Product Guide
VESDA ECO Detector by Xtralis
14
Installation
Power Supply Connection
When connecting the power supply to the ECO device the system designer and
installer must take consideration of the voltage drops over long lengths of cable.
The resistance, and therefore voltage drop, along the line is a factor of the cable
length and the cross sectional area of the wire.
When considering the issue of voltage drop, the designer and installer must ensure
that the supply voltage provided to each unit along the line is within specification. If
cable with too high resistance is used, the voltage at the last device on the line will
be too small. However, if the installer merely increases the voltage from the supply
it could lead to the first unit in the line being supplied with a voltage in excess of
specification.
Below is a table a representative values for resistance of different cable core ratings
however it is only intended as a guide for cable size selection.
AWG
CSA
mm
2
Maximum
current (A)
Ω
/ft
@77°F
24
0.205
0.410
0.03490
22
0.326
0.651
0.02198
-
0.5
1.0
0.01073
20
0.518
1.035
0.01036
0.75
1.5
0.00930
18
0.823
1.646
0.00652
-
1.0
2.0
0.00539
-
1.25
2.5
0.00430
16
1.309
2.618
0.00408
Table 1 Current Capacity & Resistance of Stranded Copper Wires
Wherever and whenever possible the user should refer to the
manufacturers’ specification for the cable to be used in the installation.
Use these figures rather than those given above when makin
calculations required to determine the suitability of the cable as detailed
in the rest of this manual.
VESDA ECO Detector by Xtralis
17898_05
stem designer and
installer must take consideration of the voltage drops over long lengths of cable.
The resistance, and therefore voltage drop, along the line is a factor of the cable
issue of voltage drop, the designer and installer must ensure
that the supply voltage provided to each unit along the line is within specification. If
too high resistance is used, the voltage at the last device on the line will
However, if the installer merely increases the voltage from the supply
a voltage in excess of its
of different cable core ratings
Ω
/m
@25°C
0.1145
0.072
0.035
0.034
0.030
0.021
0.018
0.014
0.013
Current Capacity & Resistance of Stranded Copper Wires
Wherever and whenever possible the user should refer to the
specification for the cable to be used in the installation.
Use these figures rather than those given above when making the
calculations required to determine the suitability of the cable as detailed
