Q. I have always thought that the best way to wire a receptacle is to use a pigtail lead from the supply wires to the receptacle. My electrician prefers to run the supply wires, and also the wires to the downstream receptacles, to the screw terminals at the back of the receptacle. When receptacles are wired his way, with the feed-through current going through the receptacle, can downstream electrical loads overheat the receptacle?

A.Steve Campolo, vice president for engineering at Leviton, responds: UL specifically tests receptacles for the ability to safely carry downstream current. This testing is usually conducted at 20 amps, since a 15-amp receptacle can be wired on a 20-amp circuit and thus carry the 20-amp feed-through current. As long as the receptacle is rated and UL-listed for feed-through wiring, as well as properly installed, it should be safe as intended by UL’s Standard for Safety (UL 498), which covers receptacles.

The pigtail method transfers the connection point from the receptacle to a wire nut. So instead of the feed-through current going through the receptacle, it goes through the wire nut. Which junction is better? It’s hard to say; it depends on the skill of the installer. The methods should work equally well as long as the installation is properly made in accordance with the manufacturer’s instructions, and in compliance with all provisions of the National Electrical Code and any UL listing requirements that may apply.

Wiring a Receptacle