Vertiv Liebert MBX, Installer/User Manual

Page: 15 / 34

2.5 Tap-Off Box
The Tap-Off Box contains an arrangement of enclosure, circuit breaker, monitoring device (optional),
rotary handle (load isolator) and safety interlocks that provide a unique set of safety features that allow
installing or removing the Tap-Off Boxes while the Liebert® MBX Busway System is energized.
The proprietary, spring-loaded mechanical interlock ensures:
• The Tap-Off Box can be inserted in the busway system only with the rotary handle (load isolator) in
the Off position.
• The Tap-Off Box is correctly located and fixed to the busway track frame.
• The tap-off conductors can be inserted onto the busway track while ensuring that no conductors
are exposed to the installer.
The Liebert MBX housing, earth strip and mechanical housing ensure that the Tap-Off Box cannot be
inserted the wrong way with reverse polarity.
The rotary handle (load isolator) of the Tap-Off Box has a further positive engagement tab that must be
operated to allow the rotary handle to be operated.
The Tap-Off Box is fully grounded/earthed before any phase connections are made and the
earth/ground remains intact after any phase connections are broken in the event of Tap-Off Box
installation/withdrawal. This safety features ensures electrical safety throughout the operation.
To install the Tap-Off Box:
NOTE: Remove the Tap-Off Box from its packaging and ensure no damage is visible to the device.
1. Align the Tap-Off Box with the housing and visually line up the earth/ground strip and the interlock
channel on the casing. Insert the ground strip.
2. Pull back the spring-loaded interlock and rotate the box into position, then release the spring-
loaded interlock when parallel with the busway track.
3. Verify that the ground strip has rotated within the interlock channel and the spring-loaded
interlock has released. Verify that the Tap-Off Box is secured in place. See Tap-Off Box Installation
on page 16.
NOTE: Ensure that the box is fully supported during this procedure.
CAUTION: Ensure the spring-loaded interlock is seated properly before engaging the rotary
handle.
4. Engage the contacts by rotating the rotary handle 90 degrees. The handle has a safety feature built
in and the engagement tab must be pushed in before the rotary handle can be turned.
5. (Optional) If a Tap-Off Box has a factory-installed monitoring option, it will have two ethernet ports
on the side of the enclosure (see supplement SL-70526 for detailed monitoring connection
information). Using an RJ-45 ethernet cable, connect one end to the power feed box; daisy-chain
the other between Tap-Off Boxes, as required.
6. Connect one RJ-45 cable from the network to the Power Feed Box for monitoring of the Tap-Off
Boxes. See Optional Ethernet Connection on page 16
7. As an additional safety feature, you can padlock the handle in the Off position. This allows you to
work freely within the cabinet without electrical hazard risk. See Padlock Diagram on page 16.
2 Installation
15