Frequently Asked Questions

Why do you need a GFCI?

While you may have not heard of a GFCI before, there is a very strong possibility that you use them in your everyday life. GFCI’s are one of the most common electrical safety products in the US, and are also mandated for use in most home, commercial, and industrial environments.

What is a GFCI?

GFCI stands for Ground Fault Circuit Interrupter, and some also refer to them as GFI’s (which stands for Ground Fault Interrupters). GFCI’s work by measuring the balance of electrical current running through a circuit at any given moment. Their main purpose is to protect people from electrical shock occurring because of a short in a circuit. GFCI’s are differentiated by the amount of electrical current they can handle in a given circuit (usually seen as different amperage listings) before they trip the circuit to prevent harm. For example, an at home GFCI outlet takes a lot less electrical leakage to trip as compared to an industrial grade GFCI protecting massive lighting fixtures in a horticulture building.

Where is a GFCI Needed?

GFCI’s are needed in most places, including both homes and in the workplace (in any industry). They are especially needed in any place close to a water source (whether it be a bathroom, kitchen, or outdoors). GFCI protection goes hand in hand with the current NEC (National Electrical Code) guidelines. The Code is updated regularly so to not share old news I won’t go into too much detail regarding exact electrical requirements. As mentioned before, GFCIs are found almost everywhere within a building, but for the sake of differentiation we will look at 3 large encompassing environments you can find them in, and they are as follows:

Residential: Every home requires GFCI protection, and it usually comes in the form of a GFCI outlet retrofitted to prevent a short from coming through the circuit. They are usually installed in two types of ways in homes. The first is through GFCI receptacles, which replace common household outlets to provide more protection. There are also GFCI Circuit Breakers that help people bypass installing GFCI outlets throughout their household (although you still need the outlets anywhere a water source is near, like a bathroom). Since most of the things in your house aren’t pulling mass amounts of power, these GFCI products can protect you on a daily basis without causing problems from unnecessary tripping of the electrical circuit.

Commercial: most offices don’t need much protection beyond receptacles and breakers as again, while there are a lot of electronics being used, they aren’t at a mass amount that would need a higher amount of protection. Other workplaces that have machines that pull a higher amount of electricity need more protection. This can include a commercial kitchen, that would need to have all their larger electrical appliances protected with higher amperage GFCIs (such as dishwashers, stovetops, ovens, etc.).

Industrial: Just like in the commercial settings that require more protection, industrial settings follow the same guidelines. The larger the product is, the more amperage it pulls to work, so you need to find a GFCI product that matches the amperage to provide the protection that is needed to keep these large machines in check.

Why do you need an ELCI?

Unlike a GFCI, you probably don’t run into ELCI’s on a day-to-day basis (unless you live on a boat). While they aren’t as common as a GFCI product, they are still a necessity in a variety of industries to protect workers from electrical shock hazards.

What is an ELCI?

ELCI stands for Equipment Leakage Circuit Interrupter. While it is like a GFCI, it is normally found in just commercial and industrial settings (not households as well like GFCI’s). An ELCI works by monitoring the entire current that leaves a source of electricity through the hot wire and returns through the neutral wire. If there is less electricity returning, the circuit will be tripped by the ELCI to protect the surrounding people (and circuit) from harm. Just like with GFCI’s, the larger the equipment you are using, the higher the amperage capacity your ELCI needs to be.

Where is an ELCI needed?

ELCI’s should be inserted in any circuit where there is a consistent leakage of electricity from an appliance, but it still needs some form of protection. In more detail, that means that this circuit needs to protect humans (and the circuit) up to a specific threshold of electrical leakage so it can’t cause fatal harm (this threshold is usually larger than the Class A designation, 5mA +/- 1). There are a few common applications where there is a constant stream of leakage, such as welding equipment, marina electrical pedestals, and heat tracing applications.

Should You Get an ELCI?

While it isn’t required by NEC standards like a GFCI to protect a circuit, ELCI’s are still essential, lifesaving products that you should see in a lot of hands in commercial and industrial settings.

What is the difference between a GFCI and ELCI?

There are a multitude of electrical safety products in the marketplace, and a lot of them are required by laws and regulations to be installed in homes and at businesses. Two of the most common electrical safety products are GFCI’s and ELCI’s, and we are going to take a closer look at what the products are and how they work differently.


A GFCI, also known as a Ground Fault Circuit Interrupter, is a very common electrical safety product found in every home and business. Sometimes they are also referred to as a GFI, which stands for Ground Fault Interrupter. GFCI’s work by measuring the balance of electrical current running through a circuit at a given time, and if there is an imbalance, they will trip the circuit to stop the AC current (flow of electricity). Their main purpose is to protect people from electrical shock from a short (imbalance or leakage) in a circuit. GFCI’s are differentiated by the amount of electrical current they allow to run before they trip the circuit to prevent harm. This difference can be seen as the required amperage an appliance runs on, so the GFCI protecting a water fountain in a park needs a higher amperage capacity then your toaster at home because it runs at a considerably higher amperage level. GFCI’s are most commonly seen in every home as receptacles (your three-pronged outlets), and in some cases they are actually a part of the circuit breaker. In industrial settings where appliances run on more electricity, they are seen as standalone products that are added on to an appliance to provide required protection. GFCI’s are required in all homes around anywhere there is running water (such as sinks and washer units) and are also required in numerous commercial and industrial areas to adhere to code standards (these areas include commercial kitchens, marinas, health care facilities, and many more).


An ELCI, also known as an Equipment Leakage Circuit Interrupter, is another common electrical safety product, but it is found more in commercial and industrial settings. ELCI’s operate by checking that the entire current that leaves the source of electricity through the hot wire returns through the neutral wire. If there is less electricity returning, then the circuit will be tripped by the ELCI. ELC’s are commonly found in applications where there is a consistent amount of electrical leakage that is deemed safe but needs to be cut off at a certain threshold. Marinas, heat tracing machinery, and welding equipment are just a few of the places in which ELCI’s are found.

Which one do you need?

That depends on a few factors. First off, a lot of codes and regulations are in place that require GFCI’s and ELCI’s to be installed for safety purposes. One place that both are required by NEC code is in marinas. However, there are different places in which these two products are better served. GFCI’s are more adept in a situation where any form of leakage up to the trip level is an abnormality in the appliance. ELCI’s are better with equipment you are using that is leaking more than 6mA constantly. These applications require an ELCI to protect them and the people using them because a GFCI just wouldn’t let that application run under its normal operating conditions.

What does a UL listing mean for you?

Logos have a large presence in branding products, but not all logos come from the brand selling a certain product. One of the most common logos in the industrial and commercial safety industries is UL. Whether you have seen the certified UL logo or not, it pays to know what it means and how UL listed products can benefit you and others in your day to day lives.

Who or what is UL?

UL stands for Underwriter Laboratories, which is a safety science company that has specialized in certifying electrical products for safe use for over 100 years. They aren’t a government entity, so while they aren’t a “requirement” for products to be used in the workplace & at home, they are looked to as the standard for safety in many industries thanks to their positive reputation over the years. One of the major reasons for their reputation is that UL is a third party-provided service that has roots in insurance practices, so their thought process is always how to protect everyone to the fullest regarding any of the products that they have tested to their standards over the years.

Different UL Certifications

UL Recognized: Certification given components of a larger overall product (such as a circuit board powering machinery in a factory). This means that the component itself adheres to the standards, but the entire configured product may not have further UL certifications. This can also pertain to custom made products that need to be configured correctly. For example, if a UL listed product is sent with flying leads (exposed wires), it is sent to the consumer as a UL Recognized product. The product needs to be wired correctly and configured to another UL listed product (Such as a UL certified industrial oven) for it to be registered as the products actual UL listing.

UL Classified: A product has only been evaluated for specific properties to render them workable in select conditions. This means that while it has passed some testing requirements under limited conditions, UL hasn’t officially deemed it safe in every condition.

UL Listed: A product has passed all UL requirements regarding UL’s specific safety standards. Its listing also means that the manufactured product is routinely inspected to ensure that the product is up to the current UL standards. A UL listing is the highest standard mark in their safety measurement guidelines.

UL Certified: An umbrella term that is used by UL that renders all classifications are incorporated (Recognized/Classified/Listed).

Why Buy UL Certified Products?

The UL label is a great barometer in differentiating between the safety of two similar products in the marketplace. It can mean the difference between questioning your safety and being confident that your new product has been proven to keep you protected even in harsh environments. At the end of the day it is your decision on which electrical products you buy, but products certified under UL’s umbrella can help give you more peace of mind regarding your safety and others.

What is the NEC?

Who or what is the NEC you might ask? NEC stands for National Electrical Code. The NEC is the regulation standards for safe electrical wiring in the US that was first published in 1897 and has been routinely updated every 3 years since (the most recent update was in 2023).

Is it Universal?

Yes and no. The NEC is seen as the universal standard for electrical protection, but it isn’t government mandated, so most states and municipalities must adopt these standards for them to be required. Most (if not all) electrical contractors need to know these codes because they provide a guideline for safety of consumers in regard to their application, and again are getting an application/home/job site legally up to code (where it is required). I would post a picture of the states that have adopted the most recent code update, but they are ever changing (more adopting new code updates) and some are in different stages (for example New York is in the stone ages compared to California in line to follow 2023 Code soon after its publishing) so it would be more advantageous for you to google a current map.

What Does it Cover?

That is a very loaded question. If an application has any involvement with electricity and wiring, then there is a very good chance that there is a listed NEC code for it. If you want to find out if there is a specific one, you can either look up NEC code and the product you are wondering about, or if you want a less expansive list you could look up something like, “NEC code for blank”. North Shore Safety has a list of all concurrent electrical requirements involving GFCI and ELCI protection on our website. If you want a closer look, here is the link.Link

Why Do I Need to Know NEC Guidelines?

While you might not think about it, you are at risk of harm from electrical shock on a daily basis at work, on the go, and even at home. The NEC was made to make sure you have as much protection as possible with electronic applications so that you don’t have to worry about potential problems arising from faulty wiring or unprotected electrical systems.

Class A Protection

Whether you are building a new home or a new office building, you have probably heard some mention of needing class A protection on most of (if not all) the electrical products in your new space. But what is Class A protection? Why do you need it? And why is UL (Underwriting Laboratories) and the NEC (National Electrical Code)dictating that it is one of the most important electrical protection standards that you need in your home and in any commercially operating building?

What is Class A Protection?

A Class A GFCI device provides the best protection for personnel and is designed to trip when between 4 mA and 6 mA of current leakage (usually detonated as 5mA +/- 1) to ground is detected. It is also for appliances and wiring configurations rated 150 volts or less to ground & 60 Amps or less, single or 3-phase. This means that, unlike some other GFCI products, there is a lower electrical leakage threshold that will constitute a fault in a circuit, giving you more protection from being shocked from an electrical circuit than from prior protection regulations.

Why do you need it?

NEC standards are adopted by states after they are published over time, with some states lagging compared to others. This means that some states are in tune with the NEC guidelines to provide you with electrical protection in your home and on the go (like Massachusetts, which is the first state to already accept 2023 NEC guidelines in January), while others are lagging behind in making sure their residents are protected from electrical hazards (the city of New York is in the proverbial stone age at the moment, with its most current NEC standard coming from 2008). NEC guideline updates coincide with the updates in electrical appliance technology to make sure yourself and others are provided the most protection when coming into contact with said devices. It is best practice to adhere to the most recent code, even if it hasn’t been adopted by your state at the current time.

Why does UL now require Class A protection?

With using some deductive reasoning, we can assume that UL chose the highest classification of electrical ground fault protection (Class A protection) with the lowest ground fault threshold to make sure that people are in the safest possible environment in their homes and at work. While some products have too high of an electrical operating capacity to use a Class A GFCI (x. Industrial Manufacturing Products, Large Pools & Fountains, etc.), common household appliances and most workplace appliances now require Class A protection under UL classification to deter electrical shock hazards in the most effective way in which their code allows.

Should I have Plug-In or Hardwired Appliances?

Many people ask this question when they are having electrical products installed in their homes and businesses, but what is the right answer in these situations? There are pros and cons to both sides, so let’s take a look.


Appliances that are plugged in carry a wide array of responsibilities. From lamps lighting your home to a desktop that you use at work your plug-in electrical products consume a big part of your day-to-day life. The plus side of plug-in products is that they can be used anywhere there is an outlet to supply electricity. Of course, not all plug-in products use universal outlets (the standard outlet in the US is rated at 15 Amps and 120 Volts). One of the most common outlets outside of the universal standard that people encounter in US homes are known as dryer outlets (NEMA 10-30 for 3 pronged and NEMA 14-50 for 4 pronged outlets). There are also a plethora of other outlets for different electrical needs in different places in the US. Plug-in appliances are also easier to move as they only require a matching outlet to be used.


Appliances that are hardwired have a much shorter list. In homes, one of the most common appliances you will see hardwired is your refrigerator. In workplaces, different industries require different, larger electrical output products. This can range from dishwashers in a restaurant kitchen to welding equipment to even pumping systems in a water park. Hardwiring products gives said product a direct supply of power from a circuit by splicing the appliances wires directly into the circuit, giving it a sustained, uninterrupted line of electricity.

Which Is Better?

From a safety perspective, plugging-in appliances is a lot safer than hardwiring appliances. Taking a practical look at the two options, and especially in a workplace environment, products need to be moved regularly to be cleaned, and that is a major disadvantage for hardwired appliances. When a product is hardwired, the conduit is meant to be permanent and not regularly moved. So, if it is continually maneuvered the conduit can gradually deteriorate, which can also cause the wiring to fray overtime. This can pose a threat as deteriorated wires can cause serious harm to people in any working condition, as electric shocks can cause serious health problems and even death in severe situations. This isn’t to say never to have a hardwired product, as some need too much power for a plug-in outlet to provide, but if having a plug is an option for an electrical appliance, it is far and away the better choice.

Auto or Manual Reset?

Great! You’ve decided that you need a GFCI/ELCI for your given application, but you still have a few more decisions to make about which electrical protection product will be right for your application. One of the main questions we receive at North Shore Safety when a customer is deciding which product fits their needs is whether they need an auto or manual reset unit. It is a great question, and each has their own benefits, so we will look deeper into each decision.

Auto Reset

The question you need to answer when looking for an auto reset GFCI/ELCI is whether you would prefer the unit to restore power to the appliance when you are not there. A great example of this would be a GFCI protecting a refrigerator in a commercial kitchen. For example, if the power goes out during a thunderstorm in your kitchen when you aren’t there; when the power comes back on would you want that GFCI to automatically restore power to the afflicted appliance (the refrigerator)? The answer should be a resounding yes, as it would be a shame for all of your refrigerated items to spoil because the appliance didn’t automatically turn back on when power was restored.

Manual Reset

The same question should be asked again for this decision, do I want my appliance to automatically return to normal operation after a power outage? A great example of an application that should have a manual reset GFCI (one that doesn’t automatically turn back on) is a table saw. If you are working in a factory with a table saw and the power goes out, would you want that table saw to start running again as soon as the power comes back on? This answer should be no, it would be a great safety hazard to have a saw turn back on when you aren’t expecting it. We hope this helped you make a decision on which GFCI/ELCI fits your application best. Also, make sure to remember that these two situations only occur when there is a loss in power, not if a fault occurs in the circuit. If there is a fault in the circuit, you need to contact a licensed electrician to make sure that they can fix the problem so that your application can run uninterrupted in the future.

Specify to Equipment not a Panel

One of the many recurring questions we receive about our products is what electrical requirements they need to specify to for their prospective new GFCI/ELCI. In simpler terms that is how do you decide what amperage GFCI/ELCI fits your needs. Many people think that they need to designate their new GFCI/ELCIs amperage to the amperage listed with their breaker, but that isn’t the case. You should align your new products' amperage with the amperage of the appliance you are trying to protect. A great example of this situation would be a 60 Amp breaker with a 30 Amp drying machine as a part of the circuit. You could get an NSS LineGard 60 Amp Class A GFCI to protect that 30 Amp drying machine (as it still has the designated Class A 5mA +/- 1 trip threshold), but you could potentially save over $1,000 (per unit) by using an NSS LineGard 30 Amp GFCI. This is because the GFCI is in between the power source (the circuit board) and the application (the drying machine), so its value doesn’t have to equal the circuit's capacity, it just has to be equal to or less than the circuit's amperage capacity. We hope this information helps you decide on the right NSS product that fits your needs!

What is Nuisance Tripping?

Nuisance tripping is a perfectly named phenomenon, it is a nuisance when your appliance stops working properly while doing its job! But what is it specifically? Nuisance tripping is the unnecessary tripping of a circuit at the breaker when there isn’t a fault to create the trip. The trip is caused by the GFCI that protects you from electric shock, but it can stop the current when it doesn’t need to on some occasions. There are a few different ways in which nuisance tripping can be caused.

What are Common Causes of Nuisance Tripping?

There are quite a few ways in which your circuit will trip from causes that aren’t stemming from a plausible need to cut power to said circuit. Here is a list of some of the most common occurrences of nuisance tripping and why they happen.

There are quite a few ways in which your circuit will trip from causes that aren’t stemming from a plausible need to cut power to said circuit. Here is a list of some of the most common occurrences of nuisance tripping and why they happen.

Moisture: Moisture is one of the most common causes of nuisance tripping. In wet and hazardous environments (where GFCIs are most needed), moisture can cause a trip even when there isn’t a fault in the circuit because water intrusion can cause the electrical connections in the equipment to malfunction. This is why if you are operating in a wet/hazardous environment you need a GFCI that has a high intrusion resistance (such as a NEMA 4X or IP 69 K rated GFCI).

Grounding Issues: If the appliance that is being GFCI protected is not properly installed or maintained, then this can cause the GFCI to trip even though there isn’t a fault due to incorrect communication between the receptacle providing power to the appliance and the GFCI.

Overloading: Overloading a circuit is another common cause of nuisance tripping. If there are too many appliances in a single circuit being protected by a single GFCI, then the circuit can trip even though there is no actual fault occurrence.

Old/Faulty Equipment: Sometimes older equipment is susceptible to corrosion due to repeated use or harsh weather conditions. Once this equipment is to the point where it is past normal/safe operating function, it can cause the GFCI protecting the equipment to trip even though there is no fault in the circuit.

Voltage Spikes: Applications with an electric motor involved (such as compressors, alternators, fans, etc.) can cause GFCIs a problem with handling the start-up and wind phases of the motors operating cycle. This is because it adds a lot of extra “noise” (electrical current in the circuit) that is only present during the isolated period of time, but this added noise can cause a GFCI to trip a circuit.

While There are certainly more causes of nuisance tripping with a GFCI because of occurrences in a given circuit, these are some of the most common reasons why they occur. While they may not be easily fixable, it is always good to fully understand how to overcome each nuisance tripping situation so that your appliances can run uninterrupted in the future. There can be a plethora of ways to do this, such as making sure that you have a particle resistant GFCI when you are working in a wet environment, such as a food processing plant that performs washdowns to clean areas, so that moisture won’t cause unnecessary tripping of important appliances.

VFDs disrupting GFCIs

Variable frequency drives (VFDs) don’t always play nice with GFCIs when they are involved in the same electrical circuit. It can happen for a number of reasons, so let's take a look at what exactly a VFD is and how it can disrupt a circuit it shares with a GFCI.

What is a VFD?

A variable frequency drive is used as a controller for an electric motor. It controls the motor system by varying the voltage/frequency of electrical power in which it is supplied. VFDs also help control the large amount of “noise” (high-frequency electrical power spikes in the circuit) in a circuit during the start-up phase when the motor is turned on and wind-down phase when the motor is turned off.

Why do GFCIs and VFDs have a resistive fit?

As we stated before, a circuit that involves both a GFCI and a VFD usually runs into a lot of problems. There can be numerous reasons, but here are a few of the most common:

  • Leakage Current: VFDs can produce high-frequency leakage currents during the start-up and wind-down phases of the electrical motors system that can cause a GFCI to trip. These leakage currents will travel through the ground path of the electrical system, which a GFCI will pick up and trip the circuit, thinking there is a fault.

  • Capacitive Coupling: When VFDs create high-frequency noise in the circuit, it can convert leakage of that noise to the ground wire. When the GFCI picks up this added noise on the ground wire, and if it is at a high enough frequency the GFCI will trip the circuit.

  • Voltage Spikes: As explained in the short paragraph above, during the start-up and wind-down phases of the electrical motor the VFD will create considerable noise in the circuit. This causes GFCIs to see this noise as a fault in the circuit if the surge in power is over the electrical circuit’s capacity (plus the GFCIs leakage threshold).

  • Incompatibility:Some VFDs construction is just simply unable to coexist with a GFCI. Whether it is a difference in the grounding systems, the VFDs specific power electronics, or the specified control system in the VFD can make it too complicated in a circuit with a GFCI (and vice versa).

All of this information isn’t to say that VFDs and GFCIs are completely incompatible. There are some VFDs that work seamlessly with GFCIs in certain circuits, it honestly is determined on a case-by-case basis. There are some productive steps to take if you are trying to protect your motor that has a VFD with a GFCI. The first is to figure out if the manufacturer of that specific VFD has created their product with ground fault protection in mind. It is also good to test (or have an electrical contractor test) how large the amount of leakage is involved with the motor to see what level of GFCI protection can be used on that motor (if it is consistently over 6mA, then looking for a Class C GFCI or and elevated trip ELCI might be the best course of action).

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