Speedfax 2017

Low-voltage Switchgear
Arc Flash Solutions
General
Other protection options
n Infrared Viewing ports
n Zone Selective Interlocking
n High Resistance Grounding
14
SWITCHGEAR
Infrared Viewing Ports
Infrared viewing ports allow maintenance personnel to
monitor temperatures of the cable and bus connection points
in the rear of the gear while it is energized and under load.
Excessive temperatures can be an indication of a problem
with a connection.
Zone Selective Interlocking
Zone Selective Interlocking eliminates any intentional time
delay in the event a fault occurs between two breakers in
adjacent zones. In the schematic to the right, representative
time delay values are shown for the breakers in each zone.
If a fault occurs on the load side of the downstream breaker,
the ZSI system enables the upstream breaker’s delay and
allows the downstream device more time to independently
clear the fault. If the fault occurs on the line side of the
downstream breaker (between two zones), the delay in the
upstream breaker will not occur. This allows the fastest
tripping time for faults and will reduce the amount of arc
energy which may be released. The ZSI function is available
for short time delays and ground fault delays.
Infrared viewing ports
High Resistance Grounding
Research has shown that a high percentage of arc faults
start as a phase to ground fault. High resistance grounding
systems minimize the available phase to ground arcing
current.
Zone Selective Interlocking
A high resistance grounding system reduces the magnitude of
phase to ground faults. This will reduce the mechanical stress
on equipment for the most common of faults and will reduce
the magnitude of energy released.
PH1 PH2 PH3
PH1 PH2 NEUT
3-CLF
2-CLF
ROD
TEST
RELAY
PULSE
RELAY
RES
RES
TEST
RELAY
PULSE
RELAY
TEST
RESISTOR
RES
METER
RELAY
RES
SYSTEM
SWITCH
RES
RES
SYSTEM
SWITCH
AM
W
NORMAL
TEST
RESISTOR
RES
METER
RELAY
RES
W
NORMAL
WIRE LOOP FOR
PORTABLE DETECTOR
R
FAULT
AM
R
FAULT
G
PULSE
WIRE LOOP FOR PORTABLE DETECTOR
G
PULSE
CONTROL
CIRCUIT
PULSE SW
CONTROL
CIRCUIT
PULSE SW
14-94
Siemens Industry, Inc. SPEEDFAX Product Catalog