Meter Tails to CU

[GaryMo]

Put your Hilti away!

 

[NotHimAgain]

The Electrical Safety Council support the use of 3 mm plate, as you have suggested - provided the use of shot fired nails is unlikely .

See here - look for NDQ12/NDA12
http://www.esc.org.uk/forum/forum_nd_thread.html

 

[GaryMo]

Its not likely in a domestic kitchen

 

[GaryMo]

A manufactured 3mm steel plate silimar to the profile of capping to cover the tails would suffice and wouldn't require earthing.

Yes it would require earthing. why do you think it wouldn't. It's a metal barrier and as such the same as galv conduit or trunking.

Chris, have a read of 522.6.6(iv)

 

[ban-all-sheds]

However, the interesting question is would it be strong enough to prevent penetration by nails screws and the like .

Wouldn't have to be if it was earthed.

If I understand the 17th edition correctly

Err.... No.

Do you have a copy? Should do if you're doing the installation design.

then I have the following options:

1. Bury the meter tails in excess of 50mm into the internal blockwork and run them to the CU. I understand that they must also be run within the safe zones.

If they are >50mm deep they can be anywhere. If they are <50mm deep and not mechanically protected etc they will need to be in safe zones and be RCD protected.

How thick is the inner leaf? Is >50mm achievable?

2. Mechanically protect the tails with steel conduit and run to the CU. This conduit would also require earthing.

Conduit would not require earthing if the cables are more than 50mm deep. But then at >50mm conduit isn't needed anyway.

Or have you got metallic parts in the wall? Does 522.6.8 apply?

Or are you planning to use the conduit as the earth conductor?

Option 1 also entails a large degree of channelling which is time consuming.

So if you used conduit would you not bury it?

And anyway - new house - blockwork - use a chasing tool and SDS chisel, won't take long.

Option 2 has the issue of still having to channel the conduit partly into the wall so as it won't be seen and earthing it.

Earthing conduit is not hard.

Anyone think of any other options?

Just use SWA or pyro and be done with it.

 

[GaryMo]

Anyone think of any other options?

Just use SWA or pyro and be done with it.

For main tails?

 

[ban-all-sheds]

Why not?

(Other than the usual reasons)

 

[GaryMo]

However, the interesting question is would it be strong enough to prevent penetration by nails screws and the like .

Wouldn't have to be if it was earthed.

Metal capping isn't strong enough to prevent penetration by nails, screw and the like. Are you suggesting it would be adequate if it was earthed?

 

[GaryMo]

Why not?

It would involve a lot of messing about. You couldn't connect either directly into the meter terminals so you would need at least one connection involving DI tails.

 

[ban-all-sheds]

Metal capping isn't strong enough to prevent penetration by nails, screw and the like. Are you suggesting it would be adequate if it was earthed?

Err - wasn't it my turn to not read all of 522.6 properly?

(iv) doesn't say that mechanical protection needs earthing, but of course capping is neither incorporated into the cable, nor is it BS EN 61386 conduit or 50085 trunking or ducting.

So no - it wouldn't be adequate if earthed.

 

[ban-all-sheds]

It would involve a lot of messing about. You couldn't connect either directly into the meter terminals so you would need at least one connection involving DI tails.

Why couldn't swa or pyro be glanded to the enclosure of the switchfuse in the meter cabinet?

 

[Chri5]

A manufactured 3mm steel plate silimar to the profile of capping to cover the tails would suffice and wouldn't require earthing.

Yes it would require earthing. why do you think it wouldn't. It's a metal barrier and as such the same as galv conduit or trunking.

Chris, have a read of 522.6.6(iv)

Thanks Gary

 

[GaryMo]

It would involve a lot of messing about. You couldn't connect either directly into the meter terminals so you would need at least one connection involving DI tails.

Why couldn't swa or pyro be glanded to the enclosure of the switchfuse in the meter cabinet?

Sorry BAS, I got carried away and forgot he had a switch fuse and not just a DNO meter to connect to.

I still wouldn't a*se around with pyro of that size though!

 

[ban-all-sheds]

16mm²?

Rob will come and do it - he has a BBW fetish.







































































(That's Big Beautiful Wiring, you filthy beasts)

 

[martinxxxxxx]

Must the cables be hidden in the wall?

You could surface-mount them or use surface trunking or maybe run them under the floor.

No one noticed this very good option, which is prob what I would be doing unless someone tells me that there is a flaw here?

Martin