220v question... (window, vac, installation, master bedroom) - House -remodeling, decorating, construction, energy use, kitchen, bathroom, bedroom, building, rooms - City-Data Forum

jimboburnsy · 07-20-2009, 09:31 AM

Alright,

I have an old 220v outlet in my master bedroom (ran a window A/C unit in a former life) that I've been meaning to get around to for quite some time.

This is old, 8 guage stranded copper, ungrounded romex hooked up to a 40 amp tandem breaker.

I would like to remove the old tandem breaker, replace it with a pair of 15 amp breakers and install a 2-gang box with GFI (marked "no equipment ground", of course) in place of the old 220v outlet (this circuit was dedicated to the window unit, probably a retrofit).

I will be able to power each outlet with one leg of the 220v, but I will only have a single neutral. Is it possible for me to create a dangerous condition by having two outlets powered by separate circuits on a common neutral?

My other possibility (or maybe 'another' possibility) would be to simply cap one of the hot legs and piggyback both outlets, leaving an unused slot at the panel.

What's better?

Bydand · 07-20-2009, 10:36 AM

Sharing a neutral won't work with two GFCI's usually. And the breaker would have to be a 2 pole breaker to break both sides of the circuit at the same time.

jimboburnsy · 07-20-2009, 10:51 AM

Quote:

Originally Posted by Bydand

Sharing a neutral won't work with two GFCI's usually. And the breaker would have to be a 2 pole breaker to break both sides of the circuit at the same time.

Good point about the GFI's, I hadn't considered that...

About the breaker, why would it be necessary to have both sides of the circuit broken at the same time if the hot legs are split into separate circuits?

Cosmic · 07-20-2009, 12:22 PM

You really want to use the old 220VAC wires to install two normal 115 VAC receptacles.

If so I would just disconnect it all in the panel. Do a standard three wire grounded installation using those wires. It could be ganged in the bedroom for as many outlets as you wish. The wire size is way over kill for any normal 115 VAC circuit. One of the receptacles in the bedroom (first one) could be a GFI, the others downstream protected by it.

Could even make the one circuit a 30 amp, put the right size breaker in the panel, have a spare slot. Just get all the parts sized / rated right for the circuit. Wire size sure will handle any load.

jimboburnsy · 07-20-2009, 01:25 PM

Quote:

Originally Posted by Cosmic

You really want to use the old 220VAC wires to install two normal 115 VAC receptacles.

If so I would just disconnect it all in the panel. Do a standard three wire grounded installation using those wires. It could be ganged in the bedroom for as many outlets as you wish. The wire size is way over kill for any normal 115 VAC circuit. One of the receptacles in the bedroom (first one) could be a GFI, the others downstream protected by it.

Could even make the one circuit a 30 amp, put the right size breaker in the panel, have a spare slot. Just get all the parts sized / rated right for the circuit. Wire size sure will handle any load.

Understanding check - You're saying I should re-purpose one of the wires as a ground? If so, I'm embarrassed that I didn't think of that.

Solves several problems.

In case I have an electrician poking around in there in the future, is marking the wire as "ground" with tape or a tag sufficient for the code? Also, If I don't have enough slack to get to the main grounding terminal, can I use a 12 guage jumper with wire nuts?

Cosmic · 07-20-2009, 01:45 PM

For the wire to be used as a ground just strip the insulation, it will be bare like all other ground wire. No real way to confuse what happened.

If you want just a 20 amp circuit, a #12 wire jumper to get to the ground bus should work, provided you put in a 20 amp breaker, same as any other 20 amp circuit.

I suppose you can use wire nuts in the panel. I don't like them. I might wrap the bigger wire with the #12 and solder it. Lots of places are quite anal about the subject of splices and where they occur / how it is done.

But everything considered should work for you.

jimboburnsy · 07-20-2009, 02:56 PM

Quote:

Originally Posted by Cosmic

For the wire to be used as a ground just strip the insulation, it will be bare like all other ground wire. No real way to confuse what happened.

If you want just a 20 amp circuit, a #12 wire jumper to get to the ground bus should work, provided you put in a 20 amp breaker, same as any other 20 amp circuit.

I suppose you can use wire nuts in the panel. I don't like them. I might wrap the bigger wire with the #12 and solder it. Lots of places are quite anal about the subject of splices and where they occur / how it is done.

But everything considered should work for you.

But if I wanted to go with a 30 amp breaker I would need #10?

If I solder it would I need a crimp or something to that effect?

Cosmic · 07-20-2009, 03:39 PM

Yeah you would go to #10 for that section of splice wire to go up to 30 amps.

You probably could do a crimp connector if you had one that big.

For the solder you normally just do a full wrap a bunch of times all way round and then maybe a bit of spiral out to the end.

jimboburnsy · 07-20-2009, 03:53 PM

Quote:

Originally Posted by Cosmic

Yeah you would go to #10 for that section of splice wire to go up to 30 amps.

You probably could do a crimp connector if you had one that big.

For the solder you normally just do a full wrap a bunch of times all way round and then maybe a bit of spiral out to the end.

Cool.

southgeorgia · 07-21-2009, 10:47 PM

shared neutral works fine w/ two GFCI receps; you're working on the line side.

If you want GFCI protection at the panelboard, use a 2-pole GFCI.

Do not install a 30A circuit breaker unless you plan on using a 30A receptacle, which you cannot plug a standard 120V plug into.

You want to disconnect both lines simultaneously to protect you or someone else from inadvertently disconnecting the neutral at the buss w/ one line still hot.