The new junction box and exposed work cover for the electrical outlet and light switch are prewired before installing in the attic. This project is continued from How to Wire an Attic Electrical Outlet and Light.
NEC 300.14 – Minimum Length of Conductors
I have to replace the old light switch and electrical outlet boxes by the attic stairway because the electrician cut off the ground wires, which are too short to make pigtail connections. Recall the wires must be at least 6 inches long at the box and extend at least 3 inches outside the box per NEC 300.14 requirements. To remedy this, a new 4 inch square junction box will be mounted a several inches lower on the 2×4 framing to expose at least 6 inches of NM-B 14/2 cable in the new junction box. I’ll also combine the convenience duplex outlet & toggle switch in the junction box using an exposed work cover. The 4 inch square junction box is highlighted in yellow in the wiring diagram:
Combining the duplex outlet and light switch in the square junction box will save space.
Exposed Work Cover for Electrical Outlet and Light Switch
It’s getting warm in the attic, so I decided to do all the pre-work I can in the workshop.
The electrical parts for the job are:
- Raco 906C Exposed Work Cover for use with 4 inch square box
for one Toggle Switch and one Duplex Receptacle - Leviton #5252 Heavy Duty Outlet 15 Amp, 125 Volts
- Leviton #CSB1 Single Pole Toggle Switch 20 Amp, 120/277 Volts
- 4in x 4in x 2-1/8in steel square box with stud mount bracket
- Halex #05103B 3/8in Clamp Connector for Non-Metallic Cable
Electrical Outlet and Light Switch Break-away Ears
A minor problem is the duplex outlet and light switch will not fit inside the exposed work cover because the “ears” catch:
The fix is simple: break off the switch and outlet ears by bending back-and-forth with a pliers. Note the stamped line at the base of break-away ears for this purpose:
Remove and discard the mounting screws included with the outlet and switch. The exposed work cover includes two Philips head screws that mate with the hex nuts. Use the flat head screws to mount the toggle switch as shown here:
After breaking off the ears, the duplex outlet and toggle switch will properly seat in the exposed work cover:
I’ve temporarily mounted the outlet and switch in the exposed work cover to illustrate the mounting:
The hex nuts are required for mounting electrical outlet in the exposed work cover:
The exposed work cover is 1/2 inch deep for extra room in the 4 inch square steel junction box:
The exposed work cover mounts to the 4 inch square junction box with the two junction box screws on opposite corners:
NM Cable Clamps
Two NM cable clamps are needed to protect and secure the NM-B 14/2 cable at the 4 inch square junction box. The Halex 3/8 inch cable clamps fit the 1/2 inch diameter knockouts (1/2″ K.O.) in the steel junction box. Two clamp connectors are required: one for the line-side cable (from the circuit breaker) and one for the load-side cable (to the attic light).
The 1/2 inch junction box knockouts are removed by firmly rapping the tip of screw driver on the edge opposite the metal tab to bend it open, then moving it back & forth with pliers a couple of times to break it free:
The NM cable clamps are attached to the junction box. I’ve also prewired the electrical outlet pigtails and toggle switch line-side and ground pigtails (reference the wiring diagram):
I’ll take the parts up to the attic for mounting and wiring in How to Wire an Attic Electrical Outlet and Light – Part 2.
Thanks for reading,
Bob Jackson
