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Procedure:
To connect one or more external battery cabinets to a UPS, perform the following steps:
1) Verify that the breaker inside each battery cabinet is turned off. Verify that the UPS is off, and
verify that all battery breakers, as well as the AC breaker, on the front of the UPS are off. No
power must be present during the installation procedure. The qualified electrician should select
wire and conduit sized to meet the battery currents shown in Table 7 and meeting the wire
range shown in Table 8.
Table 8 External Battery Wire Size and Torque Requirements
UPS Size
Tool
Allowable wire size (Cu) Torque (in-lbs.) Torque (N-m)
6 AWG –4 AWG
45
5.0
3 AWG
50
5.6
10-15 KVA
Flat Blade
Screwdriver
2 AWG -1/0 AWG
60
6.8
6 AWG –1 AWG
120
14
20-30 KVA
5/16” Allen wrench
1/0 AWG – 350 kcmil
275
31
50 KVA
3/8” Allen wrench
3/0 AWG –500 kcmil
300
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2) The qualified electrician will find pilot holes above the External Battery Breaker on the top of the
UPS cabinet and above the breaker on the top of the External Battery Cabinet, unless the
customer requests otherwise. The electrician can use the appropriate punch to prepare both
cabinets for the type of conduit and connector that are going to be used on-site. Drilling or filing
is not recommended, as the metal particles could interfere with the internal electrical/electronic
equipment.
3) The wires should be cut to the appropriate length, and one wire should be marked at both ends
with
white tape
to indicate this is the (+) wire. The other wire can be left black.
4) Once the wires are marked, they can be fed through the conduit from one cabinet to the other.
5) The wire marked
white
should be inserted on the left side of the breaker (from the top) which is
indicated to be "+". The
unmarked
wire should be inserted on the right side of the breaker (from
the top) which is indicated to be "-". According to Mesta convention the left side of the breaker
will be (+) and the right side (-).
6) Make sure that the wire is stripped properly and that sufficient wire is inserted in the breaker lug
for a solid mechanical and electrical connection. Refer to Table 8 for tightening torque and
required tool. A copper lug marked “GND” is supplied on the upper right side of the UPS for the
purpose of grounding the cabinet to earth ground. This lug will accommodate wiring between 8
and 2 AWG for units up to and including 30 KVA, and wiring between 8 and 1/0 AWG for
systems above 30 KVA. A wire size that meets local electrical codes must be selected and may
be routed with the AC supply wiring to the service distribution panel earth ground. Alternatively,
a hole can be drilled and tapped on the backside of the cabinet frame (not the panel), near the
bottom to provide an external chassis ground. Care should be taken so that metal particles
produced by such operation are not allowed to come in contact with any internal electrical
components.
7) Copper lugs marked “GND” are supplied on the upper right side of the Battery cabinet and the
upper left side of the UPS cabinet for the purpose of grounding the Battery cabinet to earth
ground via the UPS. This lug will accommodate wiring between 8 and 2 AWG for units up to and
including 30 KVA, and wiring between 8 and 1/0 AWG for systems above 30 KVA. A wire size
that meets local electrical codes must be selected and may be routed with the Battery wiring to
the UPS. Alternatively, a hole can be drilled and tapped on the backside of the Battery cabinet
frame (not the panel), near the bottom to provide an external chassis ground. Care should be
taken so that metal particles produced by such operation are not allowed to come in contact
with any internal electrical components.