Grounded Tools: Tools with 3-Prong Plugs
Tools marked with
Grounding Required
have a 3-wire cord and 3-prong grounding plug. The plug
must be connected to a properly grounded outlet. If the tool should electrically malfunction or break
down, grounding provides a low resistance path to carry electricity away from the user, reducing the
risk of electric shock. (See Figure A.)
The grounding prong in the plug is connected through the green wire inside the cord to the grounding
system in the tool. The green wire in the cord must be the only wire connected to the tool’s grounding
system and must never be attached to an electrically live terminal.
Your tool must be plugged into an appropriate outlet, properly installed and grounded in accordance
with all codes and ordinances. The plug and outlet should look like those in the following illustration.
Double Insulated Tools: Tools with Two-Prong Plugs
Tools marked
Double Insulated
do not require grounding. They have a special double insulation
system which satisfies OSHA requirements and complies with the applicable standards of
Underwriters Laboratories, Inc., the Canadian Standard Association, and the National Electrical Code.
(See Figure B.)
Double insulated tools may be used in either of the 120-volt outlets shown in the following illustration.
Extension Cords
⚠
WARNING
USE A PROPER EXTENSION CORD. Make sure your extension cord is in good condition. When
using an extension cord, be sure to use one heavy enough to carry the current your product will
draw. An undersized cord will cause a drop in line voltage, resulting in loss of power and cause
overheating.
Be sure your extension cord is properly wired and in good condition. Always replace a damaged
extension cord or have it repaired by a qualified person before using it. Protect your extension
cords from sharp objects, excessive heat and damp or wet areas.
Grounded tools require a 3-wire extension cord. Double Insulated tools can use either a 2- or 3-
wire extension cord.
As the distance from the supply outlet increases, you must use a heavier gauge extension cord.
Using extension cords with inadequately sized wire causes a serious drop in voltage, resulting in
loss of power and possible tool damage.
The smaller the wire’s gauge number, the greater the capacity of the cord. For example, a 14-
gauge cord can carry a higher current than a 16-gauge cord. Minimum extension cord wire size is
shown in the following table:
