Two prong outlets and GFCI's

How do you all write up two prong outlets and GFCI’s that don’t trip, due to two prong replaced with GFCI. I relaize this is ok, however a woman today was very concearned with the all the two prong outlets. I expained that the panel was updated on this 60yr old house 8yrs ago and everything else looked ok. Maybe it just wasn’t my day, but how do you expalin???

Thanks in advance…


A GFCI will work without a ground wire. However, you can’t test it with a tester without a ground wire. You can only use the self test button for testing.


If I understand you question - 2 prong replaced with a GFCI – it will trip as designed - no problem if not it has a problem

Here is what I would explain to your client - When the house was built it was constructed as per the rules of the day. Times change but that does not mean that the old way are not acceptable. The rules are that it can remain as built as long as no major changed are made. If major changes are made then everything has to be brought up to date

You have checked everything out and have found no problems that you have not documented. Thus no problem

BTW - at some time the house might have been rewired with 2 conductor with a ground. With two prong sockets the ground would have been connected to the metal box. Thus a 3 prong socket could be installed and wired properly – Just a thought that is beyond the scope of an HI



Thanks Ron… I do test the manual trip on GFCI’s to see if they are wired correctly. If they don’t re-set then they are not, however your right the tester will usually show a reverse polarity if it’s a old two prong without a ground and will not trip. This still is safe, but do you still write it up???



It can be tested IF you supply a ground for your tester

Sometimes the metal box or a wire to another ground like a METAL water pipe

In practice it take too much time to do the test. I mark it down as tested with the test button.


While we’re on the subject, I had a grounded GFCI the other day that tripped with the test button, but not with the tester. The tester tripped every other one in the house except that one. ???

Without going into the why which is beyond the scop of the HI

Just note it in your report

As a matter of note – see the below – the ground not conected which your tester should have caught



Most likely, it was not truely grounded. What type of tester were you using?

Actually the best way to check a GFCI receptacle is to use the built-in test/reset buttons (with your plug-in tester inserted while you check it).

Pushing the button on your plug-in tester doesn’t completely check things out on a GFCI receptacle, and usually puts a load on the ground wire (which may not be good under the wrong circumstances).

Also note that older GFCI receptacle may not have the lock-out feature on incorrect reset (partly why ya keep your tester plugged in during the check).

JMO & 2-nickels … :wink: