Large cable protective device and enclosures

[2piesFC]

Hi, thanks for reading this.
Ive been asked to look at a job where the DNO connection (single phase 80A TT) is a long run to the final circuits. Small feeder box has been installed and the volt drop dictates 95mm cables are needed to take to another feederbox where the feeds into the building will be taken. Im trying to find some good quality switch gear that will take this size cables but is also not too large. Wondering what people are using for similar circumstances

 

[davesparks]

Firstly I'd run a pair of smaller cables in parallel to make life easier, you might get that down to 2x35mm depending on exact distance.

Secondly big cables and small switchgear don't go together, you are going to need something fairly big.
To make the final connections to the switchgear I would terminate the large cables in an enclosure and joint them to smaller cables with bolted type din rail connectors to make the final connection into smaller switchgear.

 

[2piesFC]

Firstly I'd run a pair of smaller cables in parallel to make life easier, you might get that down to 2x35mm depending on exact distance.

Secondly big cables and small switchgear don't go together, you are going to need something fairly big.
To make the final connections to the switchgear I would terminate the large cables in an enclosure and joint them to smaller cables with bolted type din rail connectors to make the final connection into smaller switchgear.

Hi, thanks for the reply.
The run is 100m to a proposed feeder box, then a further 25m to a house and 50m to a small workshop.

What switchgear would be best suited to using a parallel feed? I was goijg to TT this at each connection point with the runs being so long

 

[davesparks]

What switchgear would be best suited to using a parallel feed?

Whatever brand of switchgear you normally use, just make sure you select something big enough to suit the size cable you are installing into it.
As I said above I'd probably reduce the cable size for the final terminations to allow a regular 100A switchfuse to be used for the supply.

I was goijg to TT this at each connection point with the runs being so long

What do you mean by this? TT is an earthing system and describes that characteristic of the supply, it's not a thing you can do at connection points.

 

[R-fur]

Once you have designed your switchgear layout, You could try, New Circuit engineering, Close Engineering or Blackburn Starling to manufacture for you.
The DNO will normally want an isolator within three meters of the meter, you will then need protection for your sub circuits.