Honeywell TC300

Thermostat powered by public transformer 25
If shielding is used, the shielding of each individual bus segment should be sepa-
rately connected at one end to the earth.
Thermostat powered by public transformer
Fig 14. Thermostat Powered by Public Transformer
If the controller shares the power transformer with TC300, the connection style
depends on the power design of controller and please consult the technical sup-
port to avoid short circuit.
If TC300s are connected to a controller and share a public transformer, please
make sure the 24VAC power wires are connected to the thermostats in the same
sequence, as showed in the above figure. The red wire is connected to the C termi-
nal and green wire is connected to the R terminal. Incorrect connection style can
cause a short circuit.
If any device on the network is connected to earth ground or not electrically iso-
lated, connecting the C wire to the corresponding device’s RS485 GND is recom-
mended.
If shielding is used, the shielding of each individual bus segment should be sepa-
rately connected at one end to the earth.