Computer Power Supply Switch Question
 

I have a 9amp 250 watt AT style power supply without a switch. It has 4 wires plus a ground. I am having difficulting find a AT style switch that has the 4 lugs (double pole/single throw).

Can I use a single pole/singe throw switch? How would it be wired with the 4 wires plus the ground? What VAC and AMP rating would it need to be?

Thanks for you help
Matt

Computer Power Supply Switch Question
 

Use a double pole single throw switch. You should have the following colors:

brown and blue -- these are the live and neutral feeds from the 110v power cord and are always hot when the PS is plugged in.

black and white -- these wires carry the AC feed from the switch back to the power supply and will be hot only when the PS is plugged in and the switch is turned on.

green or green/yellow -- earth ground

When the switch is off, the black and white should show no voltage. If your want to match the poles, make sure the blue contacts the white and brown contacts the black when the switch is closed.

Just make sure the blue and brown don't cross when the switch closes -- since most computer components run on gray smoke, letting the smoke escape will render them non-functional.

Regards,

Andrew

Computer Power Supply Switch Question
 

Andrew's right - AT computer power supplies NEED a double pole, single throw switch because they interrupt both wires from the AC supply.

In theory, you could modify the power supply by using two SPST switches. Just use two side by side, glue/tape them together so you throw both switches at the same time.