|This may seem a little odd to
present in the context of woodworking tips, but I have wanted to share this
idea for a while -- making your own Ground Fault Circuit Interrupter extension
Most of us work in shops in our basements or garages, places that often have
damp or wet floors, or at least the potential for a lot of moisture. So this
topic isn't too far off the mark for people with the interests we share.
Here's how I got to thinking about this. A while ago, the
Woodsmith offices suffered some water damage from floods, so
there was clean-up to do. What we needed was an extension cord for a wet/dry
vacuum and a power washer. A ground fault protected extension cord would be the
safest kind to use. But an extension cord with a ground fault circuit
interrupter receptacle can be hard to find, and expensive to buy.
So we gathered all the parts to make our own GFCI extension cord. Note: This is
one of those projects that's best to complete before it's needed.
First, let me take a minute to explain what a ground fault protected circuit
is. It's one that's able to detect differences in current coming into and going
out of an electrical tool. If the current into and out of the tool isn't the
same, it means there's a short somewhere. This can be a dangerous situation if
you're operating a tool on a damp floor -- your body could become part of the
circuit and carry the leaking (and possibly deadly) current to the ground.
That's what's called a ground fault. A GFCI protected circuit will detect such
a fault and interrupt the flow of current before it can hurt you.
To make a GFCI extension cord, we started by gathering up all the parts from a
local electrical supply store. Note: Most of the parts are available from
hardware stores, but we wanted to use commercial grade parts for extra
durability when used outdoors. Altogether, we spent about $40.
The safety part of the extension cord is the GFCI receptacle. The one we used
is rated for 120 volts at 15 amps. The receptacle is mounted in an outdoor-type
Besides the safety features, what we liked best about this extension cord is
the heavy-duty cable. It's a 14 gauge, 3-conductor cable wrapped in a bright
yellow jacket. This a lot tougher than the 14-3 cable you're likely to find at
a hardware store. And it's more expensive, too. But for a short length (our
cord is only 16 feet long), it's only a few dollars more.
On one end of the cable is an aluminum connector that joins the cable to the
receptacle box. This grabs onto the cable so it can't easily be pulled out of
the box. It makes a water-tight connection, too.
At the other end of the cable is the plug. Here again, we chose a heavy-duty
component. It a three-prong plug with a connector that prevents the cord from
being pulled out of the plug.
It worked well during the clean-up, and now we use it any time we need an
extension cord in the shop, and when we're working outdoors on a project for
Go to Tip #47