11-5
Rosemount Tank Radar REX
Chapter 11 Electrical Installation of the
Installation Manual
308014EN, Edition 4
May 2013
The RTG 3900 version without Integrated Junction Box is delivered with
a 2 m long cable. If the distance between the transmitter and connected
devices is longer than 2 meters, a junction box must be used to connect
an extension cable. The extension cable must not be longer than 50 m.
An external junction box can either be customer supplied or supplied by
Emerson Process Management/Rosemount Tank Gauging as an option.
Note! For safety reasons unused wires must be properly insulated and
terminated.
A flexible protective hose for the wires is delivered with the transmitter. If
a DAU is used, it is very important that a continuous metal shield covers
the wires between the Transmitter Head and the DAU to avoid
electromagnetic interference between cables. If an extension cable is
used, both the cable and the junction box must provide good shielding.
Note! Select external fuse rating with respect to area temperature classification
(T1-T6) and maximum expected ambient temperature to prevent
overheating of the internal wiring in the JBI junction box (0.5 mm²).
Example: Max. allowed (fault) current in a T4 installation with 70°C
ambient is 7.5 A acc. to the lead seal component certificate PTB 97
ATEX 1047 U.