I know how to wire a GFCI receptacle and all the things to go with it in doing so. But what I do not know is the following.

I understand the GFCI receptacle should be first in line to protect the load side going to other standard receptacles, but lets say you have 5 receptacles on a line in a room that has 2 on 1 wall a 1 on each other wall. How or what is the best way to find the first receptacle in line, so the others can be protected. Am I over thinking this? Is there a simple answer? Or do I have to take each outlet off, unwire each to find the firstvin line from the breaker?

Had a couple receptacles go bad, and have decided to replace all of them (30 total in my house and garage). Also want to install GFCIs in the circuits, just want to make sure I get them in line correctly.

  • 2
    If you're just guessing wildly which might be the first, try the one closest to the service panel. Electricians like to save money, so they often try to reduce the amount of cable used. This usually means taking the most direct route.
    – Tester101
    Dec 10 '13 at 2:08
  • If you're replacing them all anyway, disconnecting them to identify the first one isn't really any extra work. Dec 10 '13 at 3:23

There is no magic method. You disconnect an outlet and see which ones are still live, if any. You don't have to disconnect any that went dead when you did one of the others. When they are all dead, you have the most upstream outlet on this circuit in this room. If the circuit feeds multiple rooms, the problem becomes larger, but not different.

Be aware of - keep an eye out for outlets with different circuits top and bottom (generally switched one half for room lamps) they can be tricky to figure out if you don't look for them.

Another approach (NOT my favorite) would be to use GFCI breakers instead. Automatically most upstream, but also more expensive and needs to be for your particular breaker panel, rather than the generic GFCI you can put first in line and replace with another generic GFCI when it fails (they do fail.)


The problem is that each outlet (except maybe the last on the run) will have two cables, one bringing in the power, and the other taking it to another outlet. And, a non-contact voltage tester won't help because they will all show a voltage. So, the only way I know of is to disconnect the wires (just the blacks) on the one that is nearest to the circuit breaker panel, then check for power at the other outlets. If none work, you got lucky, and the power is coming from one of the two cables in the disabled outlet box. You can then test for voltage with a voltmeter, or non-contact tester to identify which one is the power source. If one or more of the other outlets still work, then you'll need to repeat this until you can pin down the power source.

One thing I would do before starting the above is to verify the circuit that each of the outlets is on. Otherwise it could get real confusing.

Also, I wouldn't do it the way you are going to do it. I would get a GFCI breaker instead. I have them in my house, and have never had a problem with one. And, just think, you won't have to spend time tracking down the first outlet in the run.

Good luck.

  • 1
    Breakers are the Right Answer here, yeah. "Combination" breakers are about $50 each, they do AFCI and GFCI, so cover you for all three kinds of arcing: to ground, between wires, and in series along the wire. Not sure they're appropriate for EVERY circuit, though: ask an expert! :D [Oh, and definitely don't install on a circuit that has life support equipment on. Keeping that running is usually considered more important than arc detection!] May 18 at 0:02

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