Emerson Edition 4 Water Heater User Manual


 
11-1
Rosemount Tank Radar REX
Chapter 11 Electrical Installation of the
Installation Manual
308014EN, Edition 4
May 2013
11. Electrical Installation of the REX Gauges
Warning! Isolate and terminate ends of unused wires. The intrinsic safety may be
jeopardized if any cable ends are hanging loose. Use certified battery
operated instruments only. Use Rosemount Tank Gauging original spare
parts only.
Note! See the instructions in the electrical installation drawings for further
information. See list of drawings in chapter 12.
11.1 Cabling for Power Supply
Cables used for the power supply connection must be suitable for the
supply voltage in question and also approved for use in hazardous area
where it is applicable. In the USA, for example, explosion proof conduits
must be used in the vicinity of the tank. Appropriate cross sectional area
of wires must be used in order to prevent a too high voltage drop to the
connected device.
Table 11-1 and Table 11-2 show examples of typical voltage drops for
various cable lengths, wire areas and supply voltages at the maximum
power consumption of 80 W (30 W for 24 VDC).
The presented voltage drops should only be treated as guidelines since
actual values depend on the particular cable type that is used for the
installation. The figures shaded in grey indicate combinations of lengths
and areas that might result in too high voltage drops.
Note that the REX gauge can use a wider range of supply voltages than
shown in Tables 11-1 and 11-2:
100-240 VAC,
34-70 VAC,
48-99 VDC,
20-28 VDC.