Alstom MiCOM P546 - 6. RELAY WIRING

P54x/EN IN/La4 Installation
(IN) 15-8 MiCOM P543, P544, P545 & P546
IN
6. RELAY WIRING
This section serves as a guide to selecting the appropriate cable and connector type for
each terminal on the MiCOM relay.
6.1 Medium and heavy duty terminal block connections
Key:
Heavy duty terminal block: CT and VT circuits, terminals with “D” prefix
Medium duty: All other terminal blocks (grey color)
Loose relays are supplied with sufficient M4 screws for making connections to the rear
mounted terminal blocks using ring terminals, with a recommended maximum of two ring
terminals per relay terminal.
If required, ALSTOM Grid can supply M4 90° crimp ring terminals in three different sizes
depending on wire size (see table below). Each type is available in bags of 100.
Part number Wire size Insulation color
ZB9124 901
0.25 - 1.65 mm
2
(22 - 16 AWG)
Red
ZB9124 900
1.04 - 2.63 mm
2
(16 - 14 AWG)
Blue
ZB9124 904
2.53 - 6.64 mm
2
(12 - 10 AWG)
Un-insulated*
*To maintain the terminal block insulation requirements for safety, an insulating sleeve
should be fitted over the ring terminal after crimping.
The following minimum wire sizes are recommended:
Current Transformers 2.5 mm
2
Auxiliary Supply, Vx 1.5 mm
2
EIA(RS)485 Port See separate section
Other Circuits 1.0 mm
2
Due to the limitations of the ring terminal, the maximum wire size that can be used for any of
the medium or heavy duty terminals is 6.0 mm
2
using ring terminals that are not
pre-insulated. Where it required to only use pre-insulated ring terminals, the maximum wire
size that can be used is reduced to 2.63 mm
2
per ring terminal. If a larger wire size is
required, two wires should be used in parallel, each terminated in a separate ring terminal at
the relay.
The wire used for all connections to the medium and heavy duty terminal blocks, except the
EIA(RS)485 port, should have a minimum voltage rating of 300 Vrms.
It is recommended that the auxiliary supply wiring should be protected by a 16 A high rupture
capacity (HRC) fuse of type NIT or TIA. For safety reasons, current transformer circuits
must never be fused. Other circuits should be appropriately fused to protect the wire used.
Note: The high-break contacts optionally fitted in P54x relays are polarity
sensitive. External wiring must respect the polarity requirements
which are shown on the external connection diagram to ensure correct
operation.