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Looking at the North American electrical regulations, I come across the concept of GFCI protection in electrical outlets. In contrast, in the IEC regulations, differential protection is comprehensive and is required in the main electrical panel of residential installations. Does the North American regulation mandate the inclusion of differential protection in the main panel, or is it only required in electrical outlets in specific designated areas?

Can I avoid using GFCI outlets if I implement centralized differential protection?

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The rules are different; and the level of protection they provide is different.

One RCD to rule them all as per Europe has a trip sensitivity (typically 30 mA, IIRC) that is well in the "will kill humans" range. Lowering the trip sensitivity on a whole-house feed to the level used in North American "per circuit" GFCIs (5 mA) would result in excessive nuisance trips. As such, they trip for large enough earth faults (current going somewhere other than through the wires) but they permit earth faults at a level that does not generally protect against electrocution, if the cause of the earth fault is a human serving as the current path to earth.

The North American scheme can be "centrally" done in the sense of using GFCI breakers, but they are still "one per circuit" and as a rule they cost a lot more than a GFCI device that's not a breaker as the first device on a protected circuit. But both are acceptable per code. If you don't want GFCI receptacles, you can use GFCI breakers; for many circuits you'll now need combination AFCI/GFCI breakers to meet current codes.

GFCIs largely provide safety from electrocuting humans, and can be located as the first device on the circuit (without any special wiring consideration), or at the breaker. AFCIs provide safety from fires caused by sparking wires or connections. AFCIs either need to be at the breaker, or the wiring from the breaker to an external AFCI device needs to be contained in a grounded metallic covering (conduit or armored cable.)

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    I was guessing that the OP also isn't aware that ring circuits are forbidden in the US, which lets GFCI outlets protect downstream circuits, making using them somewhat less expensive than it may appear.
    – keshlam
    Nov 6, 2023 at 14:18
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    According to my electrical safety education from working in (and supervising students in) high voltage laboratories, 10-100 mA is the primary range of hazard. One factor is the inability to let go and stop the shock.
    – Ecnerwal
    Nov 6, 2023 at 16:26
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    Per OSHA: <1 milliamp=Generally not perceptible. 1mA=Faint tingle.. 5mA=Slight shock felt. Not painful but disturbing. Average individual can let go. Strong involuntary reactions can lead to other injuries. 6-25mA=Painful shocks. Loss of muscle control. 9-30mA=Freezing current or “let go” range. If extensor muscles are excited by shock, the person may be thrown away from the power source. Individuals cannot let go. Strong involuntary reactions can lead to other injuries. 50-150 ma=Extreme pain, respiratory arrest, severe muscle reactions. Death is possible. >1A: Heartbeat disruption.
    – keshlam
    Nov 6, 2023 at 18:46
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    Note that the cardiac risk depends on where the current is flowing, as well as how much. Across one hand may cook the hand but won't get to the heart. But if the current is flowing through/across the body...
    – keshlam
    Nov 6, 2023 at 22:27
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    To add to the discussion, another important point is that in the US the voltage is half of most of the rest of the world, including Europe. A lower trip current might also be dictated by the fact that there are several conditions in which a human touching a live wire will not draw anything close to the 30 mA, because of the lower voltage - but still you want something to trip. Nov 8, 2023 at 7:51
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Does the North American regulation mandate the inclusion of differential protection in the main panel, or is it only required in electrical outlets in specific designated areas?

The NA electrical code does not mandate where the GFCI protection device must be, only which outlets must have it. As a result the most common type or protection is at the outlet.

Can I avoid using GFCI outlets if I implement centralized differential protection?

yes, they make GFCI breakers for this purpose, they have a white pigtail that goes to the neutral bar and the neutral for teh circuit must land at the breaker as well. But be careful you don't mix them up with AFCI (arc fault) breakers which look almost identical but protect against a different electrical hazard.

You are allowed to have GFCI protection in places where it isn't mandated. Though regulations are evolving into expanding the places where it is required.

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  • Thank you for your question. To clarify, when you mention that "The North American electrical code does not mandate the specific location of the GFCI protection device, but only specifies which outlets require it," you are referring to the fact that the NEC doesn't prescribe the exact placement of GFCI protection within an electrical circuit. However, the most prevalent practice in North America is to use GFCI outlets at the point of use? Isn't using it in power outlets more expensive than a general one? Nov 6, 2023 at 14:11
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    @JuliánOviedo Price the two, and realize that you only need one GFCI device at the first receptacle location to protect all the other outlets on that circuit. Also see my answer regarding the fact that you need one GFCI device per circuit in either case, not one for the whole house.
    – Ecnerwal
    Nov 6, 2023 at 14:15
  • There are more factors there, one of upgrading existing installations where a neutral might have been "borrowed". GFCI outlet can also protect downstream outlets. The other is the convenience of being able to reset a GFCI trip without needing to go to the panel. Nov 6, 2023 at 14:16
  • Does the code specify which threshold should be used? In Europe 30 mA is common, like Ecnerwal says. Is that allowed in the US?
    – Orbit
    Nov 6, 2023 at 14:35
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    @Orbit In the US, GFCI trip current is 4-6 mA per NEC and UL 943. 30 mA+ trip devices are designated for equipment protection only (GFPE, Ground Fault Protection for Equipment) and are only required and found in industrial systems.
    – user71659
    Nov 7, 2023 at 15:41
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Under National Electrical Code, for locations where GFCI protection is required, it may be provided in any of several ways largely up to the discretion of the electrician or electrical engineer who designs or installs the electrical system.

  • At the outlet - a GFCI receptacle could be installed so that that single receptacle is protected
  • At the outlet - a GFCI receptacle could be installed so that it provides protection for that outlet and any outlets downstream
  • Before the outlet - a GFCI "dead front" device is packaged just like a receptacle, but it lacks the sockets on the front. These are used when GFCI protection is needed for some downstream device, but a receptacle at the location is unwanted.
  • Protect one circuit in a breaker panel - a GFCI circuit breaker can be installed in a circuit breaker panel to protect an entire branch circuit.
  • Protect an entire panel - a GFCI circuit breaker can be installed in a circuit breaker panel as a feeder protecting an entire downstream sub-panel.

This last one may be of particular interest to you. It was of interest to me too: I have a separate shop building at my home. Because it's a "garage" all of the 120 volt receptacles require GFCI protection. I have several 240 volt receptacles for portable equipment (welder, plasma cutter) where I also wanted protection (and I believe 2020 code now mandates it). Because of the size of the space there are several circuits for 120 and 240 receptacles. I didn't want to buy 5+ GFCI circuit breakers, so instead I bought two. One, a 20 amp single-pole, protects all of the lighting circuits (because the lights are cord-and-plug connected this is required). The second, a 50-amp two-pole, provides central protection to a subpanel. In that subpanel I can freely use ordinary circuit breakers for all the receptacle circuits because GFCI protection is provided by that feeder breaker.

I will mention that nuisance tripping of the subpanel feeder breaker has been a small problem. Maybe once or twice per year it trips. I have not yet made the effort to identify the cause. Maybe there is a single fault that should trip a GFCI no matter what - but maybe there are several small, normal leakages that would go undetected forever if not for the fact that I collected them all under one large GFCI breaker which still has just a 5 mA trip limit.

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  • Great answer. I must say that a 5 mA GFCI, especially with modern electronics, is truly a gamble :) You are lucky it does not instantly trip :) but of course it depends on what the sub panel feeds. Nov 8, 2023 at 7:58
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As noted in other answers you can put American style GFCI protection on branch circuits at the breaker panel.

To address part of your question, European style RCD protection in main or group breakers in the panel cannot typically be done in America. I don't know exhaustively but most residential breaker panels do not have available RCD main breakers and cannot accommodate group breakers the way European panels can. (In Europe you build group buses with little spade blocks, in North America the only bus is part of the panel)

I think this is what your question means by "centralized". Simply moving GFCI devices from the outlet to the panel does centralize them physically but it's expensive and inconvenient and probably not what you are getting at.

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    With the AFCI requirement, it's cheaper to have the GFCI at the panel since you need electronics and the trip mechanism anyway. From a quick look at big box prices, adding GFCI to an outlet adds about $11, going from AFCI breaker to dual-function adds $4.
    – user71659
    Nov 7, 2023 at 15:26
  • @user71659 good point, you can have your cake and eat it for $4, low-trigger GFCI (almost) everywhere without the problems caused by grouping together large numbers of circuits on RCDs. I really wonder though given the high cost of AFCI breakers, why no manufacturer is pushing a European-style panel where functions other than overcurrent are provided in groups of circuits to reduce cost and add flexibility.
    – jay613
    Nov 7, 2023 at 15:46
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This was mentioned by @GregHill and it's important to consider: where the circuit reset is located makes a difference in usability.

GFCIs aren't required by code because they make everything more complicated and expensive. They're required to save people. (This was covered extensively in others answers and comments.)

Ordinary breakers trip on a condition that many of us are very accustomed to avoiding: over-current circuits. GFCIs (newer) trip on some more subtle and harder to avoid conditions. AFCIs (newer still) trip on conditions that are even more subtle to the end user. Technology, with code following, has been adapted to make us safer.

When the GFCI does what it's supposed to and trips due to a detected fault to ground, one fixes the situation then resets the circuit. Depending on how and how much you use your kitchen or bathroom, this may happen rarely, or it may happen often. Likewise, it may happen often with outdoor appliances or in a garage or shop.

When it happens, how much effort you must go through to reset the interrupt could make things very irritating. Having the reset on the outlet that tripped, or very nearby, can be super handy. Going to a master panel to operate a GFCI-on-breaker could be a serious nuisance.

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