3

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.

  • Is the TEST button pushed in? The way the test works is by internally connecting (through a resistor) things that should not be connected to make sure it trips. If it's pushed in, you'll get false readings. – Nate Strickland Jul 11 at 20:37
  • i'm pretty sure it is.. so would that be it? the tester meter goes up just like it would if i were to just touch the terminals together, though.. wouldnt the meter be different if there is an actual resistor in there? – Max Jul 11 at 20:43
  • A lot of GFCI devices (all of them?) need to be powered in order to press the "RESET" button and have it stay pushed in. Any testing on the actual GFCI device might not give expected results until it's plugged in and reset. – JPhi1618 Jul 11 at 20:46
  • 1
    Because plugs are not designed/allowe/listed for solid wire. Plugs should only go on cordage, which are stranded wire by definition. – Harper Jul 11 at 22:36
  • 1
    yeah i was gonna replace that cable with some cord wire – Max Jul 11 at 22:56
6

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.

  • Once the outlet is connected to the wires in the wall (or plugged in in the OP's case) there will be continuity between ground and neutral because they are connected in your main breaker panel, but if the GFCI (or any other outlet) is just sitting on a table, they should not have continuity. I couldn't tell in the question exactly how the tests were being done. – JPhi1618 Jul 11 at 21:01
  • +1 for recommending that OP get the right materials and do this properly. – Nate Strickland Jul 11 at 21:28
  • @JPhi1618 Yes, LINE neutral to Safety Ground should measure out at a couple milliohms. Can't promise the same for LOAD neutral to ground because you don't know how the GFCI is implemented. Usually it's a very low impedance choke, but it doesn't have to be... – Harper Jul 11 at 21:53
  • well ok, i am gonna replace the romex with some actual cord cabling. and i also realised that the problem was because my wires were overlapping and rubbed the insulation away. i will make sure this doesnt happen again and also, my box is going to be mounted onto a wall. i will also go get a drawn box and follow the rest of your recommendations. – Max Jul 11 at 23:00
  • If it's going to be mounted onto a wall anyway, you should either run that Romex through the walls, or run it (or better, individual THHN wires) through some sort of surface mounted conduit, e.g. Legrand Wiremold, plain EMT, whatever. You can feed off a flush-mount box with a Wiremold starter box, or a plain EMT extension box. – Harper Jul 11 at 23:42

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.