User's Manual

BTS Power Cabling
68P64115A19–4
Mar 2003
1X SC 4812T-MC BTS Hardware Installation - Software Release R2.16.1.x
CONTROLLED INTRODUCTION
2-44
In the + 27 V configuration the power supply input “+” and “–”
terminals are isolated from the BTS chassis ground. In order to control
the inductance at the BTS power input due to the feed cables, the
positive and negative cables (feed and return) must be bound together at
intervals of 1 meter or less (see Figure 2-20).
Meeting these limits will ensure a voltage drop of less than 2% due to
cable resistance, and will control the source impedance to ensure
stability of the power supply.
Table 2-35: Maximum Cable Length
Number of
Carriers
Number of
Feeds
Cable Type
Maximum
Length in
meters
1–2 1 AWG 2/0 22
1–2 1 AWG 3/0 28*
1–2 1 AWG 4/0 28*
3–4 1 AWG 2/0 12.2
3–4 1 AWG 3/0 15.4
3–4 1 AWG 4/0 19.4
3–4 2 AWG 2/0 22
3–4 2 AWG 3/0 28
3–4 2 AWG 4/0 28*
* Limited by inductance rather than voltage drop.
Figure 2-20: Length and Tie-Down Requirements for BTS Power Cables
ti-CDMA-WP-00077-v02–ildoc–ftw REF.
1
2
POWER SOURCE
BREAKER 1
TIE ALL CABLES
AT 1 METER INTERVALS
See Table 2-35
for cable length
BREAKER 2
GROUND
BTS
2