Disconnect size

[teco]

Hello,
I have two separate air compressors rated 480 volts at 172 amps each. We will tap a 400 amp feeder already in the area to feed both machines. My question is, can I use a 200 amp fused disconnect switch for each set of tap conductors. The switches will be within 10'of where the tap is made. HP is under 125 each.
172 x 1.15 = 197.8 ? I'm asking about the switch, not the conductors.

 

[iwire]

Yes on the 200 amp swiches

But 172*1.25+172=387

Are there already loads on this 400 amp feeder?

 

[infinity]

Wouldn't a 200 amp disconnect switch already have a HP rating? Just curious where the 172 amp load comes from for this motor under 125 HP @ 480 volts.

 

[teco]

Iwire,
No, spare 400 amp not currently connected to anything. I should mention these are wye/delta start machines. My concern is a max fuse capability of a 200 amp fuse. I do not have the wall space for two 400 amp switches. These things a like coffins.

 

[teco]

Wouldn't a 200 amp disconnect switch already have a HP rating? Just curious where the 172 amp load comes from for this motor under 125 HP @ 480 volts.

Yes, 150 at 600v and 125 at 480v I believe. The compressors are the air cooled enclosed type. There are good size cooling fans and other equipment built in. Total nameplate rating on each machine is 172 amps at 480v.