xguard
Senior Member
- Location
- Baton Rouge, LA
We have quite a few chiller replacements coming up, 80 ton-ish.
One example. 80 ton chiller, 480VAC, 3 phase, 6 compressors (RLA 23.1 x 3, 26.9 x 3), 6 fans (RLA 3.3 x 6) for a total of 169.8 amps. Then 169.8 x 1.15 = 195.27 So a 200 amp disconnect would work for this. [current values from nameplate of chiller].
Horsepower rating: 169.8 amps, table 430.250, 150 HP equivalent. Both Siemens and Square D 200 amp disconnects with dual element time delay fuses are rated 125 hp @ 480 vac. This disconnect wouldn't work for us if we wanted to use it to disconnect the chiller under load but we could still use one of these disconnects if we install a label that says "do not operate under load."? (430.109(E)).
1. Is this correct?
2. If so, how common is it to go up in disconnect size to the 400 A for example that has a hp rating of 250 @ 480 VAC?
[I left off the LRA condition to keep it short, it worked out to 200 HP].
One example. 80 ton chiller, 480VAC, 3 phase, 6 compressors (RLA 23.1 x 3, 26.9 x 3), 6 fans (RLA 3.3 x 6) for a total of 169.8 amps. Then 169.8 x 1.15 = 195.27 So a 200 amp disconnect would work for this. [current values from nameplate of chiller].
Horsepower rating: 169.8 amps, table 430.250, 150 HP equivalent. Both Siemens and Square D 200 amp disconnects with dual element time delay fuses are rated 125 hp @ 480 vac. This disconnect wouldn't work for us if we wanted to use it to disconnect the chiller under load but we could still use one of these disconnects if we install a label that says "do not operate under load."? (430.109(E)).
1. Is this correct?
2. If so, how common is it to go up in disconnect size to the 400 A for example that has a hp rating of 250 @ 480 VAC?
[I left off the LRA condition to keep it short, it worked out to 200 HP].