2. Installation
10
Detecting Gas Saving Lives
English
2.4.1 To fit IRmax to an auxiliary junction box:
a. Carefully remove the outer section of the spigot gland (item 8 in Diagram 3 on
b. Screw the narrow end of the spigot gland into the auxiliary junction box.
c. Raise the
IRmax
to the auxiliary junction box and pass the wires through the
assembly and into the auxiliary junction box. Secure the
IRmax
by screwing the
collar tightly to the cable gland. Tighten grub screw.
d. The main body of the
IRmax
can be swivelled horizontally at any angle, provided
it is mechanically secure, does not interfere with other equipment and is
accessible for maintenance.
e. Refer to Section 2.6 for instructions on wiring. See also Diagram 4 on page 7.
2.5 Cabling requirement
Cabling to
IRmax
must be in accordance with the recognised standards of the appropriate
authority in the country concerned and meet the electrical requirements of the
IRmax
.
Crowcon
recommends the use of steel wire armoured (SWA) cable and suitable explosion
proof glands must be used. Alternative cabling techniques, such as steel conduit, may be
acceptable provided appropriate standards are met.
The maximum recommended cable length is 3.4 km (see Table 1).
IRmax
requires a dc supply of 12-30Vdc. Ensure there is a minimum of 12V at the
IRmax
from the control panel, taking into account the voltage drop due to cable resistance at a
peak current of 0.1A.
A 1.5mm
2
cable will typically allow cable runs up to 3.0km. Table 1 below shows the
maximum cable distances for typical cable parameters.
C.S.A.
Resistance
Max. Distance
>20 V
Max. Distance
18 to 20 V
mm
2
(Ohms per km)
(km)
(km)
1.0
18.4
2.2
1.6
1.5
13.0
3.0
2.3
2.5
11.5
3.4
2.6
Table 1: Maximum cable distances for typical cables
