Operating instructions

Operating Instructions 27
2.5.3 Maintenance Bypass
The static switch is equipped with bypass breakers CB4 and CB5 to allow manual bypass of the
switch electronics to either input source in case of switch failure or for maintenance of the switch.
Through proper operation, the static switch can be bypassed without de-energizing the load using
a make-before-break switching sequence. However, the unit can be bypassed using a make-before-
break switching sequence only to the same source that the switch is switched to, as indicated by
the highlighted STS box on the Monitor/Mimic screen or the On Source message of the Source
Transfer screen. If the switch is not connected to the source to which maintenance bypass is
desired, follow the manual transfer/preferred source select instructions to transfer the static
switch to the desired input source. In case of source or switch failure, the unit should be bypassed
only to the current input source. For convenience, bypass instructions are displayed on the
Bypass Procedures screens.
To bypass the unit to the same source that the switch is connected to, make sure that the
bypass breaker interlock key (from CB4 or CB5) is in the key interlock of the desired bypass
breaker (CB4 or CB5).
Open (turn Off) the other source static switch input breaker (CB1 or CB2) and rotate the interlock
key to extend the bolt of the key interlock thus preventing that input breaker (CB1 or CB2) from
being closed. Remove the key from the input breaker’s interlock and insert it in the key interlock
of the desired bypass breaker (CB4 or CB5). The key from CB1 only fits into the interlock of CB5
and the key from CB2 only fits into the interlock of CB4. Rotate the keys in the bypass breaker’s
interlock to retract the bolt of the bypass breaker’s interlock. The bypass breaker key interlocks
require two keys, one from the opposite source’s input breaker (CB1 or CB2) and the bypass
breaker key. There is only one bypass breaker key, which allows only one bypass breaker to be
closed at a time. Close (turn On) the bypass breaker. Verify the breaker status on the Monitor/
Mimic screen.
To isolate the static switch, open the static switch input breaker (CB1 or CB2), rotate the inter-
lock key of the input breaker to extend the bolt, and open the output/isolation breaker CB3. To
return to normal operation from maintenance bypass, insert the key in the interlock of the
static switch input breaker (CB1 or CB2) from the same source as the closed bypass breaker.
Rotate the key to retract the interlock bolt.
Close the input breaker from the same source as the closed bypass breaker. Verify the input volt-
ages and the breaker status on the Monitor/ Mimic screen. Close the output/isolation breaker
CB3. Verify the CB3 breaker status and that the STS and Output boxes are highlighted on the
Monitor/Mimic screen.
If the STS box, Output box, and CB3 are not
highlighted, do not proceed. If the STS box,
Output Box, and CB3
are highlighted, open the bypass breaker (CB4 or CB5). Rotate the bypass
breaker interlock keys to extend the interlock bolt.
Remove the input breaker interlock key from the bypass breaker interlock and insert it in the
other source input breaker (CB1 or CB2) interlock. Rotate the key to retract the interlock bolt
from the other source input breaker.
Close the other source input breaker. Verify the other source input voltages and breaker status on
the Monitor/Mimic screen. Press the Alarm Reset to reset previous alarms. Verify that there are
no active alarms. If any active alarms are displayed, refer to 2.6 - Alarm Messages for a descrip-
tion of the alarms and possible causes. All active alarm conditions should be investigated and cor-
rected.
2.5.4 Normal System Shutdown
When the static switch is operating on static switch (not maintenance bypass), turn off the load
equipment per manufacturer’s recommendations. Open CB3 to turn Off the static switch output.
Open the input breakers CB1 and CB2. To completely de-energize the unit, turn OFF building
power to both inputs to the static switch.
When the static switch is operating on bypass, turn off the load equipment per manufacturer’s
recommendations. Open the bypass breaker (CB4 or CB5) to turn Off the static switch output. To
completely de-energize the unit, turn OFF building power to both inputs to the static switch.