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Wiring an indoor extension cord to a small switch? Answered

Hi -

I need to take an indoor extension cord like this and wire it to a switch like this. I'm assuming I can just cut one of the two wires within the extension cord and connect either end to a prong on the switch.  Actually, I'm almost positive that will work. The real question here: is it safe? So, will this switch be able to hand the electricity from the outlet running through it?




4 years ago

It will work but in order to be safe it needs to be mounted in a panel or enclosure to keep it stable when turning on/off. I recommend you get an inline rocker switch specifically for such a purpose. You can get inline switches at most hardware stores for $2 or $3.


The switch is rated for 3 amperes,  which corresponds to a load, the thing to which you are delivering power, not greater than about 115 *3 = 345 watts.

Also the two wires in this extension cord are called "hot" and "neutral", and the usual way this is done is to put the switch in series with the "hot" side.  This is done so that when the switch is open, no part of the wiring inside the load is connected to "hot".  (Naturally when the switch is closed, the hot wire does get connected to the load. )

The attached picture shows what I am describing, i.e. the switch that interrupts the current is placed on the "hot" wire.

It is physically possible to put the switch on the neutral wire, and the switch will be able to turn the load on and off, but it's just slightly less safe to do it that way. 

I think for an extension cord, like the one in the picture you linked to, the hot side is connected to  the small slot, and the neutral is the wider one. 

Of  course you can test for which wire is hot using a multimeter, set to measure AC voltage, on an outlet with slots for hot, neutral, and ground.  The voltage between hot and neutral measures around 120 (or maybe 240 depending on where you live) VAC.  The voltage between hot and ground also measures around 120 (or maybe 240 depending on where you live) VAC.  The voltage between neutral and ground should be very close to zero.


Yes that's all you have to do. The switch is rated for 125VAC @ 3A. So it will be fine for things like lamps but you wouldn't want to plug a vacuum cleaner or microwave into the cord.

Thanks for the speedy reply! So it would work for a lightbulb wired to an outlet? Using one of those adapters for using light fixtures with standard outlet plugs.