House wiring problem

Question for the gurus. I just tested my housewiring (at the wall outlet) and found that I have 120V AC between the hot and return, only I can't tell which of the top two "slots" is hot and which is return. They both show

59.4 VAC with referrence to the third (GND) terminal, on the bottom. Huh? Anyone have any idea what might be going on with my house wiring? It's an old house, built in '49 or '50, and has had numerous pieces added and modified. I was in the attic once, installing the wiring for a bathroom outlet, and got bit by the *white* wire, which should have been my first clue something was wrong. When I asked someone else about that though, was told that it might be normal, depending on what had been put in place. :/

Any ideas or feedback are welcome. Hoping someone can explain this. Also hoping I don't have to rewire my house...

Dave

Reply to
Dave
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Floating ground. It is likely that there is no ground wire at the outlet, and that the origional 2 prong outlet was replaced with a "grounded" outlet, even though there was no ground wire to connect to the ground connection.

Reply to
Bob F

Are you absolutely sure it is 59.4V and not 59.4 millivolts?

Reply to
Jack Hammer

So how do you explain the potential difference between the other 2 wires and ground?

Reply to
Jack Hammer

Hey Bob,

Floating ground... Okay. That would fit with what I saw up in the attic, about the wiring used in the house. sigh At least it's nothing really wierd. Always thought I ought to rewire the house, just didn't want to tackle that project. Wondering if I can live with it... :)

Many thanks.

Dave

Reply to
Dave

Agreed. AND I'd double check with an analog meter to rule out inductive ghost voltages.

Reply to
mike

I did my house bit-by-bit. When I felt energetic, or I had a problem with insufficient circuits, or I was remodeling a bathroom, I rewired the appropriate circuits. The major issues with ungrounded outlets are the lack of a safety ground for grounded equipment, and no ground path for surge protectors, which could help prioritise replacements.

Reply to
Bob F

Phantom voltage. if you tested it with an old analog meter, it would likely show 0V.

easy way to tell, just pull the recep out of the wall, beer of your choice says that it is wired with 2-wire Romex or some other similar wiring method, so that there is no ground present.

At least your PO didn't do what mine did, which was to bootleg all the ground connections to the neutral to fake out the home inspector's little tester gadget. Unfortunately for me, I know in my heart that the people that we bought the house from didn't do this (they weren't that handy) and it was likely the owners before that, so I really didn't have any recourse. Discovered a lot more shady wiring when I went up in the attic to "just replace a few ceiling boxes" to allow the girlie to install ceiling fans. I posted about that here before...

old houses... love 'em (built like masonry outhouses) but hate 'em too (previous owners can do horrible stuff)

nate

Reply to
N8N

....

I once worked for a photographer. He was in his second studio. The original one burned down. Guess who had floating grounds.

Reply to
sligoNoSPAMjoe

Hmm. Okay, so how could floating grounds result in your house burning down. Seriously. Never heard of that.

Dave

Reply to
Dave

Hi, Get an analog meter to make a real reading. If you know the breaker which controls the outlet turn the power off and measure between ground and each lead. I bet neither one shows continuity meaning there is broken ground wire. Another way to look at is to connect a light bulb between either lead and ground. If the voltage is not phantom bulb will glow at half brightness or so.

Reply to
Tony Hwang

You know, something's jogging my memory. I remember now I once tested a different outlet and got the same results, right after we had the house remodeled. And I wonered about it but never persued it. Before the house was remodeled I worked on an outlet to replace the hardware, and it tested normal. In between these two, when the house was remodeled, the contractor (or whoever) had to hardwire their floor sander into the service entrance because we didn't have any 220 VAC outlets, even though we had the normal two "hot" wires (each 110 or 120 but 180 out of phase with each other) coming from the pole. We have central air, and the outside unit (compressor?) is wired for 220 (or 240, whatever, I don't remember) but it is the only thing on the property that is. I am wondering now if they changed something at the service entrance when they hard-wired their floor sander in.

I just filed for a bunch of insurance reimbursements, and we are expecting some extra cash as a result. I need to get an electrician out here to check this out. Anyone have any ideas as to what I might expect to have found? All ears...

Thanks,

Dave

Reply to
Dave

Hi, If you know what GFCI does, then your question is answered. Ground wire is for extra safety.

Reply to
Tony Hwang

Hey Tony,

No idea how a GFCI works, but I understand it shuts off the power really fast upon sensing evidence of a short to ground, or some such. Can you go a little further for me?

Thanks,

Dave

Reply to
Dave

A house of that vintage is very likely to have no ground to the outlets. If you open up the breaker box (fuse box?) and look at the wires coming into the box for the appropriate circuits, you will probably see that each 110V cable entering into the box has 2 wires (black, white) but no associated bare ground wire.

Reply to
Bob F

probably has nothing to do with your problem, there's generally no need to have 240VAC receptacles in your average house unless you have large window A/C units, an electric range, or an electric clothes dryer.

I expect you will find simply a lot of old wiring without an earth ground conductor. Didn't become code until sometime in the 50's or

60's. You can either have an electrician repull everything (and possibly add some receps in strategic locations if you so desire) or else simply install a GFCI recep in the first box on each circuit, your choice.

If you go for the complete rewire route I would also go ahead and get a couple cases of "spec grade" receps and switches and then your house will be all good for the next 30 years or more. Be aware that if you do the full rewire you will also have to install AFCIs on all circuits serving the bedrooms. If you have an obsolete breaker panel that is no longer supported, then you're looking at a panel replacement as well, so you may want to assess that before making a decision.

If you're reasonably handy, this is something you can do yourself (I have, although I still have more work to do.) However it is not something to mess around with, make sure you know exactly how to "do it right" so you don't end up causing more problems than you solve.

nate

Reply to
N8N

OP said house was built in '49 or '50, there wouldn't have *been* any ground unless the wiring was run in pipe or BX.

nate

Reply to
N8N

Sounds like a "floating ground"

Reply to
clare

If done properly, it should be a 2 prong ungrounded receptacle, or a GFCI receptacle, or downstream from (protected by) a GFCI receptacle. If downstream from a GFCI it can be a grounded receptacle even though there is no ground. That could be what you have (but not likely).

Reply to
bud--

It has happened to me on two different occasions. It's also happened to a lot of regulars here.

Maybe you have a really advanced digital meter that isn't affected.

Any time wierd voltages pop up, an analog meter should be used to double check a digital meter.

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Reply to
mike

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