2-46
AFP-400 Installation
PN
50253
:
A2 03/12/96
Wire Requirements for a Two-Wire SLC Circuit
The total DC resistance from panel to branch end cannot exceed
40 ohms. Measure DC resistance as follows:
1) Short the termination point of one branch at a time. Measure the DC
resistance
from the beginning of the loop to the end of that particu-
lar branch.
2) Repeat this procedure for all remaining branches in the SLC loop.
For detailed wiring require-
ments, refer to Appendix B.
Communications Loop Out
Branch
The total length of wire (12 AWG) in a two-wire loop cannot exceed
10,000 feet. Find the total length of wire in the loop by summing the
wire lengths on each loop. The following wiring diagram shows how to
find the total length wire in a typical SLC loop.
1
2
3
4
5
6
TB5
no connection
Loop Out
(Branch A)
+
(Branch B)
+
(Branch C)
+
(Branch D)
+
(Branch E)
=
10,000 feet or less
Wiring a Two-wire SLC Loop
Loop Resistance
Finding the Total Length of Wire in a Two-Wire SLC Circuit
Branch D
Branch C
Branch E
Branch B
Branch A
