I'm finding all sorts of conflicting information on this, some of which is hearsay, local, or outdated.
For an electric heater and air handler unit, with #6 wire, that will be either 50 or 60 amps, what type of device is code compliant to be the "readily accessible" disconnecting means?
This is for new construction and the unit is not in sight of the panel. NEC 2017 and IRC 2012 apply here.
Some say the breaker built in to the air handler is enough. Some say it isn't. Some say to use a non-fusible disconnect, like this. Others say that the door on the front make it not "readily accessible" and some inspectors will fail it.
Can you please tell me what the correct device should be and cite a code reference to support it?
Best Answer
The applicable NEC cite for a typical air handler of this nature is 424.19(A)(2) (424.19(A)(1) does not apply to most air handlers as the fan motor in them is over 1/8 HP):
Given that the motor controller in an air handler is going to be inside the air handler (it's the fan relay there), unless your air handler has a unit switch on the outside to serve as a disconnecting means, then you need a motor-rated disconnecting means in sight of the air handler. A non-fusible molded case disconnect like the one you linked works; you can also use a breaker-based "spa panel" type disconnect like the ones used for air conditioners provided the current rating is suitable, or even a subpanel if you wish to run the serviceman's receptacle and whatnot off the same set of wires as the air handler.
Also, having a door on a cabinet or cutout box does not violate "readily accessible" under the 2017 NEC: