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Uncle Skeleton · Apr 17, 2011, 06:25 PM

While replacing my bathroom fan, I discovered that the old fixture was not grounded, and there is no grounding wire to connect to the new fixture. I read that you can sometimes use the conduit as ground, but while the conduit is metal, it doesn't seem to be grounded. The building was built in 1968 as apartments. Since it apparently lasted this long without grounding, it makes me think that going forward without being grounded wouldn't be too big a problem. Would it?

Waragainstsleep · Apr 17, 2011, 06:26 PM

Can't you find a water pipe to ground it on? Just avoid gas lines.

Uncle Skeleton · Apr 17, 2011, 06:53 PM

The fan is in the ceiling. Water pipes are in the walls. It would be a stretch.

Any opinion on going without a ground?

Dork. · 07:15 PM

It's a safety issue, especially for things that have conductive metal cases. If the thing that's plugged in has frayed or broken wiring, then it is possible that the metal case could get connected to the live wire and become energized. These metal cases are normally also connected to the ground pin, so that if there's a problem like this you will essentially have a short circuit which will trip the circuit breaker. But if there is no ground connection, the case will stay energized until you touch it: then you are the short circuit!

If you're not sure that nearby metal is grounded, you may not want to use it, because that could make the whole "energizing random bits of metal in the house" problem worse. You might be better off putting in an outlet with a GFCI switch. Those are typically found in bathrooms, where stupid people might try to dry their hair with a hairdryer in the bathtub. The GFCI monitors the current going into and out of the receptacle, and if it finds a difference because some current is taking an alternate path (like, through you!), it shuts off the outlet fast enough to not kill you. I'm not 100% sure if that solution is up to code where you are, but it's better than what you have.

Edit: It's a ceiling fan, which means that it doesn't plug into a normal receptacle. Can you buy GFCI's in wall switches....?

iMOTOR · Apr 17, 2011, 10:22 PM

Your conduit might be grounded, go to Lowes or Ace and ask for a ground tester.

Originally Posted by Dork.

Can you buy GFCI's in wall switches....?

No, but you could wire it downstream from a GFCI outlet.

subego · Apr 17, 2011, 11:54 PM

I'd say let it ride. There are all kinds of things you plug into a socket which aren't grounded and have metal parts. You'll get zapped if a wire frays at the wrong place on those.

Just be sure to analyze where things could go wrong, so you don't do something obviously stupid. Make sure there's really good strain relief at both ends of the wire. Some judicious use of electrical tape to provide extra insulation at stress points won't hurt.

I'll admit though, I tend to play a little more fast and loose with these things than most people.

subego · Apr 18, 2011, 12:30 AM

Originally Posted by iMOTOR

Your conduit might be grounded, go to Lowes or Ace and ask for a ground tester.

Agreed.

In theory, the wall box with the switch is grounded, and in theory, the conduit is attached to that.

ghporter · Apr 18, 2011, 06:28 AM

If we're talking about a bathroom vent fan, the kind mounted in the ceiling, most are made UNgrounded, mostly because they are "not a risk" because of their location. But grounding one that does have a ground connection is needed. As others have suggested, get that conduit checked out, because it's probably grounded through the whole conduit system. If the conduit is grounded, that means the (metal) box it comes into is grounded too, so it's almost trivial to ground whatever you put in the box.