How are ground fault mini-breakers wired ? Are they even mini-breakers at all?

[Poodle Head Mikey]

This breaker is single-pole-sized and appears to only snap onto one buss bar in the panel. It had one full-sized single pole breaker looking 'switching handle' on it.

But . . . it has two screw terminals - and so in that regard looks like the output end of a mini-breaker.

Under the twin screw load side terminals there is a white wire coming out. This lone white wire goes to the neutral/ground connection terminal buss.

There is a freezer drain line heater wired to this breaker. Both sides of the drain line circuit are wired to the two terminals on the breaker. This seems like it cannot possibly work as the potential would be the same on both sides of the circuit.

Ahhhhh . . . . but it Does work - apparently because only one of the breaker's screw terminals have power. <g>

So anyway: wth am I looking at here? Is there supposed to be the same power from each of the output screw terminals? That is: 120 VAC to neutral? Mini breaker fashion?

Or . . . . is the second terminal actually a common connection - being made through that white wire going to the neutral/ground bar?

So? How do it work? <g>

[SBKold]

I cant comment on the science of it poodle but that white wire is how the gfci will sense the voltage to ground and trip.

[timebuilder]

What you are looking at is a typical gfci breaker. It compares the current flow in the white wire to the curremt flow in the grounding conductor, and if over 0.006 amps flows in the grounding conductor, this device will open the circuit power.

[Poodle Head Mikey]

So both the 120VAC leg and the Common leg are switched by the breaker?

And the common wire IS supposed to be connected to the breaker?

PHM
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What you are looking at is a typical gfci breaker. It compares the current flow in the white wire to the curremt flow in the grounding conductor, and if over 0.006 amps flows in the grounding conductor, this device will open the circuit power.

[timebuilder]

Yes.

The common goes to the breaker just like the feed.

Then, the common comes OUT of the breaker (it's another white wire, usually coiled like a pig's tail) and then THAT common goes to the neutral buss.

[lytning]

Didn't think the common is switched. I thought the white wire went through a currant transformer thinge.


Yes.

The common goes to the breaker just like the feed.

Then, the common comes OUT of the breaker (it's another white wire, usually coiled like a pig's tail) and then THAT common goes to the neutral buss.

[timebuilder]

Correct.

I didn't say common is switched. It is attached to the breaker in the same manner as the feed wire.

Internally, the common current is measured, and it continues to the neutral terminal block via the coiled white wire coming out of the breaker.

[Poodle Head Mikey]

I am not a fan of ground fault breaker or receptacles. They always seem like far more trouble than they are worth.

Thanks for your help. I guess the easy repair is out now - I'll have to crawl around in the ceiling and figure out what the electricians did wrong. They installed new door lights on all the display wall doors - and the next day all the door heaters weren't working.

A mere coincidence the electricians say - as they didn't work on anything which could have caused that problem.

[timebuilder]

I'm told the gfci receptacles have a 10% failure rate out of the box.

[Poodle Head Mikey]

In my entire lifetime I have only very rarely been shocked by a 120V circuit and not even in a single instance have I died as a result. And I don't know anyone, or even of anyone, who Has been killed either. GFI seems like a solution in search of a problem to me.

[SBKold]

In my entire lifetime I have only very rarely been shocked by a 120V circuit and not even in a single instance have I died as a result. And I don't know anyone, or even of anyone, who Has been killed either. GFI seems like a solution in search of a problem to me.

What about the hair dryer in bathtub and extension cord in swimming pool urban legends?

[Poodle Head Mikey]

No one who lives anywhere near me can afford hairdryers, let alone bathtubs or swimming pools. Those legends are probably just the way the universe weeds out the stupid-rich.

PHM
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What about the hair dryer in bathtub and extension cord in swimming pool urban legends?

[timebuilder]

Hundreds of people die every year from 120 volt shocks.

[ryan1088]

Sadly there were 3 or 4 deaths here last year from electrical shocks of improperly grounded/no gfci equipment on their docks. Sadly 2 of them were kids too.

[Poodle Head Mikey]

I'm not trying to argue - but I do point out that the odds do seem to be on my side. <g>

PHM
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Hundreds of people die every year from 120 volt shocks.

[Poodle Head Mikey]

And even beyond that; I am not advocating for the elimination of GFI. I say let everyone have all the GFI that they want or can stand. My objection is to someone mandating that I have to have it. I object both to being told how to run my own life, and also to the obvious implication that I could not manage to do so on my own.

I have come to observe that most things which are sold on the basis of primarily Helping either me or the General Good are actually no such thing. Rather they are focussed efforts to make a profit at my expense. And, knowing my likely reluctance to participate; the sellers pre-emtively lobbied for (bribed into existence) the Force Of Law to be added to their persuasive abilities.

[DDC_Dan]

They installed new door lights on all the display wall doors - and the next day all the door heaters weren't working.

PHM, the GFCI works by comparing current flow through the hot with current flow in the neutral (that's why the neutral has to go through the breaker). If there is more current going out on the hot than coming back on the neutral (unbalance), then the GFCI assumes there is another path to ground carrying some of the current (like a person!) and it trips. If a load is hooked to the GFCI's hot but uses a DIFFERENT neutral, for instance, the GFCI will see an imbalance and trip. Look for this type of scenario.

[lytning]

This is true. I don't know of a damn thing we can do about I except vote everyone out and get an honest government, if there is such an animal .


And even beyond that; I am not advocating for the elimination of GFI. I say let everyone have all the GFI that they want or can stand. My objection is to someone mandating that I have to have it. I object both to being told how to run my own life, and also to the obvious implication that I could not manage to do so on my own.

I have come to observe that most things which are sold on the basis of primarily Helping either me or the General Good are actually no such thing. Rather they are focussed efforts to make a profit at my expense. And, knowing my likely reluctance to participate; the sellers pre-emtively lobbied for (bribed into existence) the Force Of Law to be added to their persuasive abilities.

[timebuilder]

By not adopting these regulations municipalities open themselves up to liability.

So the attorney advising the municipality says yes, you have to make sure that these homes are all using GFCI's because that's part of the code now.

[jnsrose]

PHM, the GFCI works by comparing current flow through the hot with current flow in the neutral (that's why the neutral has to go through the breaker). If there is more current going out on the hot than coming back on the neutral (unbalance), then the GFCI assumes there is another path to ground carrying some of the current (like a person!) and it trips. If a load is hooked to the GFCI's hot but uses a DIFFERENT neutral, for instance, the GFCI will see an imbalance and trip. Look for this type of scenario.

Ditto, did this in my own house. After replacing a perfectly good gfi I realized I had to run a new circuit.

[WyrTwister]

This breaker is single-pole-sized and appears to only snap onto one buss bar in the panel. It had one full-sized single pole breaker looking 'switching handle' on it.

But . . . it has two screw terminals - and so in that regard looks like the output end of a mini-breaker.

Under the twin screw load side terminals there is a white wire coming out. This lone white wire goes to the neutral/ground connection terminal buss.

There is a freezer drain line heater wired to this breaker. Both sides of the drain line circuit are wired to the two terminals on the breaker. This seems like it cannot possibly work as the potential would be the same on both sides of the circuit.

Ahhhhh . . . . but it Does work - apparently because only one of the breaker's screw terminals have power. <g>

So anyway: wth am I looking at here? Is there supposed to be the same power from each of the output screw terminals? That is: 120 VAC to neutral? Mini breaker fashion?

Or . . . . is the second terminal actually a common connection - being made through that white wire going to the neutral/ground bar?

So? How do it work? <g>

The Circuit Breaker picks up the " hot " from the loadcenter bus bar , as " normal " .

The white wire does go to the neutral bar ( the neutral bar and the earth ground bar are not the same , except on the service panel , and even then , usually only on older panels ) .

The " hot " wire going to the equipment / device goes to one of the screws and the neutral goes on the other screw . The equipment grounding conductor goes to the ground bar ( on newer panels , there is usually a separate earth ground bar and if it is the service panel , there is a bonding jumper between it and the neutral bar , and the earth ground bar is bonded to the metal can / enclosure or panel ) .

The electronics inside the GFCI CB monitor the amperage flowing through the CB in both the " hot " and the neutral . In normal circumstances , all the current " leaving " on the " hot " returns through the neutral . They balance out and the electronics are " happy " .

If you have a ground fault , some of the current going out on the " hot " is not coming back on the neutral . It is returning through one of many possible ground paths , one of which is the equipment grounding conductor . A GFCI device does not really require an equipment grounding conductor in the circuit to function , but I always run one .

The electronics sense the current imbalance and trip the GFCI CB .

God bless
Wyr