Do accessory buildings on residential property require a main breaker when a subpanel is installed? If you could give me the code reference it would be helpful. I'm looking but have not found it yet. Thanks. Steve..
225.31 requires a disconnect and 225.33 says that can be up to 6 switches or breakers. If you have a panel with a max of 6 breakers, that can be your disconnect without a main. You could also have a line side disconnect switch in the feeder in or on the building.
Greg, what if I have less than 6 breakers in the subpanel, but it has spaces for more, and may HAVE more in the future. Will I be required a main breaker or is this not identified in the Code? Also why can you buy 40 circuit main lug panels if a main is required after 6 breakers. I guess I'm a little confused on the code references on this one. Thanks again
This has always been an issue that concerned me. The code really just applies to the installation as presented to the inspector, not what happens when they hear you slam the door on your truck and drive away.
I actually wrote a proposal to require wire to be sized to the largest fuse that would fit in a disconnect, just to see what they said. The answer is basically, you go on what is there, not what an unqualified person might do later.
The example was 400a switch gear with a set of 225a fuses in it and a 4/0 feeder. There were well over a dozen empty breaker slots in the load side panels and we were turning this over to state "maintenance men".
Greg, forgive my dullness of head at this point. I'm trying to figure a price on a job and the "head work" is getting a little weary:) What I'm wanting to do is come out of an existing 200 amp service panel that is mounted on the outside of the house, and run #2 cable to a subpanel that is located in a utility bldg. that is approximately 25ft. away from the house. I want to mount a 12/24 main lug panel in this bldg. if allowable, then feed back out of this panel with #4 cable to another utility bldg. that is about 60 ft. away from this bldg. and set a small 8/16 circuit main lug panel. Of course the panels will have main breakers ahead of the "feeders". I would call the local AHJ but I've called them recently about another question, and I don't want to "wear out my welcome":) I've got to make a definite decision so I can figure the right kind of panel in the price. Thanks again for the reply. Steve...
sparkyinak, my question is not which is the best to do at this point. I agree that the main breaker is better, but in this situation, the bldg. is only about 10x10 and does not warrant a panel big enough with a main breaker. I just want to clear my mind that it does not require a main breaker. Thanks..
You can certainly argue that if you don't have more than 6 breakers in the panel that you are legal. Whether the AHJ actually accepts it is another thing. Strictly looking at the code, it is legal. There used to be a rule for "lighting and appliance" panel boards that required a main breaker but that went away when the "L&A" distinction went away.
Wow! I thought this was something I was missing. Hoping it was a Yes or No answer. Guess I'll have to bug the AHJ here again. I don't like doing anything the second time. Thanks a lot for all your input. I think that would be another thing the Code could verify a little clearer in the next Code. Thanks again..