Split Systems

[Fish Killer]

I have a dilemma with a Mitsubishi Split system. The nameplate says MOCPD is 50Amps and the minimum circuit ampacity is 28A... Currently fed with #10's, however being told I need #8's. Who's correct?

 

[GoldDigger]

If the adjustments and corrections applicable allow 28A to be carried by #10, then that is OK

 

[texie]

I have a dilemma with a Mitsubishi Split system. The nameplate says MOCPD is 50Amps and the minimum circuit ampacity is 28A... Currently fed with #10's, however being told I need #8's. Who's correct?

#10 it is, as it has an ampacity of 35 @75*. This would even be OK @ 60* if you are using NM cable.
As you probably already know, the wire size does not need to "match" the OCPD in this application.
Out of curiosity, who is claiming this is wrong?

 

[Fish Killer]

The inspector wanted to know if the minimum ampacity included the 125% motor rating as per NEC 440.32........

 

[GoldDigger]

The MCA takes all of that, including multiple motors if applicable, into account.

 

[Fish Killer]

So when does 440.32 come into play?

 

[ceb58]

The inspector wanted to know if the minimum ampacity included the 125% motor rating as per NEC 440.32........

The MCA takes all of that, including multiple motors if applicable, into account.

Agreed, the name plate tell you and the inspector what the manufacturer's engineers have determined to be the appropriate ratings.