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Joined: Dec 2004
Posts: 1
W
Wardey Offline OP
New Member
Trying to size a service for a chiropactors office and not sure on the demand for an X-Ray machine. The X-Ray Tech say's he needs an 100 Amp 220V circuit. Here's what I have existing:
100 Amp 3 Phase Service w/ 1 Alum Conductors

So do I figure the X-Ray machine at 100% demand?

And my load calcs would be:
12 receptacles @ 180VA = 2160
640sq.ft. @ 3 VA = 1920
Heat @ 10,000 VA
Sign Ckt. @ 1200 VA
X-Ray Machine @ 24,000VA
Total 39,280 VA

39,280VA / 240V = 163.66 Amps / 1.73 = 94.60 Amps

Correct? The 100 Amp service should be suffecient?

Thanks !!!

Joined: Mar 2003
Posts: 849
Y
Member
if your using 240 x 1.73 it must be a high leg delta??
IF ITS A 120/208 Y (most common) it be 208 x 1.73 =359.84
Just checking.

Joined: Dec 2000
Posts: 4,291
Member
Yoop,
Wrong answer.

If 208 volts you DIVIDE it by 1.73
Not MULTIPLY it.

39,280VA / 208V / 1.73 = 109.15 Amps




Joined: Mar 2003
Posts: 849
Y
Member
39280 divide by 359.84 =109.15962
Sure looked like devideding to me?????

1.73 x 208= 359.84
39280 Divided by 359.84

Last edited by Yoopersup; 03/11/09 05:31 PM.

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