EvanZabEE
New member
- Location
- Neenah, WI, USA
Hi All,
I'm currently working with a brewery that got a prototype glycol chiller from a startup company to use for their brewing system. Problem is it's not UL approved, but all of the components inside are, so working with the Inspector, they decided to wire all the components individually. They currently have qty 14 hots, all on 20 amp breakers, all 12 awg in a single 1" conduit.
Name plate states the following;
Overall Chiller Assembly
Voltage 208/230
Phase 3
Condensing units
Compressor RLA 13.7A
Compressor LRA 73.0A
Fan Motor FLA 2.6A
Recirc Pump
FLA 1.75A
LRA 13.6A
Process Pump
FLA 4.5A
LRA 33.2A
I'm wondering how this applies both to Article 440 as well as derating for multiple CCCs in a (1 in) conduit.
I'm thinking only the hermetic motor-compressors fall under 440, and that running 12AWG on 20A breakers for each is sufficient. 440 states that conductor ampacity must be >125% of compressor RLA. 125% x 13.7A = 17.125A; 12AWG is sufficient. For protection, it states that it cannot exceed 175% of RLA, which is 23.975A, next down would be 20A breakers.
But, this configuration is not derated appropriately. Derating for 14 CCCs is 50%, so it'd have to be derated to 10A breakers. That would not be sufficient given above.
The options as I see them are either
A) run a 2nd conduit: with 7-9 hots, the derating is 70%, which would be 17.5A, which can be rounded up to 20A breakers due to 240.3(b).
or
B) Rerun 10awg wire. With 40A ampacity, 20A breakers would satisfy the 50% derating for 14 CCCs in a conduit. Also fulfills conduit fill req of <= 18 10 awg in a 1 in conduit.
Thanks for any input!
Evan
I'm currently working with a brewery that got a prototype glycol chiller from a startup company to use for their brewing system. Problem is it's not UL approved, but all of the components inside are, so working with the Inspector, they decided to wire all the components individually. They currently have qty 14 hots, all on 20 amp breakers, all 12 awg in a single 1" conduit.
Name plate states the following;
Overall Chiller Assembly
Voltage 208/230
Phase 3
Condensing units
Compressor RLA 13.7A
Compressor LRA 73.0A
Fan Motor FLA 2.6A
Recirc Pump
FLA 1.75A
LRA 13.6A
Process Pump
FLA 4.5A
LRA 33.2A
I'm wondering how this applies both to Article 440 as well as derating for multiple CCCs in a (1 in) conduit.
I'm thinking only the hermetic motor-compressors fall under 440, and that running 12AWG on 20A breakers for each is sufficient. 440 states that conductor ampacity must be >125% of compressor RLA. 125% x 13.7A = 17.125A; 12AWG is sufficient. For protection, it states that it cannot exceed 175% of RLA, which is 23.975A, next down would be 20A breakers.
But, this configuration is not derated appropriately. Derating for 14 CCCs is 50%, so it'd have to be derated to 10A breakers. That would not be sufficient given above.
The options as I see them are either
A) run a 2nd conduit: with 7-9 hots, the derating is 70%, which would be 17.5A, which can be rounded up to 20A breakers due to 240.3(b).
or
B) Rerun 10awg wire. With 40A ampacity, 20A breakers would satisfy the 50% derating for 14 CCCs in a conduit. Also fulfills conduit fill req of <= 18 10 awg in a 1 in conduit.
Thanks for any input!
Evan