Trouble coming up with a demand factor

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jph320

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Cinnaminson nj
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Electrician
I need to pull a permit for a 3 phase 200amp panel installation ina auto body shop and they want to klnow the demand factor. The shop has an old single phase 100amp service now but it needs to be updated and changed to three phase for their need equipment. It will be 2 15hp motors and 1 5hp motor and 20 20amp convience outles. What is the easiest way
 
Demand factor for receptacles is 100% for the first 10kva, and then 50% for the rest.

There is no real demand factor in the NEC for non-HVAC motors to my knowledge. Are these existing? What function do they serve (air compressor, lift, etc)? Unless you can determine their usage and how long they are pulling a load, you'll be stuck at 100%. But if it is motor that only has a temporary load, then you could definitely reduce it.
 
The concept of a "demand factor" is that you are permitted to take credit for the probability that not all connected load will be running at the same time. In the example of the receptacle demand factor that Keri mentioned, it is considered probable that not all receptacles will have something plugged into them, and even those that do will not be running at full load 100% of the time. But the code's "permission" to use less that the total connected load is limited to the few specific circumstances that appear in the code. So unless your facility, and your equipment, has been given a demand factor, you don't get to use one. In your case, I think you have to use 100% of the connected load.
 
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