30 A circuit

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  #1  
Old 10-01-05, 04:51 PM
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Question 30 A circuit or subpanel?

Hi all,

In my garage remodel, I may run a 30 A, 120 V circuit for two 1500 W heaters. Here's what I plan to do:

1. Install a single pole 30 A breaker.
2. Run 10 AWG to the garage and connect it in the breaker panel, black to the 30 A breaker, white to the neutral, copper to the grounding bar.
3. Control the heaters with 20 A switches.
4. Use 20 A receptacles to plug the heaters into.

Is this okay? Does the wire have to be in conduit?

I figured that the draw on each heater will only be 12.5 A, so I should be good if they're run in parallel.

Would it be easier to just put in a double-pole 40 A/240 V breaker to feed to a subpanel in the garage? The garage circuits would total 70 A all at 120 V... If so, would I use 6 or 8 AWG from the breaker box to the subpanel?

Sorry for so many questions, but I want to choose the best option and get it right. Thanks for the feedback, folks!
 

Last edited by Gizzorge; 10-01-05 at 05:43 PM.
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  #2  
Old 10-01-05, 06:54 PM
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You plan has many holes. You cannot put 20-amp receptacles on a 30-amp circuit. You cannot plug these heaters into a 30-amp circuit anyway. Those are all code violations.

This isn't a code issue, but a recommendation. Use 240-volt heaters.

Whether or not you need or want a subpanel depends on many factors. Is the garage attached or detached? Do you need more circuits in the garage? What besides the heaters do you want to run in the garage? How much power do you need in the garage?

You can't possibly begin to discuss wire or breaker size until you can answer the above questions.
 
  #3  
Old 10-01-05, 07:09 PM
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Smile Subpanel

Yes, after stopping to think about it, I see why it would be a problem. 20 A receptacles on a 30 A circuit... Looks like that won't work.

In the attached garage, I have the lights, and plan to use the usual electric power tools: saw, drill, etc. No big ones like welders. The heaters I want to use only come in 120 V models. They are perfect for my use and are low-cost. Similar quartz radiant heaters that do use 240V are well over $150.

The problem I have is that my main breaker box is pretty much full with 30 breakers (that's all it holds), which will leave me with little or no room to expand after my little garage project. That's where the idea of a subpanel came from.

On the garage subpanel, I'd have a 20 A circuit for lights and a few outlets for a couple traffic signals, a 20 A breaker for the other receptacles in the garage and outside the house, and then 2 20 A breakers, one for each heater.

Even if I get a pro, I still would like to be familiar with what wire I'd expect and a breaker size to feed the subpanel. I'm a first-time homeowner, and i want to be educated so the job gets done right by the person I may hire.
 

Last edited by Gizzorge; 10-01-05 at 07:27 PM. Reason: Typos
  #4  
Old 10-02-05, 07:15 AM
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It is interesting to hear that you existing panel is loaded with 30A breakers. What serves your receptacles and lights in the house? They cannot be served by anything bigger than 20's.
Sounds like a subpanel may be your solution. I'd put it near the main panel and serve any large loads (1500W heaters), from the main panel, so as not to struggle with voltage drop issues in everything from the sub.

edited:After re-reading I think you said (30) breakers, not 30A. Never mind!
 
  #5  
Old 10-02-05, 11:39 AM
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I suggest #6 copper Feeder Conductors, protected by a 2-pole 60 amp C-B, to supply the S-P.

Stuctural conditions would determine the choice of Wiring Method--- Non-metallic cable, EMT, PVC conduit---- EMT & PVC are the most likely choices if the wiring is routed along and across walls & ceilings covered by sheetrock.

Good Luck , & Learn & Enjoy from the Experience!!!!!!!!!
 
  #6  
Old 10-02-05, 05:23 PM
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Question Subpanel!

Well, after talking with an electrician today, I've decided to put in a subpanel. It will have a 60 A double-pole breaker in the main box, and 6/2 NM through the wall (all of maybe 10 feet - if that) to the attached garage subpanel.

Although something struck me as weird. The neutral buss in the subpanel should connect with the neutral from the feed, right? He was telling me that the neutral and ground are bonded together at the subpanel, so I only need 6/2 and not 6/3. Is that right? I guess that they are joined at the main panel and all, but it didn't make sense for a sub.

Thanks.
 
  #7  
Old 10-02-05, 05:44 PM
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You need 6/3. The neutral and ground may not be bonded together in this subpanel.
 
  #8  
Old 10-02-05, 06:34 PM
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You need a new electrician. If your electrician really told you that you only need 6/2 then he isn;t the right person for your job, or any job until he learns his trade.
 
  #9  
Old 10-03-05, 01:36 AM
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That's what I thought. Thanks!
 
  #10  
Old 10-03-05, 08:49 AM
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Please know that a "6/3" Non-metallic cable is comprised of 3 #6 insulated conductors, and a bare Equiptment Grounding Conductor.

Good Luck ,& Learn & Enjoy from the Experience!!!!!!!
 
  #11  
Old 10-08-05, 06:47 PM
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Question

Will I need to use conduit if I am using 6/3 NM cable? Like I stated above, it is only going a max of ten feet: up from the breaker panel into the attic (or crawlspace... not sure yet) through the brick wall, and down into the attached garage.

Thanks.
 
  #12  
Old 10-09-05, 10:16 AM
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Generally not for NM cable.
 
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