Multiple integrations kits on single low-voltage 3rd party thermostat
When somebody is requesting a quote/plan with a single low-voltage thermostat and area is over 22Amps, then only 240V Integrations kits and of course 240V mats need to be used.
Multiple integrations kits can be connected to a single low-voltage thermostat only if kits are 240V. We can't mix 120V and 240V Kits or multiple 120V Kits on a single low-voltage thermostat.
Diagram is here: NEST-INTEG-MULTI-240V-WD-A
IF ONLY 120V IS AVAILABLE THEN RC840T-120 (INTEGRATION KIT 120V) RELAYS NEED TO BE ON THE SAME PHASE/POLE - NEST-INTEG-MULTI-120V-WD-A (Diagram for 120V option is not public)
IF ONLY 120V or ONLY HOT LEG connected to RC840T-240, TRANSFORMER WILL ONLY PROVIDE ~13.5V which is not enough for a typical low-voltage thermostat that needs 24V.