Electrical – GFCI – should the neutral and ground have continuity

electricalgfciwiring

I have a thing I'm doing.. I won't go into detail, but I have a thing that is a yellow solid core copper cable with a hot, neutral and bare ground. one end is connected to a plug I wired (I'm using the cable thingy as a makeshift cord because I don't have an actual cord). The other end is wired to the LINE of a GFCI.

Just to make sure I had no short circuits before I was to install my thingy, I checked continuity between the Hot, Neutral and Ground terminals on the GFCI to make sure there were no shorts in my wiring. When I touched the HOT and NEUTRAL prongs, they had continuity. (my continuity tester is really just an ohmmeter). So did HOT and GROUND. I undid the plug and looked for shorts, and there were none. I put it back together and now I see that only the NEUTRAL and GROUND have continuity.

Is this a break in my cable shorting the two or is it a faulty GFCI?

No, this is not connected to the wall yet. This is an isolated circuit I was testing for continuity.

Please help – I don't want this to end up shorting the HOT and NEUTRAL again and start a fire.

EDIT: I was stupid in the plug and put the wires overlapping. The thing that clamps down ended up pushing insulation away and shorted the wires. I am not going to make that mistake again.

Best Answer

At least violate Code a little less

Putting a GFCI in a box on a cable is a codevio. Using Romex for cordage is a codevio. And using junction boxes for portable boxes is also a code vio, but let's at least use a tough box and a strain relief, eh? Here's what you need.

  • square steel junction box, 4" square, drawn one-piece (not welded 5-piece)
  • Strain relief that fits the proper cordage you go out and get right now (get 12/3 since in cordage, ground counts). I can't bring myself to link the cable clamp for Romex, because it's so wrong...
  • 4" square 1-device mud ring with at least 1/2" depth (plays better with Decora) again must be drawn not welded
  • Metal Decora cover plate - cut the screws short if needed (Decora = large rectangular opening)

Alternate: a drawn steel Decora junction box lid can replace the last 2. Even though it's tougher, I avoided it because you'll have to bend/break off the Decora cover plate ears, and that'll wreck the GFCI for use anywhere else.

Alternate: if you want to put a GFCI and feed another plain outlet for 4 sockets then use a 4-11/16" box and mud ring, otherwise it won't all fit. You can use a plain receptacle and normal/Decora split cover plate.

enter image description here enter image description here enter image description here enter image description here enter image description here enter image description here

GFCI's, thru continuity, and ground

Safety ground is continuous through a GFCI.

LINE neutral to LOAD neutral is not continuous.

LINE hot to LOAD hot is not continuous.

enter image description here

As you can see, both hot and neutral go through the mysteryworks of a GFCI device. (actually, that includes a set of relay contacts, and also a current-sensing inductor, so you may read an impedance near zero.) Needless to say, if the relay contacts are open, line-load will read as dead open... IIRC the GFCI also has some electronics between LINE hot and LINE neutral, so you may also expect some non-infinity impedance there.

Now, look close: you see that green "upside down T" where the ground wire branches into the GFCI? No, you do not see that "T"? There's a reason you don't: GFCIs don't connect to ground. GFCI receptacles do, but only for the sake of the receptacle sockets; the GFCI portion doesn't use it.

Related Topic