Alpha Technologies CXPS 48-2T 48V Pos Gnd - Manual (Page 26)

Argus Technologies Ltd. 053-393-C0 Rev A WC
Printed in Canada. © 2007 Argus Technologies Ltd. ARGUS and CORDEX are trademarks of Argus Technologies Ltd. All Rights Reserved. Page 16 of 32
5 Wiring
This chapter provides cabling details and notes on cable sizing for DC applications with respect to the product.
WARNING
Ensure that power is removed by turning off rectifiers and removing battery line fuse or
connection before attempting work on the wiring connections. Use a voltmeter to verify the
absence of voltage. Clearly mark the correct polarity of the battery leads before commencing work
on DC connections.
Refer to the previous (Installation) chapter for safety precautions and tools required.
5.1 Grounding
The isolated power system battery return bus (BRB) should be connected to the building master ground bus
(MGB) or floor ground bus (FGB) in a larger building. This acts as a system reference and as a low impedance
path to ground for surges, transients, noise, etc. The MGB or FGB should have a direct low impedance path to
the building grounding system. The cable from the power system to the MGB or FGB should be sized to provide
sufficient ampacity to clear the largest fuse or breaker on the power system, excluding the battery protection fuse
or circuit breaker. This is the minimum requirement; other factors including length of cable and special grounding
requirements of the load should also be factored in. The insulated cable should be equipped with two-hole crimp
type lugs and should not have any tight bends or kinks.
Power System Ampacity Ground Reference Conductor Size
< 30A #10
30 – 100A #6-2
100 – 400A 0000
400 – 800A 350 MCM
> 800A 750 MCM
Table B–Typical ground reference conductor selection
The power system frame must also be connected to the MGB or FGB. This is done for personnel safety and to
meet many Telco grounding requirements. Each bay should have its own frame or site ground connection (see
Figure 6). Refer also to the Customer Connections drawing at the rear of the manual.
5.2 AC Feeder Protection/Sizing
To maximize system reliability, each power module should be fed from a dedicated protection feeder breaker
located at the AC distribution panel. The feeder breaker can also act as the disconnect device for the connected
module. Refer to the specifications at the front of this manual for Argus recommendations.
5.3 AC Input Connections
CAUTION: AC input wires should be routed in flexible or rigid conduit as far away as possible
from the DC power wires to minimize EMI disturbances.
Ensure all modules are removed from the shelf and refer to the Customer Connections drawing at the rear of the
manual for AC terminal block location.
Remove the covers (2 places) from the rear of the shelf to expose the AC input terminal blocks, L1 and L2 for
each rectifier. Each terminal pair relates to an individual power module as marked.
WARNING
Use care when removing or replacing the covers for the AC input connections. Never assume that
an electrical connection or conductor is not energized.
The wireway is designed for two customer-supplied 1” conduit fittings for AC supply located one on each side of
the shelf. Attach the conduit retainers to the wireway hole(s) and route the AC cables through. Secure the wires to
the AC input and chassis ground terminals as required. Tighten the cable connector to the AC cable (conduit
similar).
Replace rear cover(s) once all connections have been completed.