Electrical power cable cabinet penetrations.

Hello marcot

It may well be that the installation did not use plain steel for the penetration plate.

If plain steel was used, there would normally be a longitudinal slot, the width of even 0.5mm running across the hole centres for the cables, to minimise eddy currents in the plate.

Here in similar situations, I have seen insulating plates used, with the earthing bushes directly fitted on each of the cables, which gets around the problem.

But if that plate penetration is plain steel, without the slotting between, there would be heavy circulating currents in it, not a good practice.

Kind Regards....

I agree with you about the circulating currents. The holes were in plain steel with a bushing per cable. No slots or glan plates were used. I would have liked to measure the cabinet temperature at full load but they were operating at low capacity. My IR thermometer didn't record much of a delta T. I didn't see any discoloration of the paint so the temperature rise should be below 100C. When I asked their electrical engineer about it, he told me that they always do it that way.

Hello again marcot

It may well be that the Electrical Engineer has used steel for the Gland plates, and has weighed up the flameproofing requirements of the cabinet using a full steel enclosure, against the heating losses incurred by the circulating currents.

As an alternative, the Gland plate may be made of heavy brass, aluminium alloy ("Birmabright" or similar alloy suitable for maritime conditions).

If non-magnetic materials are used for the Gland plate, the circulating currents are minimised, being localised in the immediate vicinity of each phase.

Kind Regards....

Dear friend,

The Cable size is designed separately and the cut out size depends on the GA of the Panel which we are going to use. For ex. if we have as Panel of size 800 x 450 mm then we can have a 3Cx 630 sq.mmcable to transmit 11 kV Voltage considering the cable dia . of around 57 mm .

For higher size which is used in the case of Transformer of 220/66 kV volatge class a 2 runs x of 1000 sq.m cable can be used per phase and a separate cable for neutral bushing which will not be terminated inside the cable box. The cable box normallly oil filled type and for this kV rating. A separate cut out will be there for each phase cable. The cable box must be designed in such a way to accomdate all the three phase cables. This practically applied in many locations.

Regards,

N.Suresh

Hello

I have answered your Post/comments,

Generally best to use the Cable Maker of your particular cable, but try:

http://relemaccables.com/

If you are still needing help, reply with

Kind Regards....