Note: Secondary-disconnect terminals are
numbered 1-16, from right to left.
The automatic spring-charging features of
the circuit breaker must be checked.
Control power is required for automatic
spring-charging to take place.
1. Open control-power circuit by opening
the control-power disconnect device.
2. Install the circuit-breaker end of the
split-plug jumper (if furnished) to the
circuit breaker as shown in Figure 5:
Split-plug jumper connected to circuit
breaker. The split-plug jumper is
secured over the circuit-breaker
secondary contacts with thumb screws.
3. Install the switchgear end of the split-
plug jumper to the secondary-
disconnect block inside the switchgear
cubicle as shown in Figure 6: Split-plug
jumper connected to switchgear. The
jumper slides into place and
interconnects all control power and
signal leads (for example, electrical trip
and close contacts) between the
switchgear and the circuit breaker.
4. Energize (close) the control-power
5. Use the close and trip controls (refer to
Figure 1: Type 38-3AH3 vacuum
circuit breaker front panel controls on
page 8) to first close and then open
the circuit-breaker contacts. Verify the
contact positions visually by observing
the OPEN/CLOSED indicator on the
6. De-energize control power by
repeating Step 1. Disconnect the split-
plug jumper from the switchgear
before disconnecting the circuit-
7. Perform the spring discharge check
again. Verify the closing springs are
DISCHARGED and the primary contacts
of the type 38-3AH3 vacuum circuit
breaker are OPEN.
Installation checks and
Final mechanical inspections without
1. Make a final mechanical inspection of
the circuit breaker. Verify the contacts
are in the OPEN position, and the
closing springs are DISCHARGED.
2. Check the upper- and lower-primary
studs and contact fingers shown in
Figure 7: Circuit breaker primary
disconnect. Verify mechanical
condition of finger springs and the
disconnect studs, check for loose
hardware, damaged or missing
primary-disconnect contact fingers and
damaged disconnect studs.
3. Coat movable primary-contact fingers
(refer to Figure 7: Circuit breaker
primary disconnect) and the
secondary-disconnect contacts (refer
to Figure 23: Construction of
secondary shunt release (shown
charged) on page 30) with a light film
of Siemens contact lubricant number
4. The type 38-3AH3 vacuum circuit
breaker is ready for installation into its
assigned cubicle of the metal-clad
switchgear. Refer to removal
procedures and install the circuit
breaker into the switchgear.
5. Refer to the switchgear instruction
manual for functional tests of an
installed circuit breaker.
Figure 5: Split-plug jumper
connected to circuit breaker
Figure 6: Split-plug jumper
connected to switchgear
Figure 7: Circuit breaker