I have an IEC C14 power connector (like those on PC power supplies). The connector has an integrated DPST switch, however the power pins are not connected directly to the switch-- I have to do that myself.

My first question is: Why have a DPST switch? Why not just a single pole that I wire to the line voltage?

The second question is: Which side to I wire the hot wire to? One set of the pins on the switch are divided by a small plastic divider.

Here is a picture: IEC C14 connector


1 Answer 1


Both contacts have same rating so unless there is a designated marking or colored screws for convenience, they can be interchanged.

In some countries this universal PSU could be coming off a Y or delta 3 phase output rather than single phase to neutral. So DPST is universal but not needed for single phase.

Also minor current comes off unswitched line due to Common mode filter Cap to ground. (0.5mA rms max)

  • \$\begingroup\$ Can you explain that last line a bit more about the filter capacitor? \$\endgroup\$ Commented Jul 11, 2012 at 2:25
  • \$\begingroup\$ All line filters with Common Mode Chokes have a cap (shown as Cp x2) in 1st figure of pulseelectronics.com/download/3100/… ... to ground on each line to suppress CM noise. THe value for current depends on the line voltage in that area and may not exceed a current dictated by UL/CSA/CE as stated. \$\endgroup\$ Commented Jul 11, 2012 at 17:27

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