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 ..
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
This should work for you:
That’s a nice option Chris. I did not realise there are higher power ones.
https://www.aliexpress.com/item/30A-Wifi-Relay-Switch-AC-110V-220V-1CH-DIY-Automation-Modules-Smart-Home-Receiver-and-Universal/32901481781.html?spm=2114.search0104.3.1.5bf64647ndn0t0&ws_ab_test=searchweb0_0,searchweb201602_3_10065_10068_10130_10547_319_317_10548_10696_10192_10190_453_10084_454_10083_10618_10307_10820_10301_10821_538_10303_537_536_10059_10884_10887_100031_321_322_10103,searchweb201603_51,ppcSwitch_0&algo_expid=ec383a68-2d14-4fbb-a805-101d54695546-0&algo_pvid=ec383a68-2d14-4fbb-a805-101d54695546
I wonder if one can flash it with custom firmware.
Found another option on AliExpress
Easy to control with an ESP8266.
However, I would really like to find a latching relay.
Have you considered Thristor load switching rather than relays?