Serice Calc ? - 20 amp cont use circuit

[jimmyglen]

My very smart code instructor gave us a question on a SERVICE calculation for an office

We were asked to size the service and determine total load in VA

We were told the sq ft with 615 duplex recpt, 110' of multi outlet assembly etc etc etc

We were also given (4) 20 AMP CONT. USE BRANCH CIRCUITS as a part of the total load (we were told that this WAS NOT a recpt load and not subject to demand factors)


It was my thought that we should take the 20 amp x 1.25 and then times the voltage (120v) --- I cited Art 220.12A ---that would give us 4 x 2400va x 1.25

my instructor told that that since you cant put an actual 20 amp load on a 20 amp circuit that our calculation should be like this
4 x 1920Va x 1.25
citing Art 210

After thinking about this WAY too long, I decided that really its just bad practice to give a branch circuit load and not a specific load (or at least the branch circuit load should be a recpt load)


What say you?

 

[Smart $]

Depends on exactly how the load was stated. As given by you, "(4) 20 AMP CONT. USE BRANCH CIRCUITS", can be interpretted two ways: either as 4 branch circuits having an ampacity of 20A per circuit, each with a maximum continuous load OR 4 branch circuits with an actual continuous load of 20A each. Stating these are not receptacle loads even further adds ambiguity towards the determination. Furthermore, the possibility exists, however unlikely, that continuous duty equipment could be used. Without a stipulation whether this is the case or not, any answer is mere speculation based on assumptions :grin:

Additionally, as with most disagreements, there is always more than one point of view. We are only hearing your side of the story, and in your words.