Live/Work

Sample Shop Power Layout

Taken from “Setting Up Shop” by Sandor Nagyszalanczy.

Some comments and suggestions from the book include running tools at 200v instead of 110v (if rewiring is an option). The reason for this is that 220v machines run at half the amperage of 110v motors. Another recommendation is to locate outlets at between 42-50″ high on the wall. 42″ will clear workbenches, while 50″ will allow a sheet of plywood to fit under the outlet – nice!

Getting Power to Machinery

Routing power to shop machines can be tricky with slab-on-grade construction, especially for machines located in the middle of the space. Here’s two ways to handle it:

Most books recommend putting floor-mounted pugs in a raised box – this helps prevent accidental shorts and sawdust collecting in the plug holes. However, I’m not a fan of metal boxes popping out of the floor. It’s easy to trip on them, and if you ever move a machine, the plug can present a real obstacle. Plus, if you ever wanted to convert the space to “open living,” these pop-up plugs would be ugly.

I prefer the drop-down model or a brass, covered plate (especially if the floor is stained concrete)

Calculating Power Needs

In order to determine the size of the shop sub-panel, it’s a good idea to figure the individual amperage of machines used in the shop. Factor in the reality that some machines will run concurrently (like table saws and jointers) and thus should be on separate circuits. It’s also a good idea to put the lights on their own dedicated circuit so that a tripped saw breaker doesn’t leave you in total darkness. Here’s a chart of some common shop tools and their amperage:

* indicates tool not currently owned

Determining Amperage based on Horsepower

Here’s a handy chart to help determine the power needs based on the horsepower and voltage. Amperage estimates are approximate:

This entry was posted Saturday, February 3rd, 2007 at 7:39 pm and is filed under Building Materials, Shop. Both comments and pings are currently closed.