sizing breaker and conductor

[aaatraker]

we build machines where i work and the ee are driving me nuts about the size of breaker and wire i say they need, i need your help.

the machine has heaters and a laser and small servo motors.
feed is 208 3p 4w---- not balanced the heaters are 120 volt so the neut. has current from the heaters. the machine will run 24/7.

questions: this would be a cont.load because it runs more then three hours, correct? even if its not at full load?
i would reduce the breaker rating too 80% right?and base the size on the full load amp rating even if it doesn't draw that all the time?
the conductor rating would be times 1.25 because of the cont. load correct?

thanks
kurt

 

[charlie]

Re: sizing breaker and conductor

A manufacturer does not have any requirement to follow the NEC rules (they are for premises wiring systems, not machines). They may build whatever works and can get listed. Forget the Code rules and listen to the engineers, they will build the machines to meet NEMA requirements.

 

[aaatraker]

Re: sizing breaker and conductor

Yes they can and are doing that, where the nec comes in, is that i have to power production lines in the factory to build and test the machines. And how i hook up to the machine is how they will advise there customers to do it, so the rub is how they label the fla on the machine, because thats what i would use to size the breaker and conductors correct?

thanks
kurt