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Installation instructions for mains wire-in protectors
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Remote indication
A remote indication of the reduced protection state is provided
for linking the protector to a building management system,
remote telemetry, PLC or directly to an indication light or buzzer.
The unit has both a normally open and a normally closed volt
free contact, powered by an ‘active‘ relay.
The terminal for the volt free contact accepts 1.5 mm
2
cable
and is located on the bottom of the ESP unit. It has three
terminals, marked:
14 = NO
= Normally Open
12 = NC
= Normally Closed
11 = C
= Common
The normally open (NO) contact is open when the ESP unit is
healthy and power is present. The normally closed (NC) contact
is closed when the unit is healthy and power is present.
As well as providing warning of the reduced protection state,
the normally closed volt free contact can also be used to signal
power loss on one or more phases, eliminating the need for
special relays.
See Figure 17
.
The ESP units remote indication is rated at 1 amp, 250V AC.
A minimum load of 10mA, 5V DC is required to ensure reliable
contact operation.
Figure 17. Operation of normally closed (NC) and normally
open (NO) volt free contact.
While the relay is active and functioning correctly the LCD display
will show the 'normal operation' screens - RLY ACTIVE.
Maintenance
Maintenance should be conducted at least once a year and
also following lightning activity. Visually check:
(i) Visual status indication lights/LCD display
(see Status indication for interpretation)
.
(ii) Condition of connecting leads and terminations.
Unit Healthy
Reduced or
No protection
Power Present
Power Absent
NO
NC
NO
NC
OPEN
CLOSED
CLOSED
OPEN
CLOSED
CLOSED
OPEN
OPEN
TNB 1639 ESP D1 Instructions (Final Art) new size 1/4/10 09:51 Page 34
