Hi,
I have a 30 amp subpanel fed by a 10/3 wire.
My electrician told me that the code stipulates that the panel contain no more than 4 circuits.
Why such a limitation? Why can't I split 30 amps among 40 circuits if I want to? Doesn't the 30amp breaker protect against overloading?
Thanks!
Aaron
I would question what section of code he's making reference to
Probably the part that says everything must be installed in accordance with its listing -- and the panel is listed, and labelled, for only four circuits.
I can buy a panel that says 100amp (meaning < 100amps) and has 20 circuits.
As Doug points out, if the panel is listed for 4 circuits max, you wouldn't be able to exceed that. Yes, you can buy a 20 circuit panel with 100 amp buss, and even if they'll fit, you aren't allowed to install more than 20 circuits in it
The box will say how many circuits it can have. You can't go over that. Take a walk down the lowes aisle with breaker boxes. They all have a limit.
OK, I think I confused everyone. My contractor tells me that I'm not allowed to install a panel that can take more than 4 circuits. And I'm wondering what the rationale is for that particular limitation.
It is not a bad design decision but I am not aware of a code limitation in a dwelling. In commercial you are limited to 180va per receptacle. The limitation on a panellboard is the number of overcurrent devices, not the number of circuits. Some breakers will take 2 circuits per terminal..
One of several possibilities: you misunderstood the contractor; the contractor misunderstands, or misstated, the rule; or there is some *local* rule limiting the number of circuits in a subpanel. There is no such limit in the National Electrical Code; the only limit under the NEC is the number of circuits that the panel is identified for.
But I think there are some rules related to the total of the amperage of all the breakers in the box as it relates to the 30 amp feed, isn't there? I know you can't just infinitely add breakers to a 30 amp circuit.
There is also the rule about how many motions it taks to cut off all the power but I thought that was 6 or 8, not 4? Unless there is a local code that says 4 is the max. OP - this rule limits how many breakers you can have in a box without putting a "main" breaker in the box as well.
OK, it sounds like he is telling you that you can't feed a six circuit panel with a 30 amp feeder, in which case, he would be mistaken. Depending upon what you intended to feed with the panel, it may not be practical, and you certainly don't want to overload the feeder and cause it's main to trip.
*I'd like to know all of the facts. What were you planning to feed out of this 30 amp sub-panel?
That's not the OP's question. His electrician, I think< is saying regardless WHAT panel he uses, if he feers it with a 10/3 protected at
30 amps he cannot put more than 4 circuits in - even IF he instala a 100 amp 20 circuit sub-panel.
related article will shed some perspective on this, this i just found at:
Sometimes a separate circuit is recommended for various reasons. House fan, freezer, hot tub, theater room, water heater, lighting, etc. Never heard of a 4-circuit limitation, sounds rather "limited," but my guess is the 10# wire and its length to main.
I agree with others that there is no limit. As gfretwell posted, for commercial a receptacle counts 180VA which eventually gives you a limit. Someone wire every receptacle in their house on a separate circuit - a very large number of circuits.
A *service* can have up to 6 disconnects. (Actually there are additional disconnects that do not count.)
Generally a panel has to have source overcurrent protection equal to or less than the panel rating. A subpanel is normally protected at the source of the feeder to the subpanel. In general you don't need an additional main breaker in a subpanel.
What disconnects do not count towards the 6 limit?
From 230.71(A)
For the purpose of this section, disconnecting means installed as part of listed equipment and used solely for the following shall not be considered a service disconnecting means: (1) Power monitoring equipment (2) Surge-protective device(s) (3) Control circuit of the ground-fault protection system (4) Power-operable service disconnecting means
Also bear in mind there WAS an additional requirement that a "lighting and appliance panelboard" (one mostly feeding branch circuits) have a maximum of 2 disconnects and that WAS usually the practical limit for most applications like that sub panel in your detached garage.. The 2008 code eliminated the classifications of panelboards and I suppose that means a remote 6 breaker panel would comply with the 6 switch rule now. It is a question that will probably get bounced around building departments so you better ask the AHJ
As I read the code, the 2 disconnect exception (408.36) allows a split bus panel. It can even be a subpanel. Do you have any idea why that is still in the code? What do you use the 2nd disconnect for?
I imagine you are right about the split bus panel. Things languish in the code until someone changes them.
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