Crash Course in Conduit
An electrician shares the basics of bending, fastening, and connecting electrical metallic tubing.
After buying a fixer-upper north of San Francisco, a carpenter friend of mine wanted to install a workbench in the garage to tackle some projects. The problem was, there weren’t enough outlets to make efficient use of the space. When he asked me for help, one solution immediately came to mind: surface-mounted boxes connected by electrical metallic tubing, referred to as EMT.
Although the sleek, industrial look of EMT is finding a niche in industrial interiors, where it’s used as a design element to add interest to a room, it’s mostly called upon for its low cost, durability, and ease of installation. It has become a standard for garages or workshops, where it’s tough thin-walled steel or aluminum construction can take a beating. It’s often used to retrofit new electrical outlets, switches, and other devices onto existing walls. It’s especially useful on concrete or block walls, and in other situations where obstructions don’t allow wiring to run in the walls.
In my friend’s garage, the wiring is typical of residential homes—nonmetallic sheathed cable hidden behind drywall. While there are no obstructions, using EMT meant I didn’t have to open up the walls (or patch the drywall afterward), and it’ll be easy to run additional electrical devices off of it in the future.
Laying out surface-mounted EMT
Before bending any conduit, install all your electrical boxes—both the new boxes and the extension rings on the existing boxes that you’re going to tap. All measurements will reference off these.
When deciding where to put new boxes, envision how the conduit is going to get there from existing boxes. It’s best to avoid putting new boxes in places that require lots of bends. The electrical code only allows 360° worth…