Sub Panel Feed

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rsvped

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I have a 150 amp main breaker panel and cant locate what I am looking for in the code book. How many or what size breakers am I allowed to put off this panel. I would like to put 1-60 amp and 2- 100 amp breakers. Is this possible? How and where can I find it in the code in order to calculate this?
 
You can't find it because it isn't there. You can put as many breakers as will fit, and they can be as high a rating as you like. Put 14 breakers on a 100 amp panel, each breaker being a 150 amp three phase breaker, and you have not violated any code. What matters is the load that you put on the panel. You can't load a 150 amp panel beyond a calculated load value of 150 amps, no matter how many breakers of what size are used to feed the loads.

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Thanks

Thank you for that response. I did find that section in 240 about total amps, as I suspected I was right in what I was looking for. Keeping this in mind I know that the total load of all 3 sub feeds will only be in the 50 amp per phase range.
 
rsvped said:
Keeping this in mind I know that the total load of all 3 sub feeds will only be in the 50 amp per phase range.
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Whenever I see someone use the phrase "amps per phase," I cringe. It is an opportunity for mis-communication just waiting for an unsuspecting reader.

So to clarify, what I infer from your statement is that the total load on any single phase will be about 50 amps. That means the 150 amp panel will be loaded to about 33%. You don't add "50 amps on Phase A" to "50 amps on Phase B," then add that to "50 amps on Phase C," and somehow come up with a "total" of 150 amps. The total in this example is 50, not 150. Is that what you meant?
 
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No Sir, I know the total load is 50 amps per phase. I gave the customer my input on everything needed for his job. I am dealing with a situation where another contractor wants the job done with everything oversized. Starting with the generator, cable size all the way to the breakers. Then the customer gets input from the other contractor that the sum of sub feed breakers can not be greater than the size of the main breaker. To break it down a little bit more I have a total of 6 window A/C units (15A ea) 6 flourescent lights and 8 duplex recepticles, and all of this is spread through 4 structures. I know how to do it but trying to get the customer to understand what I am saying is a task on its own especially when they are listening to the stuff the other contractor is saying. By the way, I appreciate all your help. Thanks.
 
charlie b said:
You can't find it because it isn't there. You can put as many breakers as will fit, and they can be as high a rating as you like. Put 14 breakers on a 100 amp panel, each breaker being a 150 amp three phase breaker, and you have not violated any code. What matters is the load that you put on the panel. You can't load a 150 amp panel beyond a calculated load value of 150 amps, no matter how many breakers of what size are used to feed the loads.

Welcome to the forum.
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Code aside, what about practice. I am a volunteer for an organization that runs meditation retreats. As a journeyman electrician (industrial), most stuff I deal with is highly engineered. However, I am trying to estimate a service distribution panel that will feed numerous diverse structures. A commercial kitchen, a place of assembly, residential quarters, etc. I am capable of doing the calculations on the individual bldgs, but how does one estimate an acceptable distribution panel?
 
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