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Extension Cord Has Extra Wire
Your site was most helpful... but...
I was replacing an extension cord plug but when I opened it it had 4
wires! A green, black, white and a RED!
What do I do with the red wire??
Hope you can help me.
Thanks.
Mark
The
wire you have is 3-conductor with ground. It is intended for 120 volt
AND 240 volt applications such as supplying a sub-panel.
All you need for a plain extension cord is 2-conductor with ground.
When I worked in hotel maintenance we used to make up dozens of
3-conductor extension cords to supply power to the various exhibits at
trade shows or to live bands that were playing outdoors.
If the plug you are installing is an ordinary 15 Amp plug, then you can
ignore the red wire. The proper approach is to cut back the red wire a
little bit and wrap the end with electrical tape so it cannot touch any
metal.
You also need to be sure that the individual conductors inside the cable
are not too big for the plug you are using. The cable should have
printing that states the wire gauge & combination, such as 14/3 or
12/3. The first number is the gauge of the conductor, the second number
is the quantity of current-carrying conductors (which should be 3 in
your case). Number 12 wire (which can carry 20 amps) may not fit into a
connector rated at 15 amps (which is what ordinary household outlets can
accept.) But some heavy-duty 15 amp connectors (i.e. male or female cord
ends) may accept number 12 wire. Home Depot sells such connectors.
This
cable is capable of being much more than an ordinary extension cord, so
if you have any special uses (such as powering a live band, or a
sub-panel for a construction job-site) you might want to set it aside.
When used as a 120/240 volt cord, the red wire is hot, just like the
black:
- There would be 240 volts between the red and black.
- There would be 120 volts between red and white
(neutral) as well as 120 volts between black and white.
- Green is ground as usual.
- Plugs and female ends for these special cords are completely different
from everything else around the house. The plugs are rated for different
current (amperage) levels. Many of these connectors are
"twist-and-lock" type that cannot be pulled apart easily.
There are all sorts of connectors, and none of them are cheap!
Bruce W. Maki, Editor.
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