More power can improve safety

The farm shop may be the hub of winter activity for many farms. However it takes plenty of good lighting and electricity to clean combines, repair fall tillage equipment and prepare for spring planting. Power tools, compressors and welders all draw a considerable amount of power, and upgrading your electric service may also be a wintertime project.

If your farm shop is short on electrical service, we’d recommend an electrical service of 200-amp, 240 volt as the minimum for farm shops, and that may not be sufficient for larger facilities. Where motors 1/2-HP or larger will be used, install a separate circuit to serve no more than two 1/2-HP motors, and no more than one 1-HP or larger motor.

If welding equipment is used in your shop, install a 50-amp or larger 240-volt outlet for the welder. Two or more outlets properly located will make it possible to use the welder in most locations when working on machines inside the shop. Have at least one welder outlet near the large door so welding can be done outside. Put the service panel near a walk door for emergency shut off access and plan for expansion with more branch circuits and heavy-duty wire sizes.

I know most farmers do their own wiring, but unless you are thoroughly familiar with wiring, always have a qualified licensed electrician do the work. Electrical wiring will need to be approved by an electrical inspector before electrical service will be connected by a power supplier. Remember that 120 volts can be very dangerous and improper wiring often is the cause of serious fires. Install 120-volt duplex outlets every 4 feet along work benches and every 10 feet along walls at a 4-foot height from the floor. If power tools are used any distance from the walls, outlets can be installed in the floor or suspended from the ceiling.

Ground fault circuit interrupters are recommended on all single phase 15- and 20-amp outlet circuits. A GFCI senses a fault in a circuit to protect the user from electrocution. The National Electrical Code requires GFCIs on all 15- and 20-amp receptacle outlets installed on the outside of a building and near wet areas. Ground fault interrupters are available as portable units, on extension cords, as circuit breaker interrupters, or as receptacle units.

Lighting in the shop should include plenty of light above a workbench for detailed work. For task lighting, use double-tube, 4-foot fluorescent fixtures mounted about 4 feet above the workbench and positioned toward the front half. For general indoor lighting, provide at least 20- foot-candles of illumination at floor level. That’s equivalent to one double-tube, 4-foot fluorescent fixture for every 80-100 square feet of floor area, assuming an 8-foot mounting height. Light-colored ceilings and upper walls help.

For general outdoor lighting, use 200-400 watt high-pressure sodium or metal halide lamps, mounted at a 15-25 foot height, with photocell control. Install exterior lights no more than 125 feet apart for the best lighting conditions. Place a 150-watt spotlight, with motion sensor activation, on one or both sides of the entrance door instead of over the door, to keep out flying insects.

For additional information on circuit sizing and safety, consult the Wiring Handbook for Rural Facilities at For more safety information go to

Stanley (Jay) Solomon is a member of the Safe Electricity Advisory Board University of Illinois Extension Educator, Environmental and Energy Stewardship working Jo Daviess/Stephenson/Winnebago Unit, Building R, Highland Community College, 2998 W Pearl City Rd Freeport, IL 61032 • 815-235-4125 •