected load. For even better detection of overcurrent faults, the ECP monitors both current and voltage. A prolonged undervoltage condition can help to indicate the circuit causing the problem.

Designing the dc power distribution to feed power through multiple protection devices also enables the use of smaller gauge wire. The use of smaller wire is common in discrete and analog I/O and other signal cable runs.

The discussion above regarding output short circuit and overload is related to general safety specification, met by many power supplies, for Protection Class 1 (IEC 536 or NFPA 70, Article 725). While Article 725 does cover some low-voltage industrial control, some computer networks and other remote-control, signaling and power-limited circuits, it’s as much about usage and power limitations that differentiate it from power circuits.

Class 1 discusses the portion of wiring in the power-supply circuit between the overcurrent device and the connected equipment. Class 1 circuits have a voltage requirement of less than 30 V and a power restriction of less than 168% of the device’s Volt-Amp rating, and overcurrent protection is required.

Some power supplies meet Class 2 requirements—upgraded output protection for the connected loads. This class focuses on the circuit between the Class 2 power supply and the connected equipment. It protects the circuit from fire and the personnel from electrical shock.

There are many requirements for Class 2 circuits, but wiring to the power-supply load side does not require a fuse if the proper wire is used. An example of this is power over Ethernet (PoE) cables. Without proper current limiting and wire size, 100 cables together in a bundle could cause quite a fire.

Original Source:

Original Author:  Dave Perkon, technical editor

Fused Disconnect Switch vs Circuit Breakers

For all those people who are looking for major differences between fused disconnect switches and circuit breakers, this post will eradicate all your confusions and help you to make the best choice. Before proceeding further, let’s shed some light on why you need devices such as circuit breaker panels and fused disconnect switches.

Electrical circuits in residential and commercial establishments are designed to carry a certain amount of current. Due to any reason, if more current passes through them, it can lead to dire circumstances where sensitive appliances and equipment can be destroyed. In some situations, this overflow of current through electrical circuits can also result in a fire that can prove to be extremely fatal for the inmates of the building.

In order to prevent such a situation from happening, different devises such are used that serve the purpose of protecting overcurrent in wires. These devices, in a current overflow situation, disconnect or open the circuit. This helps in preventing the fire from erupting. Thus, there are fewer chances of any damage to be caused to appliances and equipment installed in the building. Devices such as circuit breaker and fused disconnect switch also work in case of short-circuit situations.

Now that you are aware of the basic function of both these devices; let’s now have a look at major differences between them.

Fused Disconnect Switch

A fused disconnect switch, as the name suggests, is a combination of a fuse and switch. The fuse shuts the circuit off and switch disconnects it in case of an issue. Switches are designed to be shut the power off manually. On the other hand, fuse works in the opposite way. They are made up of a small filament that melt down in case of a current overflow. A fuse’s current rating is preset. Thus, when the current exceeds the rating of the fuse for a longer period of time it melts automatically. As a result, the circuit is disconnected.

A point to note here is that when a fuse disconnects the circuit, it can be used again. Power can only be restored if the fuse is replaced by a new one.

Circuit Breaker

With circuit breaker, there is no issue of getting a new fuse every time it turns the power off due to the overflow of current or short-circuit. Thus, it is often considered a better option for many appliances. Circuit breaker panels can also be turned off in a manual way as they also serve the functions of a switch. This feature makes them handy if you want to do get some electrical work done in the building.

A circuit breaker disconnects the circuit automatically with the help of an electromagnet it features when it detects overflow of current or a short-circuit. After the problems have been fixed, it only needs to be turned back on for restoring power.

A Final Word

To sum it up, both these devices can help a great deal to eliminate issues caused by the overflow of current or short-circuit. As stated above, a circuit breaker disconnects the circuit both automatically and manually and a fused disconnect switch offers the same purpose. The difference lies in their design and functionality. Thus, when selecting them, take into consideration the electrical requirements of your premises for taking the best decision.

Learn more about J & P Electrical Company and their vast line of new, surplus, and refurbished industrial electrical components including: circuit breakers, bus ducts, bus plugs, disconnects, fuses, panel switches, tap boxes, and transformers at  To contact one of our product reconditioning specialists, call 877.844.5514 today.


How Are Circuit Breaker Panels and Disconnects Used?

Circuit Breaker Panel

A circuit breaker panel is the main point from where electricity is passed around to other electrical circuits. Power for your house comes through the service entrance which passes through the electrical meter which records the amount of voltage you use. It then flows through the circuit breaker panel. The panel usually gives out 100 to 200 amps of power. The panel, in short, is just a bunch of switches.

The service entrance wires are attached to terminals called lugs. Lugs are always energised with electricity unless your local power company shuts it off. A dead front cover, which is a metal panel, covers all the lugs and electrical wiring connected to the panel. The dead front cover provides access to every breaker and switch.

The circuit breaker panel always consists of a main breaker which is a large switch. If the main breaker is shut down, then electricity access to every other circuit is cut off as well. However, the lugs remain energised with electricity. Main breaker activity does not affect the lugs. The circuit breaker panel always has two rows for the branch circuits. It includes circuits which provide 15-20 Amps of energy for lighting or fans or other outlets in a kitchen or garage. Branch circuits which are labelled with 40-50 amps of energy are known as ‘double pole breakers’. These supply electricity to high voltage appliances such as dryers or air conditioners. A large breaker may also supply electricity to a sub-panel which is mainly used for electricity in detached r quarters. The panel also has hot & neutral bus bars. Moreover, the ground wires prevent electrocution from happening due to frayed hot wires. Many circuit breakers also consist of disconnectors.


A circuit breaker disconnector is used to isolate the electrical circuit from electricity to maintain or repair it. A disconnector is only used for safety purposes and can be operated either manually or automatically. Circuit breaker disconnectors are off-loading devices which means that they do not contain the workings for controlling electric arcs and should be opened after the current is interrupted by another device.

A circuit breaker disconnect consists of a lock-out tag-out that prevents inattentive operations from happening. These locks are part of a trapped-key interlock system so that there is steady stream of operations.  A switch disconnector combines the properties of a disconnector and load switch.

In disconnecting circuit breakers, the disconnector is integrated so that there is no need to use separate disconnectors. This has the advantage of being reliable and the need for maintenance decreases. The usage of this device is, however, limited as compared to a disconnector because there may be problem which arise while maintenance takes place.

A fused disconnect is used to replace a circuit breaker as it works in the same way and is cheaper. It can turn a circuit on or off and its fuses can provide protection. Having more information about electrical breakers and disconnectors can help you in every-day life. If a small electrical problem was to arise, you’d be able to solve it yourself.

Learn more about J & P Electrical Company and their vast line of new, surplus, and refurbished industrial electrical components including: circuit breakers, bus ducts, bus plugs, disconnects, fuses, panel switches, tap boxes, and transformers at  To contact one of our product reconditioning specialists, call 877.844.5514 today.

MIT engineers build smart power outlet

A team of MIT engineers has developed a “smart power outlet” in the form of a device that can analyze electrical current usage from a single or multiple outlets.

Design can “learn” to identify plugged-in appliances, distinguish dangerous electrical spikes from benign ones.

Have you ever plugged in a vacuum cleaner, only to have it turn off without warning before the job is done? Or perhaps your desk lamp works fine, until you turn on the air conditioner that’s plugged into the same power strip.

These interruptions are likely “nuisance trips,” in which a detector installed behind the wall trips an outlet’s electrical circuit when it senses something that could be an arc-fault — a potentially dangerous spark in the electric line.

The problem with today’s arc-fault detectors, according to a team of MIT engineers, is that they often err on the side of being overly sensitive, shutting off an outlet’s power in response to electrical signals that are actually harmless.

Now the team has developed a solution that they are calling a “smart power outlet,” in the form of a device that can analyze electrical current usage from a single or multiple outlets, and can distinguish between benign arcs — harmless electrical spikes such as those caused by common household appliances — and dangerous arcs, such as sparking that results from faulty wiring and could lead to a fire. The device can also be trained to identify what might be plugged into a particular outlet, such as a fan versus a desktop computer.

The team’s design comprises custom hardware that processes electrical current data in real-time, and software that analyzes the data via a neural network — a set of machine learning algorithms that are inspired by the workings of the human brain.

In this case, the team’s machine-learning algorithm is programmed to determine whether a signal is harmful or not by comparing a captured signal to others that the researchers previously used to train the system. The more data the network is exposed to, the more accurately it can learn characteristic “fingerprints” used to differentiate good from bad, or even to distinguish one appliance from another.

Joshua Siegel, a research scientist in MIT’s Department of Mechanical Engineering, says the smart power outlet is able to connect to other devices wirelessly, as part of the “internet of things” (IoT). He ultimately envisions a pervasive network in which customers can install not only a smart power outlet in their homes, but also an app on their phone, through which they can analyze and share data on their electrical usage. These data, such as what appliances are plugged in where, and when an outlet has actually tripped and why, would be securely and anonymously shared with the team to further refine their machine-learning algorithm, making it easier to identify a machine and to distinguish a dangerous event from a benign one.

“By making IoT capable of learning, you’re able to constantly update the system, so that your vacuum cleaner may trigger the circuit breaker once or twice the first week, but it’ll get smarter over time,” Siegel says. “By the time that you have 1,000 or 10,000 users contributing to the model, very few people will experience these nuisance trips because there’s so much data aggregated from so many different houses.”

Siegel and his colleagues have published their results in the journal Engineering Applications of Artificial Intelligence. His co-authors are Shane Pratt, Yongbin Sun, and Sanjay Sarma, the Fred Fort Flowers and Daniel Fort Flowers Professor of Mechanical Engineering and vice president of open learning at MIT.

Electrical fingerprints

To reduce the risk of fire, modern homes may make use of an arc fault circuit interrupter (AFCI), a device that interrupts faulty circuits when it senses certain potentially dangerous electrical patterns.

“All the AFCI models we took apart had little microprocessors in them, and they were running a regular algorithm that looked for fairly primitive, simple signatures of an arc,” Pratt says.

Pratt and Siegel set out to design a more discerning detector that can discriminate between a multitude of signals to tell a benign electrical pattern from a potentially harmful one.

Their hardware setup consists of a Raspberry Pi Model 3 microcomputer, a low-cost, power-efficient processor which records incoming electrical current data; and an inductive current clamp that fixes around an outlet’s wire without actually touching it, which senses the passing current as a changing magnetic field.

Between the current clamp and the microcomputer, the team connected a USB sound card, commodity hardware similar to what is found in conventional computers, which they used to read the incoming current data. The team found such sound cards are ideally suited to capturing the type of data that is produced by electronic circuits, as they are designed to pick up very small signals at high data rates, similar to what would be given off by an electrical wire.

The sound card also came with other advantages, including a built-in analog-to-digital converter which samples signals at 48 kiloherz, meaning that it takes measurements 48,000 times a second, and an integrated memory buffer, enabling the team’s device to monitor electrical activity continuously, in real-time.

In addition to recording incoming data, much of the microcomputer’s processing power is devoted to running a neural network. For their study, they trained the network to establish “definitions,” or recognize associated electrical patterns, produced by four device configurations: a fan, an iMac computer, a stovetop burner, and an ozone generator — a type of air purifier that produces ozone by electrically charging oxygen in the air, which can produce a reaction similar to a dangerous arc-fault.

The team ran each device numerous times over a range of conditions, gathering data which they fed into the neural network.

“We create fingerprints of current data, and we’re labeling them as good or bad, or what individual device they are,” Siegel says. “There are the good fingerprints, and then the fingerprints of the things that burn your house down. Our job in the near-term is to figure out what’s going to burn down your house and what won’t, and in the long-term, figure out exactly what’s plugged in where.”

“Shifting intelligence”

After training the network, they ran their whole setup — hardware and software — on new data from the same four devices, and found it was able to discern between the four types of devices (for example, a fan versus a computer) with 95.61 percent accuracy. In identifying good from bad signals, the system achieved 99.95 percent accuracy — slightly higher than existing AFCIs. The system was also able to react quickly and trip a circuit in under 250 milliseconds, matching the performance of contemporary, certified arc detectors.

Siegel says their smart power outlet design will only get more intelligent with increasing data. He envisions running a neural network over the internet, where other users can connect to it and report on their electrical usage, providing additional data to the network that helps it to learn new definitions and associate new electrical patterns with new appliances and devices. These new definitions would then get shared wirelessly to users’ outlets, improving their performance,and reducing the risk of nuisance trips without compromising safety.

“The challenge is, if we’re trying to detect a million different devices that get plugged in, you have to incentivize people to share that information with you,” Siegel says. “But there are enough people like us who will see this device and install it in their house and will want to train it.”

Beyond electrical outlets, Siegel sees the team’s results as a proof of concept for “pervasive intelligence,” and a world made up of everyday devices and appliances that are intelligent, self-diagnostic, and responsive to people’s needs.

“This is all shifting intelligence to the edge, as opposed to on a server or a data center or a desktop computer,” Siegel says. “I think the larger goal is to have everything connected, all of the time, for a smarter, more interconnected world. That’s the vision I want to see.”

Original Source:

Original Date: June 15, 2018

Written BY: Jennifer Chu | MIT News Office

Using Bus Plugs and Ducts in Manufacturing

There are millions of different pieces of manufacturing equipment and electrical components on the market today that only make sense to those who use them in their line of work.  Most of which make little to no sense to those of us who don’t use them. For example, what use would you have for bus plugs and bus ducts, what are they and how do they improve manufacturing.

Bus duct and bus plugs are used to distribute power around manufacturing facilities and industrial buildings such as processing plants, metal fabricating plants, and throughout heavy manufacturing areas where the machines aren’t stationary or need to be moved around from time to time.

All manufacturing buildings are powered differently.  For example, power is distributed through hardwiring in the walls of residential buildings so as to connect to all of the electrical outlets in a room. Industrial buildings such as factories, on the other hand, feature larger open floor plans with various machinery dispersed all around the facility, none of which are near any wall or permanent structure. They require a source of power, and in this case, a giant industrial electrical plug, which is where bus plugs and ducts come in.

A bus plug is essentially a component of a busway (industrial extension cord) that is used for delivering power to the appropriate equipment and circuits. Think of a busway as the extension cord you have at home that you use to plug in several connectors, the same applies to the busway and bus plug system, they enable flexibility and can be disconnected and rearranged to allow whatever manufacturing equipment that needs to be powered on virtually any floor of an industrial building. There is no physical hard wiring to the building, a manufacturing business can bring in more equipment without having to wire or rewire the entire electrical system; they simply have to plug in a bus plug into a busway, and voila, they are up and running.

Like with many electrical systems, bus plugs also require circuit protection, which in this case, is through a circuit breaker or a fuse depending on the application. Using bus plugs and ducts is the most economical and efficient way to power large commercial facilities or manufacturing plants and feed all manufacturing equipment, particularly, in areas of the building where the power distribution keeps changing.

Learn more about J & P Electrical Company and their vast line of new, surplus, and refurbished industrial electrical components including: circuit breakers, bus ducts, bus plugs, disconnects, fuses, panel switches, tap boxes, and transformers at  To contact one of our product reconditioning specialists, call 877.844.5514 today.

5 Reasons To Consider Reconditioned Electrical Components For Manufacturing

Just because you think something is broken or doesn’t work anymore doesn’t mean it’s true. There is such a thing as product reconditioning in the electrical industry.  Companies need to be aware that this is a great way to get electrical components for your company especially if working with limited resources. Just because they are reconditioned components doesn’t mean they are of lesser quality than if you were to purchase new components.  In fact, many times the bugs and kinks have all been worked out of the reconditioned components therefore making them more valuable. Here are a few reasons why you shouldn’t think less about reconditioned electrical components and use them for your company.

Lower Costs

Every business is concerned with saving money. Buying refurbished industrial equipment will save your company a great deal of capital. On average, your company will save about 50% to 70% when buying refurbished industrial equipment over new equipment. You’ll be able to use this money in other areas of business to help you grow.

Greater Peace of Mind

Not only do reconditioned electrical components cost less, but you can rest assure that the products you’re getting are completely rebuilt, inspected and tested multiple times to make sure everything works as if it was new. Another benefit as mentioned earlier is that equipment that has been used for awhile and reconditioned has had a chance to have the kinks worked out.  Problems that often arise with new equipment have been worked out and dealt with.

More Stringent Standards

Companies that are in business to reconditioned electrical components know when a product still life has to offer.  Therefore, it is important to purchase components from a reputable company.  This will help to ensure you are getting quality parts that have been processed at the highest of standards.  You will be sure to get the best in reconditioned equipment and components.

Like New Appearance

Reconditioned electrical components are not only rebuilt and cleaned before being inspected, but they are also painted using quality paint and exclusive acrylic enamel chosen for its durability so that they look as good as new.

Increased Inspections

To ensure all refurbished industrial equipment runs right, the product is tested and re-tested again to meet or exceed the manufacturer’s UL certification.  Each component is not only cleaned but also lubricated, reassembled and thoroughly tested before being allowed to be resold.

Learn more about J & P Electrical Company and their vast line of new, surplus, and refurbished industrial electrical components including: circuit breakers, bus ducts, bus plugs, disconnects, fuses, panel switches, tap boxes, and transformers at  To contact one of our product reconditioning specialists, call 877.844.5514 today.



The Electrical Outlet and How It Got That Way

Right now, if you happen to be in North America, chances are pretty good that there’s at least one little face staring at you. Look around and you’ll spy it, probably about 15 inches up from the floor on a nearby wall. It’s the ubiquitous wall outlet, with three holes arranged in a way that can’t help but stimulate the facial recognition firmware of our mammalian brain.

No matter where you go you’ll find those outlets and similar ones, all engineered for specific tasks. But why do they look the way they do? And what’s going on electrically and mechanically behind that familiar plastic face? It’s a topic we’ve touched on before with Jenny List’s take on international mains standards. Now it’s time to take a look inside the common North American wall socket, and how it got that way.

Hubbell’s Plugs

Separable Attachment Plug, US Patent 774,250. Note the round, headphone-like prongs rather than flat blades.
Consider the problems faced by engineers and designers in the early days of the electrical age. They were literally inventing an industry from the ground up, with very little to go on in terms of prior art. Not only did they have to invent the means of producing electricity, they had to come up with absolutely every component that would connect together to create useful circuits for paying customers, preferably without killing them.

One thing customers, particularly residential customers, would need would be a means to temporarily attach electrical devices to the mains supply, without requiring a visit from an electrician to connect them to the fixed wiring of a house or office, which was typically dedicated to sockets for light bulbs. The requirements were simple: provide two contacts, one for the line conductor and one for the neutral, that could remain firmly connected but easily interrupted at need.

Imaginative minds worked on this and similar problems in the late 19th and early 20th centuries, and various solutions were adopted. But it wasn’t until 1903 that Harvey Hubbell, an inventor from Bridgeport, Connecticut, patented his “Separable Attachment Plug,” a device that we’d recognize as a plug and socket. Hubbell’s first pass at a design used round conductors that looked a bit like the plugs used in manual telephone exchanges to make connections, and might have been inspired by them. The detents at the tip of the pins were retained by the spring action of the contacts inside the socket.

A Hubbell plug with flat blades, from the 1905 catalog.








The device worked well, but the manufacturer and businessman in Harvey saw problems. Foremost was the costs behind those round pins, which would have required machining to achieve the tip and detent. Harvey would have known that parts stamped from sheet metal would be cheaper and easier to manufacture, and so he scrapped the round pins in favor of flat metal blades in 1904. Like the round prongs, the flat blades had a detent for retention, and were arranged in a line. Catalogs from the time list dozens of variants of the “Hubbell Attachment Plug,” and the prices shown for each device suggest that Hubbell’s company fared well in the early 20th century.

For reasons unknown, though, Hubbell altered his design in 1912. The two blades were no longer in a line; each blade was twisted 90° to form the familiar parallel arrangement we see to this day. Hubbell continued to sell both styles of plugs and sockets, and by 1915 had sold something like 15 million units, enough to ensure that Hubbell’s design would be adopted as a standard, even without the millions of units also sold by Hubbell’s imitators.


The specifications for the standard wall outlet we know and love today in North America are determined by the National Electrical Manufacturers Association (NEMA). NEMA standards cover a bewildering range of electrical products; we’ve covered their enclosure and weather-resistance standards before. The standard 120-volt, 15-amp outlet is a NEMA 5-15. The third conductor, the ground pin that completes the outlet’s face, is a round or U-shaped prong. It was added to some outlets as early as the 1920s as a safety feature and is now required for all outlets by the National Electrical Code.

The ground connection is interesting. You’ll notice that on three-wire plugs, the ground pin extends further out from the insulated cord body by about 1/8″. The idea here is that the ground circuit will be completed before the line and neutral connections are made when plugging the cord into an outlet, and perhaps more importantly, will be disconnected last when unplugging. That ensures that there’s a path to ground any time a circuit is plugged into the outlet.

Note too that the NEMA standard says the ground pin is actually located above the slots for the line and neutral pins, turning that frowning face upside down. There’s some logic to that — if something conductive should drape across a partially unplugged cord, it’s safer to have the line and neutral blades physically blocked by the ground pin. In practice, though, most outlets in residential and business settings are installed with the ground plug down. But look around the next time you’re in a hospital; chances are, the outlets there are all installed the correct way.

Behind the Face

The internals of a NEMA 5-15 outlet vary by manufacturer, of course, and even within a brand, there are different grades of outlet. The picture below shows two different grades of outlet taken apart. They’re similar in that both the line and the neutral connections are formed brass bus bars, with screw connections on the outside for connection into a building’s wiring, and springy contacts to grip and retain the mating plug. The industrial-grade outlet has thicker bus bars, better contacts, and stouter plastic in the body. You’ll notice too that both grades have the ground pin directly connected to the metal frame of the outlet, which would also be in contact with a metal wall box, if it were mounted in one.


NEMA 5-15 outlet internals. Source:






Considering how much else has changed in the last century, it’s pretty remarkable that Harvey Hubbell’s original plug and socket designs have remained pretty much unchanged. They’ve been tweaked, for sure, and the original idea has been extended to a panoply of configurations for every connection imaginable. There’s no doubt that the design has some deficiencies, but in the end, Harvey’s ideas seem to have won the day by addressing the basic needs.

Original Source:

Original Date: May 14 2018

Original Author: Dan Maloney

7 Things to Know About During Asset Recovery

Asset recovery is the specialized technique that allows companies to go into facilities and complete electrical tear downs and manufacturing plant clean outs.  Companies specializing in asset recovery take resources that are no longer being utilized and resell them after they are put through the reconditioning process. This technique allows materials that would be normally disposed of and allows them to be sold.  Electrical surplus recovery companies do complete manufacturing plant clean outs, taking materials that are going to otherwise be disposed of and turning them into usable assets.  Below, we are going to look at the definitions that one should know during asset recovery and purchasing electrical components that are new, used, recycled, or refurbished.


Harmful materials and disposal costs of material waste can be reduced with recycling.  In the recycling process materials are converted during plant clean outs, generating income as well as preserving resources.


Equipment and electrical components often can be reused in other manufacturing facilities after a plant is closed.  Re-using equipment allows older equipment to be replaced with internal resources before the need arises to make an external purchase.  If the equipment is not currently needed but could be used in the future can be put into storage for later use.  Reusing idle equipment helps companies reduce depreciation, taxes, and capital.


This process begins with electrical components and machinery that has previously been used.  Companies recondition components by taking them completely apart and rebuilding them.  This process is done often during plant clean outs as a way of generating capital.  Components are refurbished and sold to other users at a discounted price.  The process of reconditioning reduces waste and allows companies to offer like new components for resale.


This process involves solvents, chemicals, lube oils and more that have been used to be reclaimed and reused, most often in a manner in which they weren’t initially used.  This allows companies to cut down on waste while being environmentally friendly.


When used or reconditioned surplus inventory is sold.  This occurs when it is no longer viable or useful to the company and there is no reason to store it for reuse later on.

These processes keep companies from literally throwing money away in dumps.  Manufacturing plant clean outs allow materials to be reconditioned or sold as used through electrical surplus recovery shops.  Companies that go in and process industrial plant clean outs greatly help companies recover capital from their previous investments.  It is important to extract every bit of value out of your initial investment.

Learn more about J & P Electrical Company and their vast line of new, surplus, and refurbished industrial electrical components including: circuit breakers, bus ducts, bus plugs, disconnects, fuses, panel switches, tap boxes, and transformers at  To contact one of our product reconditioning specialists, call 877.844.5514 today.

Know what is in your fuse box

Arc faults are one of the leading causes for residential electrical fires.

Each year in the United States, over 40,000 fires are attributed to home electrical wiring. These fires result in over 350 deaths and over 1,400 injuries each year.

Smoke alarms, fire extinguishers and escape ladders are all examples of emergency equipment used in homes to take action when a fire occurs. An Arc Fault Circuit Interrupter (AFCI) is a product that is designed to detect a wide range of arcing electrical faults to help reduce the electrical system from being an ignition source of a fire.

Arcing can create high intensity heat, which may over time ignite surrounding material such as wood framing or insulation.

The temperatures of these arcs can exceed 10,000 degrees Fahrenheit. Arcing may be caused by damaged wires behind a wall or damaged cords that are plugged into an outlet.

This commonly occurs when furniture is pressed up against a plug in an electrical outlet or nails and screws are driven into a wall.

Conventional circuit breakers only respond to overloads and short circuits, so they do not protect against arcing conditions that produce erratic, and often reduced current.

The AFCI continuously monitors the current and is able to selectively distinguish between a harmless arc (incidental to normal operation of switches, plugs and brushed motors), and a potentially dangerous arc —that can occur in a lamp cord which has a broken conductor. This circuit breaker breaks or interrupts the circuit when it detects an electric arc in the circuit.

As of the 2014, NEC, AFCI protection is required on all branch circuits supplying outlets or devices installed in nearly every room of a home.

Older homes that have not been rewired or homes that only have the circuit breaking electrical outlets and not in the distribution board —breaker box—itself should consider consulting an electrician. What’s in your breaker box?

Some homeowners assume that just because they have the electrical outlets with the little red light that can be reset that they have all bases covered, this may be a disguise. Local electrician Brian Jones of Triple J Electric said, “The AFCI at the fuse box and the electric outlet in the home are two different things, it takes a combination to cover all areas that need protecting.” Jones is a state licensed electrician 256-996-8157.

Original Source:

Original Author: Marla Ballard

Original Date: April 4 2018