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Electrical Calculations #76682 03/12/01 06:44 PM
Joined: Mar 2001
Posts: 5
A
AFFELEC Offline OP
Junior Member
How do you calculate the service requirements for a hotel with multiple electric heat / a/c units. There are approx. 22 of them. I believe you would take th KW each times number of units with standard amperage formula times 125%, but not sure. These units would be on their own service with nothing else.

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Re: Electrical Calculations #76683 03/12/01 07:04 PM
Joined: Oct 2000
Posts: 5,389
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sparky Offline
Member
220-15 seems to be what your after. Note it says "computed at 100%" , which only means no derating of more than 1 unit to me.

Re: Electrical Calculations #76684 03/12/01 07:26 PM
Joined: Mar 2001
Posts: 5
A
AFFELEC Offline OP
Junior Member
i belive your right thanks . if my math is correct then 5,150 watts x 22 , 208 v ea 2wire , 22 amps ea. , total 110 kw w/ 3 phase factor then i should come up with 305.32 amps so a 400 a service 120/208 3 phase would be more than adequate however we put in 2 main lug panelboards 42 cir (225 a)becuase the 2 pole breakers could only occupy 40 spaces ea panel . might put in a 3rd to lighten load on ea of these.then again the extra capacity might be nice w/ a 600 a service and distribution board


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