Proper Sizing and Use Of Extension Cords

One of the most common mistakes that is made during any home improvement, remodeling or construction project is using the wrong size extension cord to supply electricity to power tools.  This mistake is made be contractors and home handymen alike.

Complete listing of Extension Cords

 

 

 

 

 

 

Figure 1 - 12/3 outdoor 100' extension cord

Using undersized, by gauge of wire, extension cords, is a sure way to burn out power tools and other electrical devices.

Why?

The thinner the wire in the extension cord, the higher the resistance, and the more power that is lost in the extension cord itself, rather than being delivered to the power tool.

There are a few reasons that undersized extension cords are used:

• convenience - it is the extension cord that is readily available.

• using a multi-ganged head and plugging in more than one power tool

• the smaller the wire size, the less expensive the extension cord.

Table 1 provides an indication as to the amperage draw of common power and gardening tools.  This chart is meant to be a guideline only and one should read the exact amount of power required on the power tool or electrical device label.

Table 1 - Current Requirements For Common Power & Gardening Tools
Item	Estimated Power Required	Item	Estimated Power Required
Table Saw Miter Saw Radial Arm Saw Concrete Mixer	15 - 20 Amps	Circular Saw Roto-Hammer Lawn Mower	10 to 15 Amps
Electric Drill Saber Saw Sawzall Router Chain Saw	5 - 10 Amps	Weed Whacker Hedge Trimmer BBQ Rotisserie	2 to 5 Amps

Table 2 - Extension Cord Lengths
Wire Gauge	Current (Amps) Requirement
	1 to 5 Amps	5 to 10 Amps	10 to 15 Amps	15 to 20 Amps
18	Should not be used
16	Max length 100 feet	Max length 50 feet
14	Max length 100 feet		Max length 50 feet
12	Max length 100 feet
10	Max length 100 feet

If it is necessary to run an extension cord farther than 100 feet than you should go up one size.

Complete listing of Extension Cords