High amperage relay to control hot water heater, baseboard heat and misc other stuff


(Michael Cumming) #1

I am trying to fnd a 240v relay that can handle 20 to 40 amps. Would like a latching relay or even better, one with local control so that if the automation system dies, the loads can still be controlled. Anyone have suggestions on a product. I searched but am not sure what to buy …


(Crispin) #2

With loads like that you’re best rolling your own.

Disclaimer:with loads like that you’ll likely cause a fire if done wrong.

I would use a sonoff to drive a contactor which is designed for the load. You then have the option to include a switch in parallel with the sonoff to manually turn the contactor on.

If you need a diagram I can a bit later.

Edit:
Something like this is good https://www.screwfix.com/p/british-general-40a-dp-contactor/1836p


(Chris Baxter) #3

This should work for you:

https://www.amazon.com/gp/product/B00MBIRF5W/ref=ox_sc_saved_title_5?smid=A33RI86K4PO1EO&psc=1


(Crispin) #4

That’s a nice option Chris. I did not realise there are higher power ones.

I wonder if one can flash it with custom firmware.


(Michael Cumming) #5

Found another option on AliExpress

Easy to control with an ESP8266.

However, I would really like to find a latching relay.


(Craig Miles ) #6

Have you considered Thristor load switching rather than relays?