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In North America, I'm told GFCI outlets have become common. They have an individual differential circuit breaker built-in.

In the European Community, differential circuit breaker are (mandatorily) installed on the electrical distribution board. GFCI and differential circuit breaker

What are the pros and cons of each from an electrical engineering standpoint?

Safety is one (but not the only) concern. On this standpoint I can think of:

  • A central differential circuit breaker triggers if there's a ground leak between it and the plug, a GFCI outlet does not.
  • It's almost impossible to miss-wire a GFCI outlet in a way such that what's plugged works even once, and the miss-wiring is an electric shock risk in case of ground leak downstream the plug.
  • GFCI outlets are more likely to be regularly tested by end users.

Anything else, including on cost?

Note: There is no choice to be made from a practical standpoint, since that's governed by mandatory regulations in all places I know. I'm not familiar with the regulations, exact vocabulary, class of differential circuit breaker (I barely know there are different kinds, and uncertain about their rationale; though I can understand that loads and/or ground fault currents with a strong DC component are a possibility, and have the potential to create special requirements).

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    \$\begingroup\$ This question might be better suited to diy.stackexchange.com \$\endgroup\$ May 30, 2021 at 11:31
  • \$\begingroup\$ @Bimpelrekkie: this is not a DIY question: there is no choice to be made from a practical standpoint, since that's governed by mandatory regulations in all places I know. \$\endgroup\$
    – fgrieu
    May 30, 2021 at 11:54
  • \$\begingroup\$ I would move it to the DIY group. You're more likely to get relevaant information there, \$\endgroup\$
    – SteveSh
    May 30, 2021 at 12:01
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    \$\begingroup\$ Related: diy.stackexchange.com/questions/102905/… \$\endgroup\$ May 30, 2021 at 13:52
  • \$\begingroup\$ For what it's worth, I'm in the US and around here new construction typically uses AFCI/GFCI breakers at the panel rather then at each outlet. I think it varies widely based on local code. \$\endgroup\$ May 30, 2021 at 13:57

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You speak of GFCI (I had to google it: it means ground fault circuit interrupter), as if it is equipped with a zero-sequence or differential circuit breaker, protecting against "ground leak"; during my internet search I have found instead "ground fault" mentioned, as if it protects against short circuit, not leaking.

Let's assume that it is like a RCCB in the IEC/CENELEC jargon (RCCB = residual current circuit breaker). It is utmost useful in a range of situations/applications: bathrooms, dish washer, places with humidity (basement, garage), etc. where leaking is quite likely sooner or later, and a person might be in a "disadvantageous resistance situation", that means wet contact, no good isolation, possibly many conductive parts nearby, weak person (not a well equipped worker).

About guarantee of protection compared to traditional circuit breakers (maximum current), it is a bit involved, because standards are traveling at one pace, local regulations at a different one (snail like). In general, when you have TT distribution your short-circuit loop impedance is larger (you are far away from the power source, you rely on local grounding): an RCCB is a must, and it is allowed, or better advised (see e.g. BS 7671 and IEC 60364-4-41). In TN systems it is not strictly necessary for protection and this is confused with "it is sufficient": it works, it's strongly advisable, but please put a magnetic circuit breaker upstream for short-circuit current.

Nowadays this stuff is not expensive, so again highly advisable.

Cons: there are different types**, sensitive to AC 50/60 Hz (mains), to DC, to -- in addition -- high frequency content. They are thus more complex and need some evaluation beforehand if your application is not a standard dish washer. For complex applications, where you have exigencies of protection and continuity of service (or availability), you should take a look at Residual Current Monitors (ref. std. EN 62020) and Residual Current Circuit Breakers (ref. std. EN 60755, E 62423). Strange applications I work with are: signaling and control implementing safety functions, such as point machine in railways, signals especially in metros (IT systems quite diffused in US and Canada), etc.

**the mentioned types are e.g. B and F, for which the EN 62423 speaks of "with and without integral overcurrent protection". So, the only problem is that they are not a straightforward solution, with one medicine that cures all ills.

Following Transistor's hint, comparing a RCCB in the main switchboard to RCCBs locally deployed at sockets:

  1. A single RCCB at the main board must be selected/trimmed for a higher leakage current, so less selective.
  2. A trip will switch off everything (selectivity problem), even when the trip is caused by one specific load such as a conditioner or a fridge with large dispersion through the cooling serpentine.
  3. Such RCCB+outlet are not expensive, so they can be deployed at the most troublesome loads, and they will protect just that, with beneficial continuity of service for the rest of the system.
  4. As said, a local RCCB+outlet can be tailored to a lower leakage current, thus making protection more effective, especially for situations of critical exposure.
  5. RCCB at outlet is not so different from protecting selectively downstream lines at the main board: the only "con" is that you have to check locally what is the outlet that has tripped, but it's you home or office, not a 10-acre plant (centralized monitoring is a second-order exigency).

All in all, highly advisable, not expensive, and the only caveat is to take care of untimely triggering and suitability for specific applications.

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  • \$\begingroup\$ I think the question is, "What are the advantages and disadvantages of (1) having a RCCB in the main distribution panel (2) having them on each wall socket." I think you may have missed it or not answered it clearly. \$\endgroup\$
    – Transistor
    May 30, 2021 at 12:05
  • \$\begingroup\$ @Transistor I will edit the answer trying to make it clearer. \$\endgroup\$
    – andrea
    May 30, 2021 at 12:24
  • \$\begingroup\$ No problem. I see the OP has added some photos of the two types of devices. \$\endgroup\$
    – Transistor
    May 30, 2021 at 12:31

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