4188-1075 issue 3_Part 2_08/14
7
Loop Loading
Loop length and quantities for Standard mode with non VAD devices
Use either Table 2 or Table 3 to determine the maximum number of devices on a loop and loop cable length possible for lumped
alarm load. The examples 1 and 2 below show how to use the tables to determine loading and loop cable length.
Table 2 Lumped load using 1.5mm² loop cable
Assuming S-Quad with older sounder including strobe and S-Cube Mark 1/2 devices, ie non compliant Part 23 devices.
A
Total
Alarm
Current
Loop cable length in Km including spurs using 1.5mm² cable
B
C
Maximum allowed devices of any type on a loop for a
Lumped alarm load
only.
blank cell = 200 devices
n/a = not applicable (condition not allowed)
0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2.0
225 mA
250 mA
190 160 130
275 mA
190 150 130 100 70
300 mA
170 130 100 70 n/a n/a
325 mA
180 150 120 90 n/a n/a n/a n/a
350 mA
170 140 110 70 n/a n/a n/a n/a n/a
375 mA
160 130 100 70 n/a n/a n/a n/a n/a n/a
400 mA
170 140 110 70 n/a n/a n/a n/a n/a n/a n/a
Table 3 Lumped load using 2.5mm² loop cable
Assuming S-Quad with sounder including strobe and S-Cube Mk 1/2 devices, ie non compliant Part 23 devices.
A
Total
Alarm
Current
Loop cable length in Km including spurs using 2.5mm² cable
B
C
Maximum allowed devices of any type
on a loop for a
Lumped alarm load
only.
blank cell = 200 devices
n/a = not applicable (condition not
allowed)
0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2.0 2.1 2.2 2.3 2.4 2.5
200 mA
275 mA
300 mA
190 170 150
325 mA
180 170 150 120 100
350 mA
180 150 120 110 100 80 60
375 mA
190 170 150 120 100 80 60 n/a n/a
400 mA
190 170 150 130 110 90 70 n/a n/a n/a n/a
Example 1
Devices allowed on a known loop cable length for Lumped alarm load
If the loop cable length is known then you can determine the maximum number of devices that can be connected to a loop where
there is lumped alarm devices.
a. First calculate the
total alarm current
value
A
, use
Table 1
.
b. Use the calculated
total alarm current
A
and the known loop cable length
B
to look up in
Table 2
or
3
the maximum number
of devices
C
that can be connected to the loop.
For example if the
total alarm current
A
is 350mA when using 1.5mm² loop cable that is
B
1.5Km in length, then
Table 2
tells
you for
lumped alarm devices
the maximum number of devices allowed on the loop must be limited to
C
70
devices.
Example 2
Loop cable length allowed for known Lumped alarm device load
If the number of devices on a loop is known then you can determine the maximum cable length that can be used on the loop circuit.
a. First calculate the
total alarm current
value
A
, use
Table 1.
b. Use the
total alarm current
A
and the known number of devices on the loop to look up in
Table 2
or
3
and work out the
maximum length of loop cable allowed
B
for the connection lumped alarm devices.
For example if the
total alarm current
A
is 225mA and if 200 devices
C
are required on the loop, then
Table 2
tells you the
maximum loop cable length
B
can be 2Km for lumped alarm load, when using 1.5mm² loop cable. However Table 2 tells you if
2.5mm² loop cable is used then the cable length can be up to 2.5Km.
