GFCI sensitivity issues

[JHZR2]

Living in an old home, some wiring is a little funny... One of our bathroom vent fans is fed off a circuit in an adjacent room. The fan is fed via a switch loop, from a line in the wall which feeds an outlet.

I checked the codes, and this is a suitable way to operate, where essentially the plug (GFCI by code) is fed, then feeds the fan, which has a switch loop to turn it on. The circuit is ungrounded, which is part of the reason why the gfci is necessary.

We had an old GFCI, I anticipate it was what was originally there when the bathroom was redone in the 70s or early 80s. The outlet color was wrong and one of the outlets was stiff, so I replaced it.

Since then, maybe once a month, the gfci opens up and the fan won't operate until I reset it. I've been able to isolate it to the point where I find that the gfci will open at shut down / turning the fan off

The old gfci did work in gfci duty. I verified that. The new one does as well. But the old one never caused an issue with opening due to the fan operation. I suppose the old one may have been less sensitive, perhaps even a mechanical variant, I don't know.

This issue happens at most maybe once a month. I'm not sure why it occurs. Any thoughts?

Thanks!

 

[oldhp]

Old fan motor grounding? Did you check ohms on the feed wires?

 

[Quest]

fan motor winding maybe dubious in terms of current leaks....

Also: for GFIC, because most of the national brand names such as Leviton, etc. are now made in china, I encountered maybe 1 every 5 to 10 units that deemed somewhat overly "sensitive" to even properly insulated/tested fan or light units....the only way to find out is to try a different brand (e.g. Pass & Seymour) and see if that same phenomenon happens.

If it does, your bathroom fan is in question. I would not hesitate to replace that fan.

Q.

 

[mattwithcats]

There are ways to wire a GFCI so it feeds an outlet (or device) without acting as a GFCI to the upstream outlets / devices.

Look on the back of the GFCI, (with the power OFF!), there should be a passthrough diagram, or in the box.

If all else fails, take the incoming, a short stub of wire, and the fan wire and use a wire nut to put them together.
Do this for the hot, neutral, and ground.
Now run the stubs to the GFCI...
GFCI is out of the fan circuit...

 

[mattwithcats]

On the back of the GFCI, there is the top half, with one screw for hot, and one screw for neutral.

bottom half is the same way, a screw for hot, one for neutral.

If you use the top and bottom, incoming on one, outgoing on the other, the GFCI is in the circuit. Fan shuts off when GFCI trips..

If you put the incoming power and fan wire together on one screw (I use the little holes in the back), then the GFCI is out of the circuit. Fan stays on when tripped.

 

[Corvette Owner]

Check and make sure that gfci does not service an outside outlet, if it does, check on that outlet after rain, by using a leaf blower to dry it out. If this is an issue, you probably have to replace the outside gasket.

 

[mattwithcats]

Use a Weather Resistant GFCI if it's outside...

www.leviton.com/OA_HTML/SectionDisplay.jsp?section=42320

They have a "WR" printed on the front...

 

[ironman_gq]

Originally Posted By: mattwithcats
On the back of the GFCI, there is the top half, with one screw for hot, and one screw for neutral.

bottom half is the same way, a screw for hot, one for neutral.

If you use the top and bottom, incoming on one, outgoing on the other, the GFCI is in the circuit. Fan shuts off when GFCI trips..

If you put the incoming power and fan wire together on one screw (I use the little holes in the back), then the GFCI is out of the circuit. Fan stays on when tripped.


They don't recommend you use the push locks on the back because they loosen up over time and can cause issues. There should be a pass through wiring diagram that will allow you to wire non-gfci devices to a gfci outlet.

 

[kschachn]

Who doesn't recommend it, the GFCI manufacturer? If so, then I would think that UL would like to know.

Originally Posted By: ironman_gq
They don't recommend you use the push locks on the back because they loosen up over time and can cause issues. There should be a pass through wiring diagram that will allow you to wire non-gfci devices to a gfci outlet.

 

[JHZR2]

Thanks all. This has nothing to do with outside, and there is a reason why a gfci is used in this application, so I'm not interested in bypassing it.

Fan is fairly new, like say, less than seven years. Switch for the fan is older and may be dirty or part of it.

The circuit is ungrounded, which is part of the reason why a gfci is used.

I too have had hit or miss luck with some of the big name stuff, so that's definitely in play too...