Specifications

Calculations C
SHM80001
SAFETY HI-TECH
Quaestor-SZU Releasing Fire Control Panel - Installation and Operation Manual
Revision E03.04
114 of 155
The figure below illustrates the maximum wire length example of the SRV circuit:
Figure C-3
Maximum Wire Length Example
5 Identify the resistance-per-foot of the wire gage used in the circuit (R
wiremax
) when using 18 AWG copper.
The table below describes the resistance-per-foot of an 18 AWG solid-copper-wire:
6 The calculation for maximum wire length of this SRV circuit is:
L
max
= 1/2 ( V
drop
/ I
max
) / R
wire
where,
= 1/2 [ ( 4.1 VDC / 0.584 A ) / ( 0.006385 Ohms / FT ) ]
Gage Resistance / 1000Ft @ 68F
R
wire
18 AWG 6.385 Ohms
0.006385 Ohms / FT
16 AWG 4.016 Ohms
0.004016 Ohms / FT
14 AWG 2.525 Ohms
0.002525 Ohms / FT
R
wire
= 0.006385 Ohms / FT
L
max
= 550 FT
+
-
+
-
EXTING.
L
max
= 550 FT
V
outmin
V
opmin
Imax
EOL Diode 1N4004,
band end to ( + )
V
outmin
is measured at the EXTING. terminals.
V
opmin
is measured at the SRV terminals.
SRV