Warning:For safety reasons always fit an insulating sleeve over the ring terminal.4.2 POWER SUPPLY CONNECTIONSThese should be wired with 1.5 mm PVC insulated multi-stranded copper wire terminated with M4 ringterminals.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 rupturecapacity (HRC) type NIT or TIA fuse.4.3 EARTH CONNNECTIONEvery device must be connected to the cubicle earthing bar using the M4 earth terminal.Use a wire size of at least 2.5 mm2 terminated with a ring terminal.Due to the physical limitations of the ring terminal, the maximum wire size you can use is 6.0 mm2 using ringterminals that are not pre-insulated. If using pre insulated ring terminals, the maximum wire size is reducedto 2.63 mm2 per ring terminal. If you need a greater cross-sectional area, use two wires in parallel, eachterminated 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 theproduct, 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 tinnedring terminals.4.4 CURRENT TRANSFORMERSCurrent transformers would generally be wired with 2.5 mm2 PVC insulated multi-stranded copper wireterminated with M4 ring terminals.Due to the physical limitations of the ring terminal, the maximum wire size you can use is 6.0 mm2 using ringterminals that are not pre-insulated. If using pre insulated ring terminals, the maximum wire size is reducedto 2.63 mm2 per ring terminal. If you need a greater cross-sectional area, use two wires in parallel, eachterminated 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 areshorted before the CT contacts are broken.MiCOM P747 Chapter 13 - InstallationP747-TM-EN-1 337
