MAX LENGTH FOR METER TAILS?

[JOHNNY55]

Hi all i have read the other threads on this subject but am going to post this anyway just to get things clear in my head...well tryto anyway lol.

im going to be moving a C.U from one side of a room to the other. About 6m. it is in a small terraced house,two up two down, am i right in thinking that as long as i install a Fused Isolator. (was going to use the 60A wylex type as this will give me some discrimination before the 80A EDF fuse)

Then i should be able to install the 25mm tails up to this length? they are going to be installed outside the house in a trunking then through the wall and into the new C.U position.

I have looked up in the O.S.G page 17 and looked at the regs it reffers to but can not find any deffinate answers. If you know what REG i should be looking at then i would like to know that aswell please for future refferance and all that

thanks for taking the time to read this lot

John

 

[Andy™]

i wouldnt use trunking outside. apart from that, everything else seems good

 

[steptoe]

25mm SWA outside, and your isolator is fine, might want to use a MC one tho if you use SWA.

its a DNO issue as to the length of the tails.

 

[hatha101086]

From past experience i believe its roughly 3m, however you should speak to the supplier before work begins as they may be happy for it to be extended further, obviously they will need to come out as well to remove the fuse at the meter so its done properly....

 

[Evans Electric]

I don't think the DNO care one way or another these days , but if you fit your own fuse anyway its nowt to do with them.

 

[SparkyMarky]

When you say before the EDF 80A fuse presumabley you mean after? You haven't said what kind of supply it is. If it's TN then I would run 3 core SWA from your switch fuse and terminate it in an adaptable box next to the CU and then run the cores directly in but if it's TT you'll need to RCD it as well.

 

[Nicky Tesla]

2 points.

1. A lower fuse rating doesnot necessarily mean discrimination. You can use the same rating, but a different BS and the graphs will show that the 1st fuse will blow first. It can be complicated though.

2. Can concentric cable be used, i know our local wholesaler sells it.

 

[Andy™]

straight concentric, no. split concentric, yes