Hach SC4500 User Manual page 21

Connect each relay to a control device or an alarm device as necessary. Refer to
Table 4 to connect the relays. Refer to
the trigger condition for each relay.
Refer to Specifications
and the low-voltage input/output circuitry.
The largest gauge wire the power and relay plugs are rated for 1.5 mm
terminals accept 0.75 to 1.5 mm
with an insulation rating of 300 VAC or higher. Insert each wire into the appropriate terminal until the
insulation is seated against the connector with no bare wire exposed. Tug gently after insertion to
make sure that there is a secure connection. If necessary, remove the connector from the PCBA for
easier wiring of the terminals. Flexible wires must have a crimped ferrule or a pin type terminal on the
end.
Note: Make sure that all of the cables stay below the cable limit line printed on the PCBA to prevent interferences
with the high-voltage barrier.
The current to the relay contacts must be 5 A (resistive only load), 1250 VA 125 W (resistive only
load) or less. Make sure to have a second switch available to remove power from the relays locally in
case of an emergency or for maintenance.
For AC controllers, use the relays at high voltage. For DC controllers, use the relays at low voltage.
Refer to Specifications
high and low voltage.
Relay terminal connections to the mains circuit in permanent connection applications must have
insulation rated for a minimum of 300 V, 90 °C (194 °F). Terminals connected to the mains circuit
with a power cord connection must be double insulated and rated 300 V, 90 °C (194 °F) at both the
inner and outer insulation levels.
Figure 10 Connect the relays
Terminal Description
1 Relay 2, NC
2 Relay 2, common
Configure the high voltage relays
on page 3 for the relay specifications. The relays are isolated from each other
2
(18 to 16 AWG) wire (as determined by load application). Use wire
on page 3 for the relay specifications. Do not configure a combination of both
Table 4 Wiring information—relays
on page 31 to configure
2
(16 AWG). The relay
Terminal Description
4 Relay 1, NC
5 Relay 1, common
Figure 10 and
English 19