House electrical wiring question

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I'm selling my house and I need to install a few GFCI's before the new buyers move in. House was built in 1964, has Greenfield wiring, and the fusebox was replaced to a breaker box a few years ago. I have wired in new outlets before, installed a few light fixtures and a couple ceiling fans so I'm (somewhat) familiar with wiring. So on to my problem: I pulled out the standard outlet and put in the GFCI (put the wires in the same location) and my circuit tester is showing hot/neutral reversed. What did I do wrong?

 
Last edited:
Wiring-A-GFCI-Outlet.png


?
looks basically right?
 
The one I'm replacing has 4 wires going to it (red and white) and the outlet box is grounded so no ground wire. Either I'm doing something wrong or that spot should not have a GFCI installed there.
 
It's also possible that further upstream someone switched the wires on another outlet. Most houses are wired from the fusebox to the first outlet to the second and on and on in a daisy chain, with relatively few "T"s.

You could either tear apart every outlet in the circuit or hire an electrician. Those circuit tester things are pretty hokey and are marketed for all the wrong reasons. Though I suppose you could run around with the tester to see what else is wrong.
 
I'm just wondering why the standard outlet tested normal and the GFCI tested wrong. I have a couple weeks before I need to get this done (I'll ask a couple of the electrical gurus at work) and if I can't figure it out I'm calling an electrician.
 
Red's a kinda weird color to be primary hot, it's usually the "other hot" in a 3 way or 220 circuit. But I can't speak for 1964 or what they ran in conduit.
 
Your two reds are not the same. One is hot coming in and one is picking up the hot from the other red.

When you install a GFCI, everything downstream is protected by the GFCI. ie. you just need to install one on the first receptacle in your circuit and all the ones downstream are protected.

Switch the red wires in your GFCI and see if that fixes your problem.
 
Originally Posted By: Leo99

Switch the red wires in your GFCI and see if that fixes your problem.


So just switch the two red wires on the same side or swap sides?
 
Originally Posted By: road_rascal
Originally Posted By: Leo99

Switch the red wires in your GFCI and see if that fixes your problem.


So just switch the two red wires on the same side or swap sides?


SAME side. Don't swap sides. The GFCI wants the hot wire on one specific screw and the continuing red on the other screw. You should swap the white wires, too.
 
see my earlier pic
basically
line terminal
load terminal

the load terminals are to transfer gfi protection to downstream outlets
 
Originally Posted By: eljefino
Red's a kinda weird color to be primary hot, it's usually the "other hot" in a 3 way or 220 circuit. But I can't speak for 1964 or what they ran in conduit.


Is it just me or is there a black wire in there?

Red would then be used if there is a multi wire branch circuit... Still doesn't explain reverse polarity I suppose...
 
Go back to square one. Disconnect all 4 wires and get a tester that beeps on a hot wire. The wire that beeps is the hot wire, probably one of the red ones. That one should go to line. The other one that isn't hot would go to load. It's normally black, but if someone used 12/3, you'd have a black wire and a red wire in addition to the white wire. Who knows what's going on though, maybe someone converted a 3 way switch into an outlet.
 
This!

You need to find out which is hot and which is going to a "downstream" outlet.

Originally Posted By: Wolf359
Go back to square one. Disconnect all 4 wires and get a tester that beeps on a hot wire. The wire that beeps is the hot wire, probably one of the red ones. That one should go to line. The other one that isn't hot would go to load. It's normally black, but if someone used 12/3, you'd have a black wire and a red wire in addition to the white wire. Who knows what's going on though, maybe someone converted a 3 way switch into an outlet.
 
Got a volt meter?

Disconnect all of the leads and compare each one with the ground (the box in your case). You will figure out which is the hot wire and put that one where it belongs (marked "line" on your GFCI).
 
Also note that most GFIs have at least seven screws on the back,

Hot-in, Neutral in
Hot-pass-through, neutral pass-thru
protected hot pass-thru, neutral ditto
ground

If you're wiring a bathroom you'd typically use the protected pass through and put the little "hey I'm protected" stickers on downstream outlets. But sometimes (often?) you want to only protect *that* outlet so you don't knock unrelated rooms into darkness.

The new ones I've seen have a sticker you have to pull off to expose the last pair of screws.

All this doesn't to me explain the alleged reversed polarity.
 
Thanks for the guys. I'll deal with it on Tuesday (no time this weekend). I was looking at other outlets and I think I know what the problem is (house is a mess of white, red and black wires). I have the proper tools (voltage meter/ sniffer/ tester/ etc) I have left over when I did some wiring in an old townhouse 20+ years ago. Thanks again. I'll post the results.
 
Disconnect the wires and figure out which is hot coming in with a meter. That needs to go to the proper terminal on the GFI.

Keep in mind some codes now want a arc-fault circuit breaker if you open up a circuit to add outlets.
 
Also be aware of bootleg/faulty grounds, and the idea that very old flexible metal jacket (Greenfield) may not provide adequate ground, both of which might cause one to read a 3 light tester incorrectly and/or provide a false positive. Sometimes a white wire can be hot, but it is supposed to be marked with black tape or paint.

However, I think that you answered your own problem....a mess of white, black, and red wires. It will be interesting to find out why the regular receptacle tested o.k. and the GFCI didn't.
 
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