Refrigeration Equipment

[jimdavis]

I'm working on an industrial project. One of the pieces of equipment that I need to supply power to is a process chiller. Am I correct in assuming that the "minimum circuit ampacity" given on the nameplate is based on FLC x 125% and no further increase for continuous load is necessary? And does the OCPD size need to be based on 175% of this value in accordance with 440.22(A)?

 

[Smart $]

I'm working on an industrial project. One of the pieces of equipment that I need to supply power to is a process chiller. Am I correct in assuming that the "minimum circuit ampacity" given on the nameplate is based on FLC x 125% and no further increase for continuous load is necessary? And does the OCPD size need to be based on 175% of this value in accordance with 440.22(A)?

You assume correctly.

Typically a nameplate which indicates minimum circuit ampacity also indicates maximum overcurrent protection device rating. If not specified, then as stated in 440.22(A).

 

[jimdavis]

Thank you. You guys always seem to have the right answers.

 

[StarCat]

MAX rating on HVACR machines

MAX rating on HVACR machines

I'm working on an industrial project. One of the pieces of equipment that I need to supply power to is a process chiller. Am I correct in assuming that the "minimum circuit ampacity" given on the nameplate is based on FLC x 125% and no further increase for continuous load is necessary? And does the OCPD size need to be based on 175% of this value in accordance with 440.22(A)?

You are always better off going with the MAX nameplate rated protective device on HVACR gear, especially if it is single phase.
This is due to the difficulty of starting compressor loads of this type and the starting characteristics they exhibit. Notably under lower line voltage situations.
A recording style AMMETER such as a Fluke 87 is very telling on these matters as you can see exactly what the peak inrush is.
I have been on countless jobs where the original service had to be upgraded to the MAX due to this exact matter.
Single phase jobs will often times require Hard Start components in addition, but that is the HVACR guys job to determine if problems still exist.
If you have installed the MAX breaker size then you cannot be blamed for breakers tripping on startup.
AS an installing electrician you will always save youself headaches down the road by following this one simple rule.

 

[iwire]

You are always better off going with the MAX nameplate rated protective device on HVACR gear, especially if it is single phase.

I agree and even when using the max OCPD you can still use the MCA for the wire sizing assuming voltage drop is not an issue.

 

[augie47]

A word of caution.... I see a lot of refrigeration equipment where the max overcurrent calls for FUSE with no notation of a circuit breaker being acceptable.

 

[iwire]

A word of caution.... I see a lot of refrigeration equipment where the max overcurrent calls for FUSE with no notation of a circuit breaker being acceptable.

Is that still happening? I figured by now most would not specify.

But great point to bring up.

 

[augie47]

Is that still happening? I figured by now most would not specify.

I'd say 75% of the chest type and walk-in coolers and freezers with separate condenser units call for "max fuse" on the condensers.
Another thing I see missed a lot deals with the evaporators calling for a max OXCP of 15 amps.

 

[lielec11]

I'm working on an industrial project. One of the pieces of equipment that I need to supply power to is a process chiller. Am I correct in assuming that the "minimum circuit ampacity" given on the nameplate is based on FLC x 125% and no further increase for continuous load is necessary? And does the OCPD size need to be based on 175% of this value in accordance with 440.22(A)?

I always double check by doing my own calculation per 430.24, sometimes the HVAC manufacturer doesn't do the calculations correctly. Additionally (and personally only), I typically use 1.5 instead of 1.25 for my largest motor for starting currents when I calculation MCA.