Areva MiCOM P441, Technical Manual

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Installation P44x/EN IN/E33
MiCOM P441/P442 & P444 Page 5/10
4.1 Rack mounting
MiCOM relays may be rack mounted using single tier rack frames (our part number FX0021
001), as illustrated in figure 2. These frames have been designed to have dimensions in
accordance with IEC60297 and are supplied pre-assembled ready to use. On a standard
483mm (19”) rack system this enables combinations of widths of case up to a total
equivalent of size 80TE to be mounted side by side.
P545 and P546 relays in 80TE cases are also available as direct 19” rack mounting ordering
variants, having mounted flanges similar to those shown in figure 2.
The two horizontal rails of the rack frame have holes drilled at approximately 26mm intervals
and the relays are attached via their mounting flanges using M4 Taptite self-tapping screws
with captive 3mm thick washers (also known as a SEMS unit). These fastenings are
available in packs of 5 (our part number ZA0005 104).
NOTE: Conventional self-tapping screws, including those supplied for
mounting MIDOS relays, have marginally larger heads which can
damage the front cover moulding if used.
Once the tier is complete, the frames are fastened into the racks using mounting angles at
each end of the tier.
P0147XXa
FIGURE 2 - RACK MOUNTING OF RELAYS
Relays can be mechanically grouped into single tier (4U) or multi-tier arrangements by
means of the rack frame. This enables schemes using products from the MiCOM and
MiDOS product ranges to be pre-wired together prior to mounting.
Where the case size summation is less than 80TE on any tier, or space is to be left for
installation of future relays, blanking plates may be used. These plates can also be used to
mount ancillary components. Table 1 shows the sizes that can be ordered.