supply setup

[jim23]

hi, not really a DIY question but here goes.....

on an industrial build where we are currently doing some work i came across a setup ive not seen before.

the main switchroom is right next to a sub station. out of the substation room came 2 big cables (swa 4x300 by the looks of it). These supply'd mains switches for 2 different parts of the factory.

almost like 2 seperate supplies. The meter panel is in the main switchroom on the wall backing onto the substation room but has only one swa cable attached to it (probably 35mm only if 4 core).this cable runs into the substation room by the looks of it. on the meter it says 3x800A supply.

anybody shed any light?

 

[breezer]

so whats the question?

if you are wondering why the meter cable is so small thats easy.

unlike domestic meaters industrial meters work by the current flowing through a torodial transformer. the incoming cores pass through the transformer one for each phase.

The voltage these transformers produce operate the the meter, so no big cable required

 

[Lectrician]

Sounds like HV metering to me. The supply must be purchased as HV, and then you are responsible (and own) the sub.......or sub the work back to the DNO.

The 35mm 4 core you say will actually be a multicore 2.5. This connects to the 3 Current Transformers, and the associated voltage connection points in the sub (depending on setup, sub make etc).