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zxcvbob zxcvbob is offline
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Default house wired without separate ground - problem?

Nate Nagel wrote:
Bob F wrote:
"Nate Nagel" wrote in message
...

All right, I'm feeling mildly dumb and a little sheepish not to mention
slightly sick here... just bought a house for the first time less than
a month ago, and knew that it had some minor wiring "issues" but now
that I'm assessing what I have it appears that there are bigger issues
than previously anticipated. Anyway, here's the deal. House is a two
story colonial with full basement, built late 1940's.
It appears that throughout the house wherever the wiring was
hidden behind plaster it was run in NM not BX and there is no grounding,
period.



It's also possible that the wiring could be knob-and-tube in a house of
that age.

Bob


No, it's definitely some early type of NM, although it may not be
officially designated as such. There's two plastic-insulated conductors
(that must be a pretty early use of same; as far as automotive stuff
goes I believe the transition was made about 1955 - at least it was for
Studebaker; I have a '55 coupe which (fortunately) has plastic
insulation on the wiring) in what appears to be a tar-impregnated cloth
jacket. But no ground.

I really, REALLY don't want to have to rewire two complete circuits,
although at this point it kind of looks like I'm going to have to. I
might even have to involve a *gasp* electrician due to the magnitude of
what this project looks like it's shaping up to be, which makes my
Y-chromosome cower in shame. I suppose I could just install new
non-grounded receptacles ahd that would be technically correct, although
then I'm back where I started, as there's computer equipment on the
second floor, and a UPS theoretically should have a ground... also
would feel better if the stuff in the bathroom were grounded (although I
was thinking of rewiring the bathroom anyway to meet current code with a
dedicated circuit, GFCI, etc. which is somewhat doable as there's a
small chase going down to the basement behind the bathtub, and an access
panel, so it's "just" a matter of getting a cable from behind the
bathtub up into the attic and then back down to the light switch...)

I suppose it's not acceptable to cheat and ground stuff to the nearest
water pipe...

nate




You can still buy ungrounded receptacles and put things back like
original. Most circuits don't really need a ground, like the upstairs
bedroom convenience outlets.

Where you really need grounds (bathroom, kitchen counters near the sink,
your computer UPS, etc,) you can run a separate green wire back to the
service panel ground (or to the nearest grounding electrode conductor,
if that is easier.) The ground wire does not have to run with the
current-carrying wires if you are updating old work.

You can also install a GFCI breaker and then use 3-wire receptacles,
leaving the ground terminal disconnected. In this case, you technically
need to put a sticker that says "GFCI Protected. No Equipment Ground."
on each of the grounding outlets that has a floating ground.

You can also protect circuits by wiring them thru the LOAD terminals of
a GFCI receptacle.

The most practical solution will probably end up being a mixture of
these methods. HTH :-)

Bob