Connect The High-Voltage Relays - Hach SC4500 User Manual

Terminal
L
N
Protective earth ground
Terminal
L
N 24 VDC return
Protective earth ground

3.3.4 Connect the high-voltage relays

Electrocution hazard. Always remove power to the instrument before making electrical connections.
Potential Electrocution Hazard. Power and relay terminals are designed for only single wire
termination. Do not use more than one wire in each terminal.
Potential fire hazard. Do not daisy-chain the common relay connections or jumper wire from the mains
power connection inside the instrument.
Explosion hazard. This manual is only for installation of the unit in a non-hazardous location. For
installation of the unit in hazardous locations, use only the instructions and approved control drawing
provided in the hazardous location installation manual.
Fire hazard. Relay loads must be resistive. Always limit current to the relays with an external fuse or
breaker. Obey the relay ratings in the Specifications section.
Make sure that the cable sheath goes through the inner side of the enclosure to keep the environmental
rating of the enclosure.
The instrument has two non-powered relays, each with a single-pole change-over contact. For AC
controllers, the wiring compartment is not made for voltage connections more than 264 VAC.
The relay terminals are located behind a high-voltage barrier in the controller enclosure. Do not
remove the barrier while power is supplied to the relay terminals. Do not supply power to the relay
terminals when the barrier is not installed.
18 English
Table 2 Wiring information—AC power
Description
Hot (Line 1)
Neutral (N)
Table 3 Wiring information—DC power
Description
+24 VDC
Color—North America
Black
White
Green
Color—North America
Red
Black
Green
D A N G E R
W A R N I N G
W A R N I N G
W A R N I N G
C A U T I O N
N O T I C E
Color—EU
Brown
Blue
Green with yellow stripe
Color—EU
Red
Black
Green with yellow stripe