gfci question

Will subject device trip on a short as well as a ground fault? Seamus J. Wilson
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Hi Seamus,
The information presented here should help answer your question.
http://www.codecheck.com/gfci_principal.htm
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Thank you for the informative reply. Best, Seamus J.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

I suppose anything's possible, but I would say no. A short is not a ground fault.
I've shorted GFCI circuits in the past and the outlet has never tripped.
-Tim
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
sligo wrote:

If it's a GFCI "outlet" it shouldn't if the short is only between hot and neutral.
If its a GFCI "breaker" in a panel, then it of should trip on a short of low enough impedance to cause the current to exceeed the breaker's trip level.
Jeff
--
Jeffry Wisnia

(W1BSV + Brass Rat \'57 EE)
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Could you elaborate? Is it that the insulation on the wires inside will be damaged by the high pressure, or that you'll just end up wedging some dust/dirt in even deeper, where it will cause more damage?
Cheers, Wayne
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

No, replace it with a standard outlet and you'll be hiding the problem. The problem will still be there, and if it becomes worse, could become dangerous.
Cheers, Wayne
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Agreed. The OP is being wise IMO. While one sees GFCIs not recommended for other circuits that supply motors; fridges etc. the fact that it worked OK for many years and now doesn't seems to indicate the OP is doing the right thing to question and check.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Thanks for everybody's input.
I replaced the GFI today and still have the same problem. I'll try cleaning the motor (with compressed air!) and see if that works. TS Fay has dropped a foot of rain around here the last four days, and though the wires and motor are protected, maybe there's dampness I can't see.
I'll let you know if it works.
unklerichie
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Sat, 23 Aug 2008 15:07:33 -0700 (PDT), unklerichie

I'm about the furthest thing from an expert, but for clarification, the fan is on the same circuit as the GFI's, but not plugged into the GFI, right? Are there other loads running on the GFIs when they trip?
40" fan is pretty big, it could just have a big, fat turn-on surge, but how long as this been going on? And is the fan plug two or three prong (presume three). And have you checked the ground to the fan outlet?
J.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
It is odd that the GFI trip 10 seconds after the fan is on. Perhaps it has become unbalanced, and when it is up to speed it vibrates so much something gets shorted?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

To answer a couple of your questions... My fan has no plug on it. It's wired from a wall switch. I have other things running on the same circuit (a few outlets and an 8' fluorescent shop light). My fan trips the GFI whether there are additional loads on the circuit or not. It doesn't seem to make a difference. I used my compressed air to blow out the motor and it didn't help. When I first posted, I mentioned that the fan would run for ten seconds and then trip the GFI. The 'ten seconds' only happened the first couple of times I tried it. Since then, it trips immediately. I think I've successfully ruled out the GFI (replaced), the wall switch (replaced), and the wiring from the GFI to the switch to the fan (all closely inspected). I suppose it's time to have the motor serviced. If anyone is interested, I'll post the outcome later.
Thanks for everyone's help.
unklerichie
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Sat, 23 Aug 2008 13:56:44 -0700 (PDT), terry

I thought it was only fridges and freezers, because when they lose power the food rots, and maybe some other situations like that, but not motors in general.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Hello everyone.
I removed the fan motor and tested it on the benchtop. It's definitely bad. I replaced it with a 1/2 hp motor I had laying around (original was 3/4 hp), same rpm's, but the 1/2 has a heck of a time getting the fan moving. I don't know enough about motors to attempt that repair myself.
So I decided that's enough of this project. Despite everybody's assistance, I gave up, went on Grainger's site and ordered a new fan. The new ones are so much more efficient (much more cfm's at lower rpm's) , 2 speed, and the one I ordered includes a shutter, a luxury I don't currently enjoy.
Thanks group!
unklerichie
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

That's why there is a (fairly expensive) device called a megaohmmeter or "megger" which will apply a selectable DC voltage (e.g. 300V or 600V) and measure the resistance. Using it between the hot and frame of a motor is a good way to test for insulation degradation in the motor windings. (Never use the megger between the hot and neutral of an appliance or load, they aren't designed to run on 300V DC!)
Cheers, Wayne
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Related Threads

    HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.