I can't seem to locate any specific wording on proper wiring method for recepticle installation :ashamed1
n pigtails or direct methods
There isn't any-
Either method is fine as long it is done correctly- it boils down to preference.
Pigtailing is done a lot by commercial guys because you can replace a device without interrupting power to something downstream. Others claim pigtailing is better b/c the device isn't burdened with the load of the ckt vs using the screw terminals and there is less chance of failure.:roll:- of course the receptacle screw terminals are rated to handle whatever the rating is on the receptacle.
If there is a mwbc present at the receptacle, the neutral has to be pigtailed. And you always pigtail your egc on a feed thru device in a box.
Beyond that, Just follow the instructions that come with the device or whatever is spec'd out by boss or customer.