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Joined: Mar 2003
Posts: 849
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Fire pump 20hp & booster pump 3/4 hp.460volt3phase

20hp=27amps LRC=145 amps
3/4 hp=1.6 amps LRC 12.5 amps
Disconnect Size 145 +12.5=157.5
240.6 next size up 175amps
175amp disconnect switch
The way I read it from the fire pump locked rotor sized disconnect switch to fire pump controller wire sized at 125 %
27plus 1.6=28.6x125%=28.6
according to the code 175 amp disconnect switch with 30 amp wire from switch to fire pump controller then to the mtr. code handbook 2002 pages 975-976.
Please comment . Thank u

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