Which of the following is a primary method of terminating a wiring device?

• A. Back wire
• B. Twist wire
• C. Solder
• D. Wrap-around

Answer: (A)

The concept tested is how wires are attached to a wiring device and which method is considered standard today. Back wiring means inserting the stripped conductor into a clamp or push-in slot at the rear of the device, where the internal mechanism holds it securely. This method is the primary choice because it provides a fast, solid connection with less risk of loose screws or frayed strands, and it keeps wires neatly tucked behind the device for easier installation and inspection. It’s commonly supported on modern outlets and switches, making it the typical, go-to termination method.

Wrap-around termination, where the wire is wrapped around a terminal screw, is an older technique. It can loosen over time due to vibration or improper tightening, which can lead to poor contact or arcing. Soldering a wire to a device’s terminal is generally avoided in field wiring because it requires heat that can damage insulation and device components, and it makes future terminal replacements harder. Twisting wires together is a method used for splices or creating pigtails, not for directly terminating a conductor to a device.

So, back wiring is the best answer because it aligns with modern practice for reliable, code-compliant terminations on wiring devices.