wire size

[vettmanjj]

I have a 2-wire, 240V circuit that originally served my electric hot water heater. I'm converting this to a 3-wire 240V circuit that will feed 6, 2-gang duplex outlets. Protection for this circuit is a 2-pole 25 amp breaker (thin type). Circuit is wired with 10 gauge, but I want to use 12 gauge. Is it okay to re-wire with 12 gauge? I know 30 amp needs 10 gauge, but was wondering if 12 would be okay for 25 amps. I think I know the answer, i.e., if I switch to 12 gauge, then I'll have to change the breaker to 2-pole 20 amp.

Thanks

 

[Hud]

#12 is only good for 20 amps. I would leave the #10 if it is close to where you want to go, then use #12 from there to other receptacles and put all of it on a 20 amp breaker.

 

[vettmanjj]

The 10 gauge is 2 wire with ground but no common since it only fed the hot water heater 240v. Guess I'll just have to pull a 12 gauge from the panel, and put in the 2-pole 20 amp breaker. What makes this all the more annoying is that I have a 30 year-old Zinsco/Sylvania panel (2, 200amp panels), and only used breakers are now available. I don't care what others say about a Zinsco panel, but I have never had a problem with mine. Knock wood, but I've never had a breaker go bad on me. Thanks for responding.

 

[mrb]

is this in conduit or is it romex?

 

[vettmanjj]

Romex

 

[mrb]

Romex

then you cant simply add a neutral. you have to run a new cable. All conductors of a circuit must be contained within the same cable or conduit.

edit: nevermind. on first read i got the impression you were going to add a third wire to the existing installation.

Is this in a garage or somewhere else GFCI protection is required? That will affect how you want to run your circuit.

re: zinsco -you wont find out you have a bad breaker until you have a fault and the breaker wont trip...

 

[vettmanjj]

Yep, that's what I thought. Now can you help me decide if I need a breaker where both sides trip at the same time or individually. This circuit will have one 240V outlet for my air compressor, and the rest will be 120V (separate feeds to each outlet in a 2 gang box). I'm thinking I need a breaker where each side trips individually. I know that on a strictly 240V circuit, you want a breaker where both sides trip together. In my case, I'm not sure.

 

[mrb]

is the compressor portable or fixed in place?

 

[fefarms]

zinsco breakers are noted for not tripping when they should. Sure, you've never had a problem, but it's like an insurance company that doesn't pay when you have a claim.
You need a two pole breaker with a handle tie, not separate breakers. It will still support the same total load, but it is much safer to open both legs if there is a fault in either -- plus the handle tie helps ensure safety when you "flip the breaker" to work on the circuit.

 

[vettmanjj]

Thanks, now I know which breaker to order--it's a zinsco R-38C, 2pole, 20 amp. This has been my first time at this forum; I'm very impressed with the knowledge and quick response of those who have answered my questions.

 

[Aceman]

The Home Depot here sells a Zinsco style breaker rebadged as Connecticut Electric. I've never bought one, but they look just like a Zinsco. I'm not sure if they're new or remanufactured.

 

[thrifty bill]

Assuming your compressor is not portable, I would run a separate circuit for that, then a regular 12/2 110 circuit for your outlets.

 

[vettmanjj]

I know ubiz makes a "zinsco-style" breaker; Johnstone and Grainger sell them, but very expensive. I'm planning to go with a used one that's guaranteed for a year, and has been tested.

 

[nehog]

Yep, that's what I thought. Now can you help me decide if I need a breaker where both sides trip at the same time or individually. This circuit will have one 240V outlet for my air compressor, ...

Since this is a 240 volt circuit, the handles have to be ganged. No other option there.

As well, I'm not comfortable with ganging more 120 volt outlets off the 240 volt compressor outlet, for a lot of reasons (I'm not sure if code even allows this).

Since you need to pull new wire anyway, why not just do it 'right' and pull one dedicated circuit for the compressor and another for the 120 volt outlets?

 

[vettmanjj]

I'll just leave the 240 circuit intact, and pull a new one for the 120 outlets. Thanks for the advice.