Honeywell W7761A Owner's Manual page 23

TRANSFORMER
120/240 VAC
IMPORTANT
If the W7761A Device is used on Heating and Cooling Equipment (UL 1995 US only) devices and the transformer
primary power is more than 150 volts, connect the transformer secondary to earth ground, see Fig. 14.
Fig. 14. Transformer power wiring details for one Excel 10 used in UL 1995 equipment (U.S. only).
IMPORTANT
Notes on power wiring:
All field wiring must conform to local codes and ordinances.
To maintain NEC Class 2 and UL ratings, the installation must use transformers of 100 VA or less capacity.
For multiple controllers operating from a single transformer, the same side of the transformer secondary must be
connected to the same input terminal in each device and the ground terminals (1 on the W7761A) must be
connected to a verified earth ground for each device in the group. See Fig. 13. (Device configurations are not
necessarily limited to three devices per transformer.)
For the W7761A Device (which has Triac outputs), all output devices must be powered from the same transformer
as the one powering the Excel 10 W7761A Device.
Use the heaviest gauge wire available, up to 14 AWG (2.0 mm
power and earth ground connections.
To minimize EMI noise, do not run Triac output wires in the same conduit as the input wires or the E-Bus
communications loop.
Unswitched 24 Vac power wiring can be run in the same conduit as the E-Bus cable.
24 VAC
W7761A
25 24
1
EARTH
GROUND
Fig. 13. Power wiring details for two or more Excel 10s per transformer.
LINE VOLTAGE
GREATER
THAN 150 VAC
TRANSFORMER
1 IF THE W7761 CONTROLLER IS USED IN UL 1995 EQUIPMENT AND
THE PRIMARY POWER IS MORE THAN 150 VOLTS, GROUND ONE
SIDE OF TRANSFORMER SECONDARY.
EXCEL 10 W7761A INPUT/OUTPUT DEVICE
W7761A
25 24
1
EARTH
GROUND
24 VAC
1
EARTH
GROUND
1
EARTH
GROUND
2
) with a minimum of 18 AWG (1.0 mm
23
W7761A
25 24
1
EARTH
GROUND
W7761A
M10088
M10090
2
) for all
74-2699