Chapter 3 ________________________________________________________________  Installation 
 
VAISALA ________________________________________________________________________ 27 
Table 6  AC (Mains) Cable Selection 
from Voltage 
Section Area 
Gauge 
Armored Cable 
 
NOTE 
Cables with diameters more than 15
 mm require a separate junction box, 
such as Termbox1200, available from Vaisala.
 
 
Communication Cable 
The customer must provide cables and conduits. The cables used for the 
transmission of digital and low-level analogue signals should be of the 
following kind: All field cables should be armored, suitable for 
underground use, and led to the equipment through conduits. Unless the 
cables are armored, they have to be led through pipes. The signal cable 
shields should be grounded at both ends. 
For modem and RS signal cable use a screened 2 x 0.22 mm
2
 (AWG 24, 
conductor diameter 0.61 mm) twisted pair signal cable with a shield and 
minimum external diameter of 8 mm. If the modem line length exceeds 
50 km, consult Vaisala. 
If RS-485 connections are used, pay special attention to the quality of the 
cable. The shield should be continuous, in other words, also connected to 
the distribution frames. 
For more information, see section Communication Options on page 48. 
NOTE 
Cables with diameters more than 15
 mm require a separate junction box, 
such as Termbox1200, available fr
om Vaisala.