Home outlet wiring question

arabian knight · #61 01/28/13, 02:20 PM

All this talk about GFI. And if that house is wired like that I bet there is Not One GFI in the whole place. Heck I only have them in my barn, and outside outlets that I PUT IN. But not one is in this house.
Older places never have them. So this talk about GFI's is pretty much mute when looking at the OP situation. I did add one heavier wire and outlet that is on its own. But No GFI. As I do lots of testing of Commercial Coffee equipment. Its 10ga just incase I want to change it over to 220 IF I want to use it on heavier equipment but so I only run the 1800 watt or so coffee machines and without any trouble.

o&itw · #62 01/28/13, 02:46 PM

A GFI breaker has two "op amps" in it. It measures the current going out of the "hot" or black wire and compares it with the current that is coming back though the neutral (white) wire. If there is less current coming back than is going out, that means that there must be some current returning to ground in some other way than the neutral (not good) and it trips the breaker.

Yvonne's hubby · #63 01/28/13, 03:08 PM

Quote:

Originally Posted by idahodave

If the equipment has a short and is connected to ground (like a washer on a concrete floor) the GFI trips. If it's insulated from ground and you touch it and ground at the same time the GFI trips. So yes it does address the hazard of a hot wire shorted to the case.

Thanks... this makes me a bit more comfortable.

Yvonne's hubby · #64 01/28/13, 03:11 PM

Quote:

Originally Posted by o&itw

A GFI breaker has two "op amps" in it. It measures the current going out of the "hot" or black wire and compares it with the current that is coming back though the neutral (white) wire. If there is less current coming back than is going out, that means that there must be some current returning to ground in some other way than the neutral (not good) and it trips the breaker.

Thank you so very much, this is probably the clearest explanation of their (gfi) function I have ever heard.

idahodave · #65 01/28/13, 03:41 PM

Quote:

Originally Posted by arabian knight

Older places never have them. So this talk about GFI's is pretty much mute when looking at the OP situation.

No, it's the easiest way to update outlets in an older home. I think the OP will have a problem finding 2 prong outlets and will have to use GFIs to replace his improperly wired 3 prong outlets.

Sawmill Jim · #66 01/28/13, 03:50 PM

Quote:

Originally Posted by GoldenCityMuse

Obviously, you have not been bold enuff!

Or stupid enough one

Yvonne's hubby · #67 01/28/13, 03:57 PM

Quote:

Originally Posted by idahodave

No, it's the easiest way to update outlets in an older home. I think the OP will have a problem finding 2 prong outlets and will have to use GFIs to replace his improperly wired 3 prong outlets.

With my newly updated education on the function of the gfi, it would make sense to me if the OP were to simply upgrade all of his circuits with gfi breakers at the panel he would be nearly as safe, if not as safe, as he would be by installing all new wiring to have access to the more modern style ground system. Do I have this correct? The reason I am asking this is because I own a couple houses with the "old style" wiring.

idahodave · #68 01/28/13, 04:33 PM

Yes, you can use a breaker panel mounted GFCI if you can find one that fits.

There are some restricitons.

The neutral must not be shared with another circuit. This is because some of the current in the other circuit would travel in both neutrals and cause the GFCI to trip. This could be a problem in EMT (thinwall conduit) where neutrals can be connected together at a junction box. The other commonly found shared neutral is a network where both sides of the line share a common neutral. Sometimes done with split outlets so each side of the outlet is on a different circuit.

Yvonne's hubby · #69 01/28/13, 04:41 PM

Quote:

Originally Posted by idahodave

Yes, you can use a breaker panel mounted GFCI if you can find one that fits.

There are some restricitons.

The neutral must not be shared with another circuit. This is because some of the current in the other circuit would travel in both neutrals and cause the GFCI to trip. This could be a problem in EMT (thinwall conduit) where neutrals can be connected together at a junction box. The other commonly found shared neutral is a network where both sides of the line share a common neutral. Sometimes done with split outlets so each side of the outlet is on a different circuit.

I would be replacing fuse boxes with breaker panels so matching breakers should not be too big a problem. Now sorting out which circuits may be sharing a neutral could be a bit trickier! These houses are old timers and both have had several hands in the wiring over the years. Everything still works, but I was thinking of going through, replacing all the plugs, switches and main panel boxes in order to eliminate basic issues. There is no conduit to deal with, they were both wired with the old two wire cloth covered style romex. and I am pretty sure both have all four circuits... at least thats how many fuses there are in the panels. Complete rewiring would be a tremendous expense that I simply am not capable of at this point.

idahodave · #70 01/28/13, 05:10 PM

I'd pull the fuses and then remove one of the Romex feeders. Use an ohmeter and measure resistance from the white wire on the Romex to the common neutral in the panel. If you have a low (few ohms) reading the neutral is shared. You could then pull the other Romex whites off the common point until the reading goes up.

Don't forget the "No Equipment Ground" label at outlets that aren't grounded.

Yvonne's hubby · #71 01/28/13, 05:19 PM

Quote:

Originally Posted by idahodave

I'd pull the fuses and then remove one of the Romex feeders. Use an ohmeter and measure resistance from the white wire on the Romex to the common neutral in the panel. If you have a low (few ohms) reading the neutral is shared. You could then pull the other Romex whites off the common point until the reading goes up.

Don't forget the "No Equipment Ground" label at outlets that aren't grounded.

Thanks Dave.. You have been very helpful!

arabian knight · #72 01/28/13, 05:53 PM

Quote:

Originally Posted by idahodave

No, it's the easiest way to update outlets in an older home. I think the OP will have a problem finding 2 prong outlets and will have to use GFIs to replace his improperly wired 3 prong outlets.

Yes cause if not that tiny tiny amount that may trickle into the neutral side will TRIP the GFI outlet. They do not take hardly any flow at all. And it trips.