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subpanels again? #84913
05/16/03 08:10 AM
05/16/03 08:10 AM
Reel-Break  Offline OP
Joined: Apr 2002
Posts: 178
Can someone clear up the whole subpanel issue?The more I understand the more I`m not sure of.If I add a subpanel to an existing panel attached to home Main or no main required? also if it`s dettached what`s the deal with 6 breakers.I think I have it if it`s detached I may have up to 6 and use main lug if more than 6 must have main right 225.33.Also can I have more than one subpanel from a panel? say a 200 main panel with 2 100 amp subs example one in the garage for work shop in future and one in the basement.I`d like the articals please I`d really like to understand this better.Had a homeowner ask me some questions and I wasn`t sure where to look. Thanks

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Re: subpanels again? #84914
05/16/03 10:18 AM
05/16/03 10:18 AM
resqcapt19  Offline
Joined: Nov 2000
Posts: 2,148
First lets look at the requirement for panels. 408.16(A) requires that a lighting and applinance branch circuit panel "shall be individually protected on the supply side by not more than two main circuit breakers or two sets of fuses having a combined rating not greater than that of the panelboard". Two devices would only be used for a "split bus" panel. There is nothing in this section or any other code section that requires the panel to have a main breaker. The feeder overcurrent protective device is permitted to provide the required panel overcurrent protection. This means that any time you install a subpanel in the same building as the main panel there is no requirement for a main.
When we get to a second building, 225.31, .32 and .33 require building disconnecting means. 225.33 permits you to use up to 6 breakers to provide the required building disconnecting means. So in a sub panel, if you have six or less breakers, no main is required. This assumes that the feeder breaker has a rating equal to or less than the rating of the subpanel. If you need more than 6 branch circuits in the second building, then you must install a main.
There is no code limit on the number of subpanels that can be served from the main panel. You can also feed a second subpanel from the first subpanel.

[This message has been edited by resqcapt19 (edited 05-16-2003).]

Re: subpanels again? #84915
05/16/03 01:10 PM
05/16/03 01:10 PM
Reel-Break  Offline OP
Joined: Apr 2002
Posts: 178
Don thanks for taking the time to clear some of the smoke for me.Seems sometimes I have problem spitting the code out if I don`t have a specific question.Thanks for your time to moderate this forum as well.


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