ECN Forum Forums General Topics of the Trade General Discussion Area 100 AMP Sub from 150 MAIN

Is there any code against running a 100 AMP Sub Panel off of a 150 AMP Main Breaker Panel? Its a residential application the person who initially tlooked at the job mistook it for a 200 AMP Main and bid for a 100 AMP Sub. Just trying to save the checkbook to avoids eating a 200 AMP upgrade...

Any help?

Sure, you could connect a 200 amp rated subpanel onto a 100 amp service panel if you wanted to.

There is only one issue to consider and that is the total calculated load or the real demand load for the past year.

So if either the calculated load or the demand load is under 150 amps you are good to go.

I don't believe there would be a problem as long as you size your conductors accordingly. I'm assumming that your 100 amp panel is a main lug only. If this were the case then your protection and means of disconnection is back at your 150amp panel. I would check with your local inspector, it may fall into an issue on that level.

Best of luck!!!

You could have a 100 amp sub off of a 100 amp sub off a 100 amp sub off a 100 amp sub off a 150 amp main. In other words your OK most likely.

Right on. Then 100 AMP Sub'd we be.

Thanks guys.