Inspector says that article 680.21(4) only applies to pool motors. If a pool heater is connected to this circuit it can not be fed with NM cable within the interior of a one fanily dwelling, it would have to be in conduit. Why would a heater make a difference?
The inspector is right. 680.21 does just apply to "motors". If you really want to argue with him, ask him to point out the section that specifically describes the wiring method to a "pool" heater. The pipe rules are in 680.21 "motors", 680.23 "underwater luminaires" and 680.27(A)(2)"underwater speakers".
Heaters show in in 680.26 "bonding" but not in the branch circuit wiring articles as far as I can tell.
Mine (Sta-Rite Max E Therm) has an electrical igniter, a blower and an electrical gas valve that is interlockled with the pool motor along with an interface to the pool control computer, if installed. The instructions say it should be bonded. A lug is provided for the purpose.
George It speaks well of you that you're remembering your days of contracting and i'm sure that you're able to focus on true safety issues rather than the letter of the book and its most stringent interpretation.
Greg a Power Pile system is a system that involves a gas valve and a millivolt operated pilot light safety. Hold the spring loaded button down and allow gas to flow to the pilot light and once the bimetal sensor probe (in the flame) is heated up it generates enough voltage (millivolts) to keep the pilot light solenoid energized and thus the main gas valve and associated thermostat will operate. Standing pilot goes out-and this would prevent the main valve from operating and no gas escapes or creates any hazard. Around these parts, this is refered to as a Power Pile system. Might be a slang expression.
I would not see this as an electric pool heater needing bonding but they bond it anyway.