On Wed, 23 Jul 2008 11:11:34 GMT, (Doug Miller)
wrote:

In article , Bob Engelhardt wrote:
I'm in the process of modifying an electric clothes dryer. I want to
switch 21A, 240v current, but I don't have, and can't find, a switch
with that capacity.

But, as I understand it, switches are rated for the current that they
can *break*.

They are rated for the current they can carry.

My application will never require the switch to break the
current - that will be done by the dryer's timer.

Also, in a closed-contact situation, I'm thinking that paralleling 2
sets of contacts will double (more or less) the current capacity.

Assuming you're talking about North American standard wiring, that is NOT
correct. The two 120V legs that comprise a 240V circuit are not in parallel;
they are in *series*, and the current is the same at all points in the
circuit.

So, if I use a 2 pole 15A rated switch, parallel its poles, & never
break the current with it, could it carry 21A?

No.

You are not reading what the OP said. He did NOT say he would switch
both lines. He said he would tie the two sets of contacts together,
back to back (that's parallel) to share the load on ONE WIRE.
As long as there is nothing 110 on the drier, this will work, even if
it is not the right way to do it (he'll still have one line "hot" when
the "powwer" is shut off.

So the short answer is it will work. The not QUITE so short answer is
it is not the right way to do it, and I would recommend you do not.

What's the switch for if the timer will shut it off?

Why not use a "contactor" made for the job, if you need to switch it?

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