Electrical Retrofit — Working with Old Wires
Start clean and work safe when expanding off of existing circuits.
Extending existing electrical circuits to add additional boxes for a garage workshop can be made easier by using Electrical Metallic Tubing, or EMT.
Starting the retrofit is easy. Start by shutting off the circuits you’re going to tap. As California electrician CJ Nielsen explains in “Crash Course in Conduit” in FHB #273, he uses a breaker finder with a transmitter and receiver to locate which breakers he needs to turn off. To be safe, he checks the boxes he’s going to tap with two different testers, just to be sure they’re off before he removes them.
Then he removes the old devices and clips off any exposed copper so he can start fresh. Often, he finds wires terminated on the back of receptacles. There’s nothing inherently wrong about that—it passes code—but if the device fails, it can take down other devices on the circuit. Nielsen prefers to splice his connections with pigtails. This method ensures continuity within the circuit even if a device, such as a wall outlet, fails.
For even more information, check out this feature article, Crash Course in Conduit, in FHB #273.