TP-6836 4/14 49Section 7 Bypass/Isolation
7.4 Bypassing and Isolating,
150- to 400-Amp Switches
See Figure 7-6. Also see the notes after this procedure.
Hazardous voltage.
Will cause severe injury or death.
Only authorized personnel should
open the enclosure.
DANGER
Removing the transfer switch from bypass/isolation
models. Hazardous voltage can cause severe injury or
death. Bypass and isolate the transfer switch before removing
it from the enclosure. The bypass/isolation switch is
energized. Do not touch the isolation contact fingers or the
control circuit terminals.
1. Manual bypass handle
2. Disconnect s witch
3. ATS location handle
BYPASS TO
EMERGENCY
BYPASS OPEN
BYPASS TO
NORMAL
RELEASE
ISOLATE
TEST
AUTO
2
1
3
Figure 7-6 Bypass Switch Handle Positions,
150--400 Amp Switches
1. Check that the ATS is in automatic mode:
a. The ATS location handle is in the AUTO
position.
b. The manual bypass handle is in the OPEN
position.
c. The disconnect switch is in the AUTO position.
2. Bypassing the ATS:
a. Turn the disconnect switch to the INHIBIT
position.
b. Position the manual bypass handle to the same
power source as the ATS.
Note: The bypass switch uses safety interlocks to
prevent cross phasing.
3. Testing the ATS:
a. Bypass the ATS as described in step 2.
b. Move the ATS location handle to the TEST
position.
c. Turn the disconnect switch to the AUTO
position.
d. Run an automatic operation test as described
in Section 6.5. End the test before proceeding.
4. Isolating the ATS:
a. Bypass the ATS as described in step 2.
b. Move the ATS location handle to the ISOLATE
position; the ATS ISOLATE position lamp will
illuminate.
5. Removing the ATS:
a. Bypass and isolate the ATS as described in the
previous steps.
b. Move the ATS location handle to the RELEASE
position.
c. Disconnect the multipin plugs and external
connections from the ATS.
d. Lift the ATS out of its drawer.
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