I am having a weird electrical issue in my living room. There are two circuits for living room receptacles. Receptacles in the west side are in circuit 1 and ones in the east side are in circuit 2.

I bought a used power conditioner and hooked it up to a receptacle in circuit 1. Then after a couple of seconds, the breaker tripped. If I hooked it up to a receptacle in circuit 2, it was OK. I unplugged everything in circuit 1 and hooked up the power conditioner. Same thing --- breaker tripped. So, I don't think it is overload issue. Before I hooked up the power conditioner, I didn't have any issues in receptacles either in circuit 1 or 2. Can any one have an idea where I should look at?


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    What type of breaker is in each of the two circuits? Is one of them a GFCI of AFCI? Commented Oct 20, 2017 at 18:59
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    You unplugged everything on circuit 1 except the power conditioner, but, did anything else in the home get power from circuit 1?
    – noybman
    Commented Oct 20, 2017 at 19:01
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    One other way you can diagnose it is to swap breakers. That would give you na indication if your breaker needs a replacement. Commented Oct 20, 2017 at 19:05
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    Are both breakers the same size (15A, or 20A)?
    – mmathis
    Commented Oct 20, 2017 at 19:11
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    Your breaker that is tripping is a GFCI breaker. I would expect it to trip right away with a GFCI fault. Have you tested circuit 1 with ONLY the power conditioner and nothing plugged in to it? Also, why are you using a power conditioner? GP's? What model is it
    – noybman
    Commented Oct 20, 2017 at 19:43

1 Answer 1


Your power conditioner has a ground fault

But it does not have an arc fault.

That is why it is failing on a combo GFCI-AFCI but not failing on an AFCI only.

The fact that it doesn't trip with the ground-removing cheater proves it is a fault involving the ground wire. That is, it is not a fault to a water pipe, cat, etc.

Now, did the conditioner work with the ground-removing cheater? If its own internal loads now do not work, that means its internal loads are drawing from hot and returning to ground, which you have severed. They should not do that. If the internal loads still work, that doesn't tell us so much.

The fact that the conditioner fails alone on the wire, with only its own tiny load operating, suggests to me that it's a hot-ground fault.

It needs to flow 8ma to trip the GFCI, and the conditioner's own loads should be quite small. It may have a new hot-ground fault due to a short inside the machine, which is separate from its own loads. That could be any value.

Or, it could have a neutral-ground fault due to bad design or a different short. With a neutral-ground fault, power returning to source has 2 choices, and flows down both in proportion to their conductance (1/resistance). Anyway, since current is flowing both paths, one of them correct, it takes more than 8ma to trip the breaker.

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    I suspect that the problem is a design issue with the conditioner -- it could very well have too much capacitance to ground, hence the leakage problems. Commented Oct 20, 2017 at 22:29
  • That and it is used. But a leaky electrolytic should be leaking to the return side, not the ground side, so the fact that it is faulting to ground tells us it is possible that it lies on a design/noise issue. Switch mode supplies can do strange things, then again so can a transformer if there is ringing in the circuit. Just not grasping why it would leak current on the ground vs. neutral. (thus my noise q)
    – noybman
    Commented Oct 21, 2017 at 15:42
  • Possibly they have MOVs or other devices that are bridged between hot and ground or neutral and ground, aiming only to dissipate spikes, and the components have degraded. 8ma x 120V is 1 watt, that coming from a single component, you might be able to see on an infrared thermometer/camera. Commented Oct 21, 2017 at 19:39
  • I think your explanation makes sense and my power conditioner has something wrong inside. Thanks.
    – mikes
    Commented Oct 23, 2017 at 21:47

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