Warning:
For safety reasons always fit an insulating sleeve over the ring terminal.
4.2 POWER SUPPLY CONNECTIONS
These should be wired with 1.5 mm PVC insulated multi-stranded copper wire terminated with M4 ring
terminals.
The wire should have a minimum voltage rating of 300
V RMS.
Caution:
Protect the auxiliary power supply wiring with a maximum 16 A high rupture
capacity (HRC) type NIT or TIA fuse.
4.3 EARTH CONNNECTION
Every device must be connected to the cubicle earthing bar using the M4 earth terminal.
Use a wire size of at least 2.5 mm
2
terminated with a ring terminal.
Due to the physical limitations of the ring terminal, the maximum wire size you can use is 6.0 mm
2
using ring
terminals that are not pre-insulated. If using pre insulated ring terminals, the maximum wire size is reduced
to 2.63 mm
2
per ring terminal. If you need a greater cross-sectional area, use two wires in parallel, each
terminated in a separate ring terminal.
The wire should have a minimum voltage rating of 300 V RMS.
Note:
To prevent any possibility of electrolytic action between brass or copper ground conductors and the rear panel of the
product, precautions should be taken to isolate them from one another. This could be achieved in several ways,
including placing a nickel-plated or insulating washer between the conductor and the product case, or using tinned
ring terminals.
4.4 CURRENT TRANSFORMERS
Current transformers would generally be wired with 2.5 mm
2
PVC insulated multi-stranded copper wire
terminated with M4 ring terminals.
Due to the physical limitations of the ring terminal, the maximum wire size you can use is 6.0 mm
2
using ring
terminals that are not pre-insulated. If using pre insulated ring terminals, the maximum wire size is reduced
to 2.63 mm
2
per ring terminal. If you need a greater cross-sectional area, use two wires in parallel, each
terminated in a separate ring terminal.
The wire should have a minimum voltage rating of 300 V RMS.
Caution:
Current transformer circuits must never be fused.
Note:
If there are CTs present, spring-loaded shorting contacts ensure that the terminals into which the CTs connect are
shorted before the CT contacts are broken.
MiCOM P747 Chapter 13 - Installation
P747-TM-EN-1 337
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