I'm remodeling a room and sorting up a rat's nest of questionable electrical practices... boxes hiding in the wall, wall fixtures being used to branch circuits, etc.

At this point, all of the hard stuff is done, and I'm puzzled by what I thought was the simplest part of the job -- replacing a cracked wall outlet. After testing everything and turning the power on, the surge suppressor attached to the outlet indicates a wiring fault.

Here's what I've done so far:

  • Triple-checked the connection to the socket and ground.
  • Verified that the circuit is properly grounded.
  • Checked other outlets terminating in the same place.
  • Tested the outlet with a testing device (checks clean)

Any ideas where to go with this? I'm thinking:

  • Bad surge suppressor?
  • Defective outlet?
  • Damage to cable in the wall?
  • 1
    So all of your testing equipment says that the outlet is fine but the surge suppressor indicates that it is not? Does your testing equipment work on intentionally bad wiring? Does your surge strip trip on known good wiring?
    – Ryan
    May 21, 2012 at 1:59
  • What type of tester did you use to determine it's ok? ("Tested the outlet with a testing device (checks clean)")
    – Steven
    May 21, 2012 at 2:48
  • @Steven I used a simple receptacle tester. en.wikipedia.org/wiki/Receptacle_tester May 21, 2012 at 12:59
  • 1
    These devices tend not to do well with testing grounding isues; in particular, they can't usually tell if there was a ground/neutral swap. The surge supressor might be a better test of this as it does more then just test continuity.
    – Steven
    May 21, 2012 at 14:01
  • 1
    You might have earth touching neutral somewhere. possibly a screw that nicked into neutral? I had that happen many times by mistake with Earth leakage, keep on tripping. Had to go and take out all the plugs from scratch- check if it tripped, then one by one put it back while checking if it tripped the earth leakage. Might be the same in your case.
    – Piotr Kula
    Sep 20, 2012 at 12:48

1 Answer 1


get a cheep volt meter and see if ground to neutral is 0 ground to hot is 115-120 and if hot to neutral is 115-120 if ground does not match neutral or there is voltage between ground and neutral there is a problem. I have a outlet that gets 50v between neutral and ground but the other 2 are normal. the electrician who put that in there some how managed to also flip the hot and neutral in the walls so that both breaker side and wall side look like they are wired properly but are reversed. a cheep volt meter is 15-40$. the battery units are pretty decent at telling you there is some kind of problem but not what it is. duno about surge bars though.

  • I don't really see how this answers the question, I think this answer would be more appropriate as a comment
    – Steven
    Sep 19, 2012 at 23:39
  • 1
    his testers give no verifiable data on if it is good or not. the only proper way to get an answer to what hes talking about is to get meter readings. if the meter reads that all 3 test points are exactly as they should be then the outlet is good ergo the surge supresser is reading faulty. if the readings fluctuate or are not as they should be you can test the wires at the wall if they also are wrong/fluctuate then its in the wall/pannel. if its just cross wired after shutting the power off to the outlet you can correct the wiring direction.
    – Kendrick
    Sep 21, 2012 at 0:55
  • 1
    I fail to see how that is not an answer to his question fluctuating grounds are a pain to find when its in the wall. as many runs span multiple rooms and you have to spend a bit of time to trace all the outlets attached to that 1 run by turning it off and seeing what stoped working. then start with the closest outlet on the line and verifying it tests as expected and move away from the source till you find an outlet that is not working right. pull the power and check the last working and first broken outlet to verify its not misswired some how.
    – Kendrick
    Sep 21, 2012 at 1:08
  • You've provided some good tips in your comments - can I suggest editing them into the answer?
    – Steven
    Sep 22, 2012 at 14:37
  • Yup. When two things disagree, find a third. That doesn't mean the two that agree are correct but it's a start. It's possible that the suppressor is detecting an over- or under-voltage condition and the meter will indicate that while the outlet-tester will not. Oct 12, 2012 at 20:45

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