Building a Home Garage Workshop

Construction & Design (p2)

 

Utilities

ELECTRIC - When it comes to building your own "ultimate garage", its important to anticipate current and future electrical requirements. This starts by bringing in adequate power with a dedicated subpanel in the garage for effective distribution. A small garage can get by with 40-60 amps whereas a larger shop with extensive equipment will need 100-200a. Machine and woodworking shops should also anticipate the need for 3-phase power for some of their larger equipment (5hp+).

 

I personally like Square D and Cutler-Hammer load centers (with CH or QO series breakers). The above Square D 100a panel has 30 spaces, all filled at this time. All circuits are run with 12 gauge wire or larger.

The 8-zone digital timer handles the outdoor pond pumps and landscape lighting and the receptacle box to the left of the timer is for a future EV charging station. The conduit is capable of carrying a 30-50a (220v) circuit back to the main panel with an interlocked fume extraction system to evacuate battery fumes during charging.

Shops running voltage sensitive equipment and controls should consider some sort of power conditioning, surge suppression or UPS backup (with auto or manual transfer switch)....additional details.

 

With regard to electrical outlets, your garage subpanel should have at least one 20 amp circuit for each of the following......

  • 20a/120v lower outlets - for drop lights, battery chargers, small fans and most electrical devices with long cords. These outlet boxes should be located 12-24" above the floor and the receptacles GFCI protected (check with your local electrical contractor or inspector). I like to use GFCI breakers since any power reset is done at the subpanel...no need to chase down a GFCI that may have tripped somewhere in the shop.

  • 20a/120v upper outlets - generally used for tools, test equipment and other electrical devices on the workbench countertop. These should be located 42-50" above the floor. I generally set the bottom of the outlet boxes at 42" (with a laser is quick and easy) to make it easier for the drywall crew, especially when they're laying 10-12' panels horizontally. Check with your local building office for GFCI requirements. Devices within a specified distance of a shop (or any) wet sink will require GFCI protection.

  • 20a/120v standalone outlet - "dedicated circuit", upper, lower or both. I use a different color receptacle to easily identify these outlets. Shop vacs, small compressors, and other 8amp or higher loads should be powered through standalone circuits. Audio, video and sensitive test equipment should also be on dedicated circuits to minimize interference issues.

  • 240v lower outlets - wired with 10 gauge to support either a 20a or 30a receptacle. Make sure to use the properly sized breaker in the subpanel. Welders often require 50a receptacles and should be planned for accordingly if you expect to use one in your workshop.

  • 240v upper outlet (NEMA 14-50) - wired with 6 gauge (50a) to support a Level 2 EV Charging Station. Tesla offers an 80a wall connector for use with their cars equipped with dual chargers providing up to 58 miles of range per hour to the vehicle batteries. This should be run to a dedicated 100a circuit. (Note - the 40/50a is presumably easier on the vehicle batteries. Check with your car manufacturer to determine best charging rate and if their is any impact on battery warranty.)

 

 

There are 3 other devices which require outlets in the garage. These loads can easily be handled by any of the general power circuits above. This includes...

  • Wall clocks - use "clock hanger" outlets with recessed receptacles.

  • Garage door electric openers - on the wall or ceiling depending upon the type of opener used.

  • Wall-mount televisions and monitors - I typically put these on circuits tied in with the rest of my electronics with isolated ground protection.....see below

 

 

 

 

Ultimate Workshop Receptacles - When it comes to choosing a 120v duplex receptacle for my garage projects, I'm a big fan of Pass & Seymour's Industrial Heavy Duty line. Their 5362A (CR6300 for the yellow corrosion resistant version) is essentially a 20a "hospital grade" straight blade device at half the price (with Ultimate Garage discounts). See additional details and photos.