13.8 Primary
4160 Secondary.
Resistor added in Field (Not Factory) done all the time.
From XO on Transformer Wire insulated for 4160 to Resistor.
They have From Load of resistor to Ground bare copper.
I feel per 250.186 (B) it must be 4160 insulated to Ground even after resistor . Because its a Neutral going to ground.
250.186 (C).
It doesn't Change from a Neutral just because it goes thur a resister. Yes it then feeds switchgear which feeds 2 large motor loads. Its on the riser I sent you some time back.
I called the Manufacturer of the Resistor Gard & he said he'd get back to me.
