I scavenged this relay and I think it will work as a main kill switch to a water heater element, but I wanted to get a confirmation.
Potter & Brumfield T92S7A22-120
Here's the datasheet.
It says max contact current rating is 30A and max contact voltage rating is 600V. It's a DPST relay. Should this be fine for both legs going to a 240V 5500W water heater element? I would drive the relay coil with 120V and a switch to act as a kill switch to the heater element. I'll be doing the PID control with an SSR, this is just a main safety on/off switch.