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Comment by klodolph | Hacker News Reader

“GFCI” is maybe a bad name because it describes what the system is supposed to accomplish but not what it does.

It interrupts the circuit in response to a current imbalance between hot and neutral. Kirchoff’s laws… if the current is imbalanced, it must be going somewhere else.

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New homeowners: Know where your GFCI reset switches are located.

I just had a fun time debugging why some of my outlets weren't working. Turns out there was a GFCI tripped in the garage, a few rooms down from the outlet.

I have never seen a GFCI reset switch in a different room from the outlet. I’m not surprised it exists, but it would make me unhappy.

In France (and apparently the rest of Europe too) our GFCIs are not located at the outlets. They are inside the electrical panels and protect a row of circuit breakers.

I've seen builders put the all the outlets for bathrooms on one circuit with the GFCI in one bathroom - typically the master bath. In my last house the outside outlets were on the GFCI with the outlets in the garage. Anything to save a few bucks as long as code allows it.

You can daisy-chain the rest of the outlets in a circuit off of a single GFCI. They have two sets of terminals -- one for the leg of the circuit that goes to the breaker panel and the other for attaching the rest of the circuit.

GFCI outlets have two sets of terminals, line and load. Line is meant to take hot & neutral from the mains panel. For load, you can run wire from there to downstream regular outlets, and it will give them GFCI protection too.

This is annoying when the outlets are in different rooms and it's not clear what's connected to what, but can save money when wiring up a bunch of outlets in a kitchen, for example, since a GFCI outlet can be $20 or more, while regular outlets usually only cost a couple bucks.

At a previous rental, we had an outlet in the hallway that never worked -- only upon moving out did I discover the GFCI outlet hidden in the back of a cabinet in the adjacent bathroom.

I've had the GFCI switch in the main fusebox in a couple of modern-ish apartments. That seems a perfectly sensible place for it, it's where you'd go to check whether the room breaker had tripped anyway.

That complicates things a bit in the panel because the breakers need a connection to neutral, but yeah, otherwise a slick setup.

Newer panels and breakers are plug-on-neutral, older breakers have a pigtail to the neutral bar.

My house came with an EV charger wired through a GFCI breaker. That damn thing tripped constantly because I guess it was malfunctioning? And they are quite expensive for a 50A version.

Or maybe the charger was badly wired and the breaker was preventing it burning down your house?

I spent a whole night worried about electric hazards when the meat smoker killed an outlet outside my basement door. My wife's aunt, an electrician, asked if we checked the GFCI. I had read about it online, but didn't find the switch near any of the outside outlets. Nor was it by any of the inside outlets on the opposite side of the wall from the outside ones. Turns out, it was in the upstairs bathroom. Because why not?

We call them 'Residual Current Devices' elsewhere in the world, which is at least a bit more accurate.

Technology Connections has a good video on the topic, but you probably already knew that.

Most of my electricity / electronics knowledge comes from books and old forum posts. I would have loved Technology Connections if it came out when I was younger.

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