Two of the four number 16s have 240 Volts across them. The generator goes into the crank & run mode with this 240 is removed (power failure). The 240 Volts is also used to power the generator's battery charger.
The other two number 16s have 12 Volts DC across them when the Generator comands the transfer switch to go into the generator mode (non utility).
I have seen some people (mostly home owners) use 18-4 thermostat wiring (very bad move) when the factory supplied wiring is to short.
Hope you find this info help full.
