I have a sub panel in my attached garage. It has a small heat pump/air conditioner on it for a bonus room (I believe 50 amp) and a 50 amp welder plug that rarely gets used.
I built a detached garage /shop with a 100 amp panel. Can I run my sub panel in my detached garage to the sub panel in my attached garage?
I have the capability to attach it to the main panel but it would be alot of work and would have to move 2 circuits.
Stryped
It is possible to attach this to a sub panel but you still need to keep the neutral isolated from ground. AND you will have to limit the
100 amp panel to a 50 amp breaker from the 50 amp subpanel. And maybe not even 50 amp since your AHJ may have further limitations on the current loading of your 100 amp panel.Bob AZ
Why would I have to limit it to 50 amps?
Sorry for the confusion, both sub panels are 100 amp.
stryped wrote in news:7fb8939d-a86a-4b09-8852- snipped-for-privacy@j39g2000yqh.googlegroups.com:
Look for a maximum branch circuit breaker size printed on the tag in the panel you intend to feed from. That is the highest you can go. Guessing that you can't go over 70 or 80 amps if you want to feed out of the 100 amp garage panel.
Stryped
It is a code issue. And since your initial message said the first sub panel was 50 amp I quoted 50 amp to the second panel. But with your new sub panel information the limit is 60 amp. Again a code issue. More than likely the 60 amp limit is part of the code limits for branch breakers for the 100 amp sub panel. And your service panel which I presume is 100 amp or more will have this 60 amp limit also. At any rate you can install almost any amperage sub panel but the breaker feeding the subpanel is limited to 60 amps. An additional code requirement is that the continuous load limit imposed by any panel/ load is only 80% of the breaker feeding the branch circuit. The circuit feeding the subpanel from another panel is a branch circuit from the feeding panel. The continuous load limit is usually stated as
3 or 4 hours above or at the 80% point. And more still your subpanel can be above the 60 amp limit to provide additional spaces for additional circuit breakers and the associated branch circuits.Lots to digest but if you are not sure ask your AHJ folks for additional guidance.
Bob AZ
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