Bosch Type Relays

[rv_safetyman]

Jim Wilkerson posted this question on the old board:

A vendor recommends that I use two 12 volt relays in series to switch a 12 volt load and a 24 volt load. I thought that a 12 vdc relay indicated the coil voltage and current rating indicated the amount that can be switched. So, following that, it seems to me that I should use 24 vdc relays since the signal wil be 24 volts. If the relay has the correct load rating, it doesn't matter what voltage is being switched.

Or will 12 vdc relays work just finre?

Here is my reply on the new board:

If you are switching a 24V system with 12V, then use a standard 12V relay.  The coil is 12V, but the contacts can switch 24V or even 120V AC in some cases.

I have a data sheet that I put together that also gives you sources for the relays:

http://www.rvsafetysystems.com/Relay%20data%20sheet.pdf

Jim

[Oonrahnjay]

    I attempted to post on the old board but could not.  I apologized to Jim W because I had mis-read his original post and my answer was not correct for (what I think is) what he is trying to accomplish.  My post there was not correct and is not useful for Jim's needs.  I apologize to all.

[Brian Evans]

The way I do it is to select the relay voltage based on the control signal, and the current rating based on the amps that need to be switched.  There is usually a wide range of voltages that can be controlled by the relay up to a maximum current, but the control coil needs to be matched to the voltage or it can overheat or not switch reliably.

Brian