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I opened up my panel and ran a green wire for ground (14 solid awg) from the grounding bar up through the floor into my office in order to ground an existing outlet. I have also done some grounding where I tapped into an existing grounded outlet in the basement (newer wiring down there) and ran a green wire up to other previously non-grounded outlets.

The only issue I have noticed is on the second senario, and it may be due to the ground coming from one circuit (18) and being tapped into for an outlet on another circuit (6). I find the outlets on both 18 and 6 that have been upgraded to GFCI are tripping every few days.

Is what I have done acceptable? I am in Wisconsin, USA.

  • I don't see any electrical difference in running a separate ground wire. However, for code compliance I'm betting you are supposed to run a 14-2 WG the outlet, which shouldn't be much harder than running a single ground wire. GFCI trips when it senses unequal current flow out and in (i.e. some current flowing through the ground wire, YOU, etc...) It may depend on the devices you have connected to the outlet also. – Ryan Griggs Aug 30 '16 at 3:10
  • Thanks for that, Ryan. This is a pre-1950 house, so it has mostly Knob and Tube wiring on the main and upstairs floors. The newer grounded wiring is mostly in the basement, where it is either new circuits or something easily updated because no one had to go through or tear apart walls. – Will Stensby Aug 30 '16 at 12:36
  • Got it. I understand. I was just assuming if you could get a single green ground to the location, it would be nearly as easy to run a 14-2 to the same location. – Ryan Griggs Aug 30 '16 at 12:54
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What you have done was recently made legal under NEC 2014.

The only hitch is that a 20A circuit requires 12 AWG ground wire. So if the circuits were 20A, they are now 15A.

A ground is nothing but a safety shield. No appliance should be flowing current to ground, not even the GFCI.

You may have already had a ground fault

If a device flows current to ground and the ground is not hooked up, it will "float" the ground to a potentially hazardous voltage, energizing whatever part of your grounding system does exist, e.g. Chassis of equipment, coverplate screws on outlets, etc. However no current will flow unless there's a path back to source.

Suppose you already a GFCI in such a situation? Since no current is flowing, it would not trip a GFCI. This is safe because if you did get shocked, then current would be flowing and the GFCI would trip.

By adding the ground, you created the path back to source, which is assuring that the GFCI trips.

This is laying bare the fact that you have an appliance with a ground fault. You did before, just your lack of ground was concealing it.

Since this is a hot-ground or neutral-ground fault, it is unlikely to be the wiring, which has never been near a ground. I would look hard at appliances.

  • Thanks Harper. When you say 20A circuit, are you saying the circuit at the main panel or the outlet? – Will Stensby Sep 6 '16 at 17:27
  • Okay, I changed the ground source from the GFCI on circuit 18 to a direct line from the panel, and I am still seeing the same issue. First, the GFCI on circuit 18 (refrigerator) will trip, then, approx. 24 hours after that one is reset, the GFCI on circuit 6 (microwave) will trip. The fridge is not that old, and the microwave is newer. I also notice that another GFCI outlet in the kitchen randomly trips, and that only has my rechargeable vacuum hooked up to it. – Will Stensby Sep 19 '16 at 12:43
  • @WillStensby sorry didn't see your earlier commenf. Circuit size is decided by the breaker which is in turn decided by wire. For so many devices to be tripping GFCI's is really weird. Are all these on the same circuit (lose power when the same breaker is turned off)? A ground fault will trip any GFCI upstream of it. Is ther eany place neutral and ground are connected? (besides the main panel of course.)2 – Harper Sep 21 '16 at 1:11
  • Separate circuits. I did remove the GFCI outlet for the fridge and am just using a grounded 3 prong outlet, as I read somewhere it is not necessary to have a fridge on a GFCI, and refrigerators are known to trip GFCI's when going into self defrost mode. – Will Stensby Sep 21 '16 at 13:25

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