220 Volt Only Sub-panel

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Old 02-24-09, 04:07 PM
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220 Volt Only Sub-panel

I am in the process of installing a small 50 amp sub-panel that will be servicing three 220 volt baseboard heaters. There will be no 110 volt service coming from this panel.

I intend to feed the sub-panel using #6 Romex. There will be no neutral. The bare grounding wire will connect the grounding bus in this panel with the main located in the same building. There is no neutral bus.

Is there any reason why this installation would be unsafe and/or not meet code?

Thanks for any info.
 
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Old 02-24-09, 04:29 PM
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Maybe. Maybe not. What is the wattage of each bb heater? Will the new sub panel be located in, or attached to, the same structure the main service panel is located?
 
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Old 02-24-09, 06:16 PM
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220 Volt Only Sub-panel

Thanks for the reply. I'm confident about all aspects of this install except for the lack of a neutral bus in the sub-panel. All wire and breakers used have been appropriately derated. As indicated in the initial post, both main box and sub-panel are in the same building.

I see no reason why a neutral bus should be installed since I will only use the sub-panel for 220 volt service. However, national code may well require this bus in consideration of the possibility that 110 volt service might be desired in the future by another owner.
 
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Old 02-24-09, 09:14 PM
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The neutral bus is not required. You do need to label the panel 240V-only however.
 
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Old 02-25-09, 06:24 AM
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220 Volt Only Sub-panel

Thank you for that clarification.
 
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Old 02-25-09, 06:41 AM
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Originally Posted by skipslade View Post
However, national code may well require this bus in consideration of the possibility that 110 volt service might be desired in the future by another owner.
This would be the only reason I can think of to pull a neutral. It could come back and bite you in the butt someday.
 
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Old 02-25-09, 07:31 PM
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I see no problem do it this way. In your new sub panel you will need to make sure you mark the grounding wire that it's the ground wire and not a neutral. This will help a new home owner or electrician if he or she ever had to do work in it. If it was myself I would put the neutral wire it. You never know what you may need for a 120 volts down the road.
Jim Beer 4U2
 
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Old 02-27-09, 06:29 AM
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Personally I think this is a bad idea all around. I find it hard to believe that no neutral is required in a panel but ibpooks usually knows his stuff so....

Still a BAD idea. Someone will come along in the future and put a 120v circuit in and tie their neutral onto the ground buss, regardless of labels...

Besides, I always thought a 4 wire setup was mandatory for sub-panels, irregardless of loads served downstream.... Just doesn't sound right to me but do what you will I guess.

I'd atleast make sure that #6 is rated at 125% of the baseboard heater ampacity.
 
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Old 02-27-09, 09:22 AM
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Originally Posted by madpenguin View Post
Still a BAD idea. Someone will come along in the future and put a 120v circuit in and tie their neutral onto the ground buss, regardless of labels...
There's only so much you can do to prevent someone else from doing something stupid. After all, there's nothing to prevent a future owner from replacing the 50A breaker with a 100A, or any of 1000 other unsafe things. In this case, 100' of #6 conductor is a high price to pay for the off chance that someone, sometime might need a 120V circuit and can't get to another panel.

Besides, I always thought a 4 wire setup was mandatory for sub-panels, irregardless of loads served downstream.... Just doesn't sound right to me but do what you will I guess.
It's not that four-wire feeders are required, it's that if you have a neutral it must be separate from the ground. This of course implies a four-wire feeder for 95% of subpanels.
 
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Old 02-27-09, 09:37 AM
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Fair enough. But...

$97 for 100' of 6/2 and $125 for 100' of 6/3 online. I'm sure the price diff is comparable at your local electric house. Someone down the road is going to wish the extra $28 dollars was spent on the neutral.... I can all but guarantee it.

Seems rather sloppy to me but who am I to judge or spend someone else's money....
 
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Old 02-27-09, 11:19 AM
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this would be a single purpose sub

So, I'd think no neutral is the way I would go. Unless, you will have a likelyhood of a 120v thermostat. Then, you are "hosed"....
 
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