Code question

[Jim bradford]

I’m also an air-conditioning contractor as well as an electrical contractor. We installed a package unit with an MOP of 70 and MCA of 54.6 . The home had number six wire run from the panel to the unit so we put a 60 amp breaker in the panel. The inspector failed me said it has to have a 70. I thought as long as my breaker was between MOP and MCA and the wire was sized correctly for the MCA I was good.

 

[infinity]

The inspector is incorrect. The minimum is just that unless the unit specifies a number higher than the MCA.

Welcome to the forum.

 

[Elect117]

Ask the inspector what MOP stands for and ask what code section says you can't install less than the maximum.

You are correct. Wire is sized to MCA and protection at or less than MOCP

440.4(B), First sentence.

 

[Jraef]

M in MCA = MINIMUM,
M in MOP = MAXIMUM.
Inspector is incorrect / ignorant of the above facts and/or their meanings.

That said, I like to go with Maximums, because if it nuisance trips on startup, you will have to eat the return call to replace that breaker.

 

[bmcgovern5]

As an electrical inspector, I would pass your job. You met the MCA with I'm assuming is #6 romex @ 55 amps in Table 310.16 (60 deg). If the unit nameplate did not specify a minimum OCP greater than 60 amp, I see no reason to fail the job.

 

[infinity]

As an electrical inspector, I would pass your job. You met the MCA with I'm assuming is #6 romex @ 55 amps in Table 310.16 (60 deg). If the unit nameplate did not specify a minimum OCP greater than 60 amp, I see no reason to fail the job.

Correct, there is no reason to fail the installation because it is code compliant.