csa of braided cable?

[Sime]

i've come across a flat braided copper earthing conductor on a TN-S system and i'm not sure how to find the csa of it. I need the csa for the installation cert.

Any ideas?

 

[itselectric]

Basic maths, width times depth equals csa.

 

[Marvo]

Not always, it doesn't necessarily follow it's a 10mm² CSA if the strap is 10mm wide by 1mm thick. We use 25x3mm straps in some of our control panels and they're rated as 25mm² CSA nominal. There is a formula for working it out but I've no idea off hand what it is. I'd consult the strap manufacturers data sheets to be safe.

 

[itselectric]

I stand corrected.

 

[Jay Sparks]

The only time Ive seen this type of cable is off the outer sheath of the main incoming cable. It generally goes to an MET and then a 16mm2 main earth cable is run from there to the cu. If this is waht your refering to, you dont need to know the csa of this bit, you only need to know the csa of the cable from the MET to the cu. If this isnt what your talking about.......ignore what I said and "Im out"!!!


Jay

 

[Marvo]

Yeah, I'm also not sure why you'd come across it on a TN-S, maybe it was used for equipotential bonding. I'll see if I can find more details about the CSA calcs tomorrow when I'm sitting at my office PC.

 

[Jay Sparks]

Yeah, I'm also not sure why you'd come across it on a TN-S, maybe it was used for equipotential bonding. I'll see if I can find more details about the CSA calcs tomorrow when I'm sitting at my office PC.

Lucky begger.lol

 

[Marvo]

Lol, not really, the office sucks and I don't like being there. Unfortunately tomorrow I have no choice

 

[Jay Sparks]

Yeah, I'm also not sure why you'd come across it on a TN-S, maybe it was used for equipotential bonding. I'll see if I can find more details about the CSA calcs tomorrow when I'm sitting at my office PC.

All the ones Ive seen have been on newish service heads. The DNO put a bit of G/Y tape around it. Its only about 6" long at most and goes to one of there METs with the screw/seal on. This is just for the main earth though, Ive never seen it anywere else on domestic.

 

[Jay Sparks]

Lol, not really, the office sucks and I don't like being there. Unfortunately tomorrow I have no choice

At least your somewhere!! Ive been really busy this last week or two but Ive got nowt on for the next week. Im gonna have to stay at home while the snow comes down and watch Jeremy kyle.lol (not).

 

[Sime]

it is from the armor of the incoming cable to the MET... so this isn't the earthing conductor or even part of it?

 

[Marvo]

I'm confused, is it a like a flat copper braid strap or is it armour that forms part of the incoming cable? Can you maybe post a picture?

 

[Jay Sparks]

it is from the armor of the incoming cable to the MET... so this isn't the earthing conductor or even part of it?

If it comes from the armour of the service cable, then on a tn-s system, it is the main earth. But the earth that you need to be concerned with is from the MET to the cu. This is the cable csa you put on your cert, not the braided bit. This is how the DNO engineer sometimes attach the main earth to the installation.


Jay

 

[Sime]

Sorry cant get a pic. It is as Jay has said, by the sound of it.
Id still like to work out the csa incase i come across one in the future on a PIR.

Thanks lads

 

[Baker1988]

If it comes from the armour of the service cable, then on a tn-s system, it is the main earth. But the earth that you need to be concerned with is from the MET to the cu. This is the cable csa you put on your cert, not the braided bit. This is how the DNO engineer sometimes attach the main earth to the installation.


Jay

Yeah I agree with you, on a tn-s the death is connected to the armouring of the incoming cable so no need to know the size of that just from the met too the cu which should be 16 or 10

 

[Engineer54]

I'm confused, is it a like a flat copper braid strap or is it armour that forms part of the incoming cable? Can you maybe post a picture?

It''s the strap from the cables lead sheath to the MET Marvo. It can either be soldered to the sheath or attached via a Hepworth or constant pressure spring clamp!! If it came with the earth clamp as part of a kit, it will generally have a 16mm CSA...

Think the other posters are getting confused between armouring and the lead sheath of a PILC older cable....