Question about the 10'/10% rule - the exception states "adjacent portions of
a circuit." How does this apply to an underground conduit run, where there
are two ends exposed to higher ambient temperatures than the length in the
ground?
For example, what if there is 100 feet in the trench, and 7 fe
As I read the rule, that 100' in the trench allows you to go 10' above
grade on each side while just worrying about the ampacity in the 100'
section (be sure to check that your terminals are OK). For 200' in the
trench, you're still looking at 10' above grade on each side. The rule
doesn't say
Hi Wrenches -
Does anyone know what the specific working clearance requirements are for
disconnects switches (there might be a difference between fused and
non-fused) and meter sockets?
I've historically gone by the typical conservative approach found in NEC
110.26, ie 3' in front and 30" wid
I think this answers a question I was
pondering. If a conduit is run on standoffs over
a roof, the temperature is cooler than on the
roof, so the derating of the wire's ampacity is
less. It would appear from 310.15(A)(2)
Exception that it would not be necessary to limit
the ampacity of the
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