Relay 24 V appliance I want to use a switch and an Arduino to "power" a 24 V DC appliance and I am not really sure what relay to use for this.
So I need the relay to be able to switch it on and off, but I have not really been able to find any that do it for 24 V DC, only for mains.

Can I use a mains relay or is there special one for 24 V.
I have all tried searching for the problem but haven't really found anything that helps. I'm probably searching for the wrong thing.

I am new just started learning electronics and stuff.
Thanks.
Most relays have their ratings written on them. You can also find all the information you need in the datasheet for that relay. Search for the part-nr in your favorite search engine. 

You need to find a relay that can handle at least 24Volt DC. Not AC as relays can handle a much higher voltage at AC than they can at DC. 

You also need to check how maximum current your appliance draws. Make sure the relay is rated for at least that amount of Amps.

For example; the picture below shows a relay that's rated for 10A and 30VDC