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MOTOR TERMINAL BOX Cable Connection Arrangement

MOTOR TERMINAL BOX Cable Connection Arrangement

MOTOR TERMINAL BOX Cable Connection Arrangement

hello, i would like to ask about wiring methodology.
i have a motor terminal box, with 2 holes, 2xM63 aparently i am using a single core cable. and by using trefoil cable arrangement, it won't fit in one of the M63 existing hole entry.
so our customer inform that use the 2 holes x M63 by doing L1, L2 on the 1st hole and L3, G on the 2nd hole.

I just want to ask, is there an effect for Low Voltage Motor Wiring installation?
What's the disadvantage.
If not, is this installation acceptable, or is there a code stating it's not's allowed
Thanks a lot in advance

RE: MOTOR TERMINAL BOX Cable Connection Arrangement

There are two issues here:
1.- Canadian Code; 12-904 Conductors in raceways
(1) Where conductors are placed in metal raceways, all conductors of a circuit shall be contained in the same
In the Canadian code there is a warning on magnetic encirclement of single conductors.
2.- A single conductor will cause heating of any ferrous material which encircles it. The heating will be from both eddy currents and from hysteresis. The same heating will occur when two conductors out of a three conductor circuit are encircled magnetically.
This effect may be mitigated by using non-ferrous connectors (die cast) and by entering through an aluminum plate or insulating (micarta) plate.
Another mitigation method that is economical in terms of both material and labour is to join the holes in the junction box with a hacksaw cut. This makes the entry effectively one hole magnetically.

Ohm's law
Not just a good idea;
It's the LAW!

RE: MOTOR TERMINAL BOX Cable Connection Arrangement

In short, it's a poor installation. Acceptable or not, it depends on your particular code and if you are referring to equipment wiring or installation wiring.

Where I am, if it is installation wiring, it would not be for two reasons, the earth conductor is not enclosed with the circuit and the circuit conductors are in different conduits.

Sounds like you should use two parallel sets of cables with smaller size that do each fit within the m63 termination or modify the terminal box so it is suitable.

RE: MOTOR TERMINAL BOX Cable Connection Arrangement

It seems a bit strange to me that a motor terminal box, isn't manufactured to fit the dimension for cables and such that it needs to meet the revilements. ponder

An example of a cable outer diameter cable 53 mm up to 54 mm for some.

And this is a M63 cable gland it takes a cable diameter 42-54 mm

But I also see in the drawing that it says 2'1/2 which would give you 50-63 mm with this one

Best Regards A

“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

RE: MOTOR TERMINAL BOX Cable Connection Arrangement

Yes apparently they use single core and not multicore for the motor cables

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