I have a job where the heat trace cable for some water piping and a convenience outlet have a seperate disconnect from the rest of the HVAC unit.
It is 115VAC running from the residence on a 20 amp circuit. This enters our disconnect which is a 230VAC 30A non fused disconnect. From the bottom of this disconnect the conductors run to a terminal block and then split off into two circuits. One for the heat and one for the outlet. Each is individually fused.
The question I have is whether I should open only the ungrounded conductor per 380-2(b), or open both per the exception to that rule? Both conductors if ran through the two poles of the disconnect would be broken at the same time.
I am a proponent of breaking both lines since the heat tape is wrapped around water lines (3" copper, or black steel at the pumps), but others at my company do not think the exception should apply.
I would appreciate any knowledge that could be offered.
