Earthing - ABB 07CR41 Operating Manual

4.1.4

Earthing

3
•
Basic earthing principles
The earth and mains wires should be connected in star.
All AC 31 components of a cabinet should be connected to the same earth.
If the remote units are located outside the cabinet, they should be connected to the nearest
earth.
The 40 and 50 series basic units are fitted with an earth plate on the DIN rail mounting system.
If the basic unit is screwed directly to a metal plate, the screw located at the top left of the
basic unit (as seen from the front) ensures an electrical connection to the earth via this earth
plate.
This earthing ensures protection against electromagnetic disturbances.
The safety earthing cable (on terminal block) should be connected to the cabinet chassis (PE-
.
terminal)
•
Earthing principles for several cabinets
If the cabinets are close to each other, the different earths should possibly be connected
together using a cable with a cross section of at least 16 mm² (see Figure 6, page 4–3).
The noise generating devices (actuators, motors, etc.) should not be earthed in between two
cabinets. The earthing should be done near to the element causing the most disturbance (see
Figure 6, page 4–3).
We recommend you connect the bus shielding directly to the earth, as shown in the assembly
diagram (see Figure 5, page 4–3.)
Installation 4 – 4
Advant Controller AC 31 / Issued: 08.99