GFCI Risks? Update

[BFL13]

Updated 24 March
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Having a new GFCI problem I have been unable to locate in the "receptacle circuit".

While on shore power (from house) The GFCI receptacle on that string itself had power, showing two lights on the tester as "normal", but the GFCI was popped and would not reset. The rest of the receptacles all dead.

The other 120v circuits in the trailer, including the GFCI "galley" receptacle on its own cicuit are ok.

Swapped over to inverter with shore power plugged into that, and now the receptacle circuit is fine and the GFCI button can be reset so everything seems ok. Back to shore power and not ok.

To get a quick fix, I took out the GFCI receptacle and replaced it with an ordinary one, so now everything seems ok even when plugged into the house.

However, whatever was causing that GFCI to pop is still there of course. I checked for that by plugging the trailer into the house bathroom GFCI receptacle and it popped.

So just what is the risk here? If I don't plug into a shore power GFCI receptacle, I would never know, and when off-grid on inverter I would never know.

Hunting for that GFCI would take hours and hours taking out each receptacle I guess, since the usual swapping things around didn't find it. So until I get that ambitious, should I care?

Thanks

[BFL13]

Apparently I had the two sets of wires going into the top and bottom receptacles of the GFCI gizmo reversed according to an earlier post, explaining why it still had power although popped.

So it did work anyway to indicate there is a fault and shut down the other receptacles on that circuit, but it stayed on, which was wrong, and would not reset even though it had shore power. It did reset with inverter power (inverter not bonded but the shore power from the house is bonded at the house panel as I understand it )

That must have been me that got it wired backwards some years ago when I had another GFCI fault and I had that whole GFCI receptacle out and put it back in after finding it ok when tried in another circuit. That time it was a wet outside receptacle.

I will get it right this time around!

Meanwhile that circuit still has a fault in it somewhere that I have to find, but I am not in a rush- have other work to do first. (So don't expect any follow-up soon on what the fault turns out to be)

With the help in this thread I have learned some more about GFCIs and should be able to chase this down. Thanks for your interest everybody.

[Gdetrailer]

DrewE wrote:

keepingthelightson wrote:
IF you are connecting the shore power cord to a GFCI outlet on your house and you are expecting the GFCI in your trailer to work. IT will not. You CAN NOT have two GFCI on the same circuit in parallel. You need to remove your GFCI from your shore power at the house.

Good luck! 😉

35 yrs. electrical experience.

That makes absolutely no sense to me. A GFCI works by measuring the current difference between the hot and neutral legs, and tripping if it exceeds some tiny threshold. (The sense of the current is, of course, opposite—hence it's okay so long as the current flowing through the hot all returns via the neutral).

You can't have a GFCI wired such that there's a neutral return path separate from the GFCI, whether it's through another GFCI or not, but that's a different matter entirely. Connecting one GFCI to the load terminals of another is not problematic and indeed happens quite frequently—air dryers, for instance, have GFCI's built into their cord sets (required since 1991), and are commonly plugged into GFCI-protected outlets in bathrooms.

Edit: I guess apparently hair dryers may have immersion detectors rather than GFCIs in their cordsets, which is not quite the same technology, but the basic electrical facts remain.

"Immersion" detector IS the same as a GFCI except for the fact that an immersion detector is a "one and done" non resettable version of a interrupter.

Initial function is the same between both but the idea behind the Immersion version is to prevent you from operating a device that may have been immersed in water ever again to protect you from your own bad judgement (I would have never thought to plug in anything that was dunked in water without inspecting the inside for damage)..

Immersion detector

IMMERSION DETECTOR FAQS

Conair® manufactures its hair dryers with two different kinds of safety plugs. The ALCI is known as an Appliance Leakage Current Interrupter. This unit has the Reset button and the Test button. The circuit is looking for leakage of current between the two conductors. This unit sometimes trips when lights are turned on and off, when the dryer is plugged in, or when a new dryer is taken out of the box and plugged in by the consumer who doesn’t know how to operate the Reset feature. An IDCI refers to Immersion Detector Current Interrupter. This unit trips only when the dryer has been immersed in water. The dryer should never be used again after immersion because of the potential dangers a water-damaged unit presents to consumers. That is why this unit trips once and is not resettable - because it shouldn’t be used again! Both safety plugs look a little different but they provide the same function - they protect the consumer from electric shock.

IMMERSION DETECTOR PATENT INFO

When a small current passes between the sensing conductor and the ungrounded or grounded neutral sides of the line or earth ground, current is shunted through the detection circuit from the ungrounded to the grounded neutral conductor, and away from the appliance circuit. A fuse link is opened in one side of the line which, in turn, releases normally open contacts, in the other side of the line, which open and remain open, so that both sides are permanently interrupted.


As far as "multiple" GFCIs in the same circuit, it won't harm anything although not really a recommended thing to do since it may increase the chances of false trips on one or all the GFCIs..

Multiple GFCIs are done every day, look at wall A/C units, everyone that runs on 120V HAS a GFCI on it.. You CAN plug it into an outlet protected by a GFCI outlet or circuit breaker upstream and it will work.

[enblethen]

OP also removed the rig's GFCI and it tripped the GFCI in the house.
He has a problem inside the rig.
Why the tester read good or the GFCI did not trip the feed is the big issue.
The three light tester shows the system to the GFCI as good when in fact the feed through function is not working.
OP did you check to insure the GFCI was wired correctly? Don't trust the label! Brass colored screw gets the hot wire, normally black and the silver screw gets the white wire.

[DrewE]

keepingthelightson wrote:
IF you are connecting the shore power cord to a GFCI outlet on your house and you are expecting the GFCI in your trailer to work. IT will not. You CAN NOT have two GFCI on the same circuit in parallel. You need to remove your GFCI from your shore power at the house.

Good luck! 😉

35 yrs. electrical experience.

That makes absolutely no sense to me. A GFCI works by measuring the current difference between the hot and neutral legs, and tripping if it exceeds some tiny threshold. (The sense of the current is, of course, opposite—hence it's okay so long as the current flowing through the hot all returns via the neutral).

You can't have a GFCI wired such that there's a neutral return path separate from the GFCI, whether it's through another GFCI or not, but that's a different matter entirely. Connecting one GFCI to the load terminals of another is not problematic and indeed happens quite frequently—air dryers, for instance, have GFCI's built into their cord sets (required since 1991), and are commonly plugged into GFCI-protected outlets in bathrooms.

Edit: I guess apparently hair dryers may have immersion detectors rather than GFCIs in their cordsets, which is not quite the same technology, but the basic electrical facts remain.

[ken_white]

keepingthelightson wrote:
IF you are connecting the shore power cord to a GFCI outlet on your house and you are expecting the GFCI in your trailer to work. IT will not. You CAN NOT have two GFCI on the same circuit in parallel. You need to remove your GFCI from your shore power at the house.

Good luck! 😉

35 yrs. electrical experience.

The GFCI devices are not in parallel, they are in series.

House GFCI (H) -> camper connection -> camper branch circuits and returns back through camper branch circuits -> camper connection -> House GFCI (N) so the currents should balance unless somewhere along the line it leaks between neutral and ground.

[keepingthelight]

IF you are connecting the shore power cord to a GFCI outlet on your house and you are expecting the GFCI in your trailer to work. IT will not. You CAN NOT have two GFCI on the same circuit in parallel. You need to remove your GFCI from your shore power at the house.

Good luck! 😉

35 yrs. electrical experience.

[wnjj]

BFL13 wrote:
Aha thanks! I will swap those when I put a GFCI receptacle back in there.

Rather than just swapping, connect only the line terminals and then see if it powers up. If it works, turn off the breaker and then hook up the load side.

Another possible cause could be the ground wire vibrated its way over against the neutral screw on one of the downstream receptacles. Unfortunately you'll have to start pulling those to look. You can always divide and conquer by cutting half of them out of the circuit to see where to look next.

[mena661]

I had a similar problem (ie. the same problem) and it turned out to be my converter.

[westend]

Have you checked the integrity of the load center buses recently? It may be possible that corrosion or a loose wire in the load center ( in the circuit powering the faulted GFCI). Something like that would allow other GFCI devices in a different circuit to work correctly and the one circuit to fault.

[BFL13]

Gene&Ginny wrote:

BFL13 wrote:
... Hunting for that GFCI would take hours and hours taking out each receptacle I guess, since the usual swapping things around didn't find it. So until I get that ambitious, should I care?...

YES

At least I didn't cut off the ground prong on the shore power cord to make the problem go away.

Instead I got rid of that pesky GFCI receptacle! "Shoot the messenger" works for me 🙂

[Gene_Ginny]

BFL13 wrote:
... Hunting for that GFCI would take hours and hours taking out each receptacle I guess, since the usual swapping things around didn't find it. So until I get that ambitious, should I care?...

YES

[Gene_Ginny]

BFL13 wrote:
... I was surprised when the GFCI receptacle was popped, that it still worked and showed the two lights for normal on the tester, but the rest of the receptacles did not work. I somehow thought that GFCI receptacle would also be dead when it is popped.....

It should be dead when it "popped". It sounds very much as if the Line an Load were reversed. When that happens you can not reset it.

See Previous post by Paul D.

[Paul_D_]

If you are going to replace the gfci , read the labels carefully. There has been a manufacturing change:
The "line" terminals are now at the top and the "load" terminals at the bottom near the ground (green) . As pointed out by an above respondent the polarity on these is critical for proper operation.

If it does turn out the fault is on the "load" side of the receptacle; at least you have a good idea where to look as they are the devices that are off when the gfci trips.

When using a core with a "polarized" 2 prong end ( like a hair dryer) the gfci my not trip if no path to ground exists. For example if the dryer falls in a plastic tub of water with plastic pipes.

[Dusty_R]

Bobbo wrote:
GFCIs do go bad. Yours did.

I once replaced a full size upright deep freeze, only to find a bad GFCI outlet. DW was NOT happy.

Compressor type refrigation equipment and GFCI's do not get along well. Best not to plug a refigator/freezer into a GFCI receiptical.

[BFL13]

Bobbo wrote:
GFCIs do go bad. Yours did.

I once replaced a full size upright deep freeze, only to find a bad GFCI outlet. DW was NOT happy.

Did that put you in the dog house? 🙂 ( Not that our agility dogs have to live in such things)

Executive-- thanks, I will check that too.