400V rated Switch/relay

Discussion in 'The Projects Forum' started by hellomofo, Nov 1, 2007.

  1. hellomofo

    Thread Starter New Member

    Nov 1, 2007
    I'm looking for a switch that can handle 400Vac, 10ma and have a small footprint (can fit in a 1/2"x1/2" space). Any suggestions?

    Also, what is the difference between a relay and a switch (in general)? I found some relays that i can turn into switches but voltage rating was too low (250V). Aren't relays the same as switches? Both are used to "go from A to B".


  2. JohnBoy

    New Member

    Oct 30, 2007
    Do you have to switch 400VAC or can you switch a lower voltage point?

  3. niftydog

    AAC Fanatic!

    Jun 13, 2007
    Relays are electro-mechanical devices. They use an electromagnet to actuate the switch.

    A switch is part of a relay. But normally when one thinks of "a switch" it means a switch that is operated by hand.

    There are many, many types of switches and relays. I think you'd need to expand on your requirements before anyone can assist you properly.

    Do you need a single pole single throw switch? Double pole? Double throw? What are you switching? Is there inrush current? How often must it switch?

    Can you use a lower rated switch to operate a higher rated relay? Often to switch heavy loads one will use a small, manually operated switch to control a large relay. This does two things - it isolates the high voltage from the operator of the switch, and it allows you to use a sufficiently rated relay to safely switch the high voltage.
  4. hellomofo

    Thread Starter New Member

    Nov 1, 2007
    Yes, I can use a lower rated switch to activate the higher rated relay. The switch must switch at 400Vac max.

    The switch will be in a handle assembly that controls a RF generator that operates above 100khz. 400Vac is delivered through the handle. The purpose of the switch is to allow the user to change the active line. The user can deliver energy to line A, then switch to line B at any time, and back at anytime. From a mechanical perspective, the switch can be momentary or on-off. ... of course there are more ways to skin this cat, but the general idea is to be able to change the delivery of energy from one line to another.

    The problem I am running into is I can't find any off-the-shelf small/miniature switches rated at 400vac. Most are for the common 125 or 250V. Maybe I will look into solid state relays.

    I hope that describes the intended use of the switch. Thanks for your responses niftydog and john.

  5. beenthere

    Retired Moderator

    Apr 20, 2004
    Look into Panasonic APT series phototriac couplers and the AGH series SSRs. They are both rated for 600 VAC.
  6. John Luciani

    AAC Fanatic!

    Apr 3, 2007
    Is this for a measurement system or are you hot-switching the relay?

    For a measurement system check out http://www.cotorelay.com

    (* jcl *)