Hi,

i need to use a relay to switch 12v supply but it will need to cope with upto 200amp, im havign trouble finding a single relay that can cope with this, my question is could i use for example 2x100amp relays to share the current or 4x50amp ect ect?

 

A starter solenoid should be adequate for that load. Prices seem to be in the $20 range.

 

im in the UK and all the starter selonoids i can get hold of are only 100amp.......can you use the idea i suggested or have i got this completly wrong?

 

You want a contactor... Try Albright in England. http://www.albrightinternational.com

 

they seem very expensive but sound like what i need..........thanks

just out of curiousity is it possiable to share the load over relays?

 

I wouldn't recommend sharing the load over relays (neither does UL or any other safety agencies although I have heard of situations where the accept that construction)

And Albrights contactors really aren't that expensive... You should be able to get one in the $20-30 USD range.
I really like their latching coil versions so you aren't creating heat keeping the coil energized all the time but it does require different circuitry.

 

I concur mcgyvr - albright has a good commercial range - you just have to select the appropriate one for the job at hand.

Sharkey, what is your application? Can you control the current through the relay by say only allowing substantial current flow when the relay is on (and not switching). If the number of switchings required is minimal, and you want a quick fix then you should be able to get away with parallel contacts, and even under-rated contacts, especially if load isn't inductive or incandescent - it comes down to contact wear and heating and reliability.

Ciao, Tim