NEC 220.82(C)(4) Clarification

[PHA]

In regards to the 2011 NEC 220.82(C)(4):

I have a Multi-family apartment unit and I am wanting to size the apartment unit load center. It is 240V 1-phase and will be installing an electric DX split system (GOODMAN is the manufacturer). The manufacturer provides an MCA value of 41.3A for a unit equipped with a 7.3kw heat kit installed. My question is this: When applying 220.82(C)(4), Do you consider the manufacturer MCA value or the 7.3 kw space heating value? Please provide NEC code references backing this up.

The examples in the NEC Annex D do not seem to address a DX split system air handler that has a blower and an electrical heat kit. IMO - The MCA value needs to be considered because the 7.3kw strip heat and the blower motor will be operating at the same time. It is a forced air system and not a space heater placed inside an individual room. You cannot take these as non-coincident loads. You should not just be allowed to apply the 65% to the heater kw value in this instance, correct? Or am I missing the mark? Again, please provide code references as I need something concrete to fall back on. Thank you in advance for the help; it is truly appreciated.

 

[mwm1752]

220.82 for < 100 amps calculated load -- 41.3 amps = AC --- 7.3kw + blower x 65% = heat load which is larger & is your calcs over 100 amps per Part III

 

[PHA]

220.82 for < 100 amps calculated load -- 41.3 amps = AC --- 7.3kw + blower x 65% = heat load which is larger & is your calcs over 100 amps per Part III

Yes, the unit load center is 100A or greater.

Can you clarify how 41.3A is my Air conditioning value? I don't think that makes sense. The air conditioning comes from the outdoor unit which i did not provided information on as it is less than 65% of the indoor air handler that i am requesting clarification on. The 41.3 MCA value is for the air handler with blower and heat strip. In your calculation you are taking the heat strip and adding the blower; you are essentially taking the manufacturer's listed 41.3A MCA value that I referenced.

 

[mwm1752]

Yes, the unit load center is 100A or greater.

Can you clarify how 41.3A is my Air conditioning value? I don't think that makes sense. The air conditioning comes from the outdoor unit which i did not provided information on as it is less than 65% of the indoor air handler that i am requesting clarification on. The 41.3 MCA value is for the air handler with blower and heat strip. In your calculation you are taking the heat strip and adding the blower; you are essentially taking the manufacturer's listed 41.3A MCA value that I referenced.

Misread -- you seem to have all the answers