On Saturday, August 2, 2014 7:23:06 PM UTC-4, wrote:
On Sat, 2 Aug 2014 22:28:45 +0000 (UTC), Doug Miller

wrote:



wrote in :



On Sat, 2 Aug 2014 14:05:32 +0000 (UTC), Doug Miller

wrote:



wrote in :



And remember - if the unit draws a constant 26 amps, it is over-spec

for a 30 amp circuit (maximum 80% rated current for continuous use)



The term "continuous" has a clear, specific definition in the Code -- and an air conditioner

does not meet that definition.



You really should stop trying to give electrical advice.

OK - what does "continuous" mean?



"Continuous load: a load where the maximum current is expected to continue for three hours

or more." [NEC, Article 100]



What minimum duty cycle is

required for it to be "continuous"?



See above.



How long does the air conditioner

run on the hottest day of the year?



Immaterial. The only relevant question is, does it pull maximum current for three hours or

more?



Is the running current not

"continuous" in this case?



It does not appear to meet the NEC's definition of a continuous load -- a definition you're

clearly ignorant of.



Starting amps don't count. Do you KNOW what

the steady state running current of the AC unit in question is??



From the data posted by the OP, apparently it's 26 amps.



My assumption is the AC unit would draw 26 amps for more than 20 min

utes at a time, up to full time operation, it is to be connected with

a 3 conductor (including ground) flexible stranded cable.



Your assumptions are no more valid than mine, whatever they are -

unless you KNOW what current the unit draws and KNOW it will never

approach 100% duty cycle



Wrong yet again. I never said it would not approach 100% duty cycle, and that's not what's

meant by "continuous load".

If the AC unit runs at 26 FLA for 3 hours and 1 minute on the hottest

day of the year, it is over 80% and "continuous" by code, so the wire

needs to be derated to 80%., meaning it needs a larger cable.

You're confused again. The 26 amps is not FLA, it's the spec for the
minimum ampacity of the circuit. The rest is the wire size that will
support 26A. You're taking what was already calculated by engineers
and applying factors on top of the factors they already applied when
they did the UL listing.