What device is required when the total connected load exceeds the maximum rating of the thermostat?

An extra relay, to power the contactors, Thermostat will activate low current or sensitive relays in turn to control the contactors.
Update, Are you talking about 24 volt control or line voltage(120 or 240)?

Quote:

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Originally Posted by Stratmando

An extra relay, to power the contactors, Thermostat will activate low current or sensitive relays in turn to control the contactors.
Update, Are you talking about 24 volt control or line voltage(120 or 240)?

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I'm talking about 120

Still a relay. 120 volt coil Relay or Contactor/Contacts should be rated for the load, 20 or 30 Amps, thermostat will connect coil voltage to relay or contactor, relay or contactor will handle Load.
Need help with wiring?

Quote:

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Originally Posted by Stratmando

Still a relay. 120 volt coil Relay or Contactor/Contacts should be rated for the load, 20 or 30 Amps, thermostat will connect coil voltage to relay or contactor, relay or contactor will handle Load.
Need help with wiring?

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No thanks, I'm good.

Good Deal, the Thermostat should only see the load of the relay. Take Care