I just moved into an older house with many two slot receptacles. I’ve been slowly changing them over to three slot grounded receptacles (all have ground wires) and grounded switches, but have run into a problem. On one circuit some of the changed receptacles test fine and others test “open ground” on both switched and unswitched outlets.
I checked the breaker box and all is fine (ground wire is connected properly).
a. any suggestions on how to find where the open gound is?
b. should I just use GFCI. Easy but expensive.
Thanks,
Carlos
Replies
What kind of wiring system was used. Non-metalic (Romex), Armoured Cable (common called BX), conduit?
While conduit and BX have are grounded if properly installed they don't have ground wires, as such.
And if romex was used and it had ground wire in the cable grounded receptacles could be used.
So I wonder if there might be some upgrades along the way that was not carried through everyplace?
Bascially you need to find all of the devices on the the circuirt with the open neutral. Then trace if from box to box to find the problem.
"b. should I just use GFCI. Easy but expensive. "
Well a GFCI can also protect downstream receptacles if several problem receprtacles are on one circuit.
But you really need to check the needs for grounded receptacles.
Look at what you are plugging in and what part of thehouse.
Most household loads don't need grounded receptacles.
And where needed (computers, some A/V, refigerators, freezers, sump pumps) a true ground is needed.
And places like kitchen and bathrooms need GFCI's anyway.
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
Thanks for the reply.
The cable in NM with ground (grey outer cover). This one problem circuit has several deadend branches one of which I want to use for my computer.
Very low attic makes running new cable particularly difficult.
Anyone else out there have another suggestion?
For your computer you want to have a ground. I've got the same/different problem in this house. My wife works at home in her office and there are no grounds.
Maybe there is a junction box somewhere where the ground isn't connected properly? In the attic can you see where the wire from the receptacle you are troubleshooting goes? (into a switchbox or other receptacle?)One guess would be that if it is run from another receptacle, or at the end of a chain of receptacles, whoever was installing the 2-prong plugs just didn't bother to tie the grounds together in one (or all) of the previous boxes, because it wasn't being used.
Most likely the problem is a bad connection in one of the boxes.So as a start identify all the receptacles and lights (and switches) on that circuit.Then start going through the boxes..
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
Is it permitted to run a ground from a nearby newly installed line going from the circuit box to the several new receptacles in the room
to an older receptacle on a different ungrounded circuit in that room?
be 3 to 1 odds against
Acutally you can.This is about the only place where you can run a separate wire for a ground that either goes back to the ground electrode system or to another point (such as another box) with a ground as long as it finaly gets back to the ground electrode system. Most like at the panel.BUT that is only for upgrading old systems with non-grounding wiring. Not for repairing a broken grounding wire..
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
Well cool. I'll gladly payup on the odds for that bit of data. Thanks
Figure out the route the wire takes as it daisy-chains from box to box. (Hint: Open boxes and see how many wires enter/leave. The end box will only have one romex entering, and you can generally figure that others daisy-chain left or right from there, so long as there are no boxes with 3 romexes.)
Assuming there's only one fault, it's somewhere between the last working box and the first non-working one. Possibly a wire's broken in the cable or there's a hidden junction box, but more likely just a bad connection at one end or the other. Once it's narrowed down like this it's easy to redo those two connections (and visually check everything in the two boxes), probably clearing up the problem.