Re: GFCI for Engine block heaters
The NEC does not define "public." But it does define "qualified person." In my view, the one is anyone who is not the other.
In other words, the "public" is not intended to mean a person who is not an employee. It means a person who is not trained in the means and methods of safely working around, or even just being around, electrical equipment. The employees who park in this particular garage could well be accountants or truck drivers or administrative staff, none of whom can be expected to know what a GFCI does or why it is used.
If these block heaters are tripping the GFCI receptacles, then there is a reason. You can't solve the problem by eliminating the safety feature that alerts you to the problem, and that protects you against the problem.
Charles E. Beck, P.E., Seattle
Comments based on 2014 NEC unless otherwise noted.