Macurco GBC-2-24, Installation & Operation Manual

Page: 10 / 20

Macurco GBC Manual
REV – 1.2 [34-2900-0690-7] 10 | P a g e
3.2.2.1 Main Power Connection
Warning: When making connections, make sure the power is off.
The GBC offers two power input versions. GBC-X-24: 24 VAC or VDC and GBC-X-120: 120 VAC. Always check the
input power type marked on the top of the GBC Main PCBA prior to connecting power. See Figure 3-5 as an
example.
Figure 3-5 – GBC Board Diagram
There are three terminals for Power: Power, Return, Ground. See Figure 3-5. The power connections to the GBC
should be size AWG 18 (minimum) for short runs. For longer runs follow recommended power wire gauge
guidelines. Match the polarity for power connection, for the low voltage models there is a bridge rectifier, so it is not
polarity sensitive.
Wire Gauge
Maximum Run Length
(feet) (meters)
18 500 152
16 800 244
14 1250 381
Table 3-1 Recommended Wire Gauge
Note: Only connect the GBC to Class 2 power supply.
Note: It is recommended to use an independent transformer for powering the unit(s) due to possible interferences
from other devices on the same power supply.
3.2.2.2 Sensor Connections
There are two sensor connections on the GBC. These connections provide power to the respective units and
monitor the normally close circuit that controls the GBC. The GBC can support up to four Macurco 6-Series gas
detectors (350 mA max) in any combination. The sensors must be wired in series for the normally closed circuit to
operate correctly. See Figure 3-6 and Figure 3-7.
Note:
If not using Sensor Connection 2 with a gas detector a jumper wire or zero-ohm resistor is needed between
alarm and 24 V. A zero-ohm resistor is factory populated in the Sensor Connection 2; a jumper wire can be used as
in place of the zero-ohm resistor. See Figure 3-6.
X