QOD For W/E 06-25-11 #3

Okay, since you asked for it here is a question not from an old exam that is a little more difficult just to mix things up …

The electrical feeder for an AC condenser is 10-2 W/G CU NM-B cable connected to a 35A breaker. The condenser label is shown in the attached picture. This installation is ?

Only one person took a shot at an answer … maybe you guys dont want tougher questions … :shock:

I liked it we all learn even those who will not vote .
Thanks for doing this … Roy

The correct answer is …

D. not a problem if the breaker is HACR rated

On the surface you might think that a #10 Cu wire shouldn’t be on a breaker rated more than 30A. But air conditioner circuits are special cases where the typical limitations on the wires dont apply (the equipment has additional internal protection for wires). In addition, the individual wires are typically rated for more than code table limitations.

Model codes specifically state that the feeder wires and breaker should be installed in accordance with the equipment label (e.g. IRC E3702.11 … http://publicecodes.citation.com/icod/irc/2009/icod_irc_2009_37_sec002_par011.htm)

The label states “Minimum Circuit Ampacity - 21.5” and "Max Crt Brk - 35… so the #10 NM-B feeder on a 35A breaker is Okay. But the breaker has to be HACR type per the label.