Tails or SWA?

[HappyHippyDad]

My customers meter is being moved. The distance to the consumer unit will be approx 10m. I'll be installing a metal switched fuse in the meter. I cannot run any cables up the outside as it is having some kind of wooden finish and the customer does not want anything else on show.

I can only see 2 other choices. Run it up the cavity of the brick wall, or bring it through into the house and run it up a chase in the inner wall. I have never routed cables in the cavity before but would this be ok if it was a) SWA b) tails in steel conduit?

Also, the same question applies to bringing the cable(s) into the house and up a chase in the inner wall (it may be dot and dab). Would it be ok if the tails were in steel conduit?

I realise both options meet the regulations (522.6.204) (i.e. SWA or tails in steel conduit), but I have always brought it up the outside of the house before and just wanted get some opinions.

 

[MJPD29]

I think I'd opt for swa chased into the wall I'm not keen on running cables in a cavity and it would be tough to get the tails into conduit you'd probably end up with trunking so swa would save that hassle

 

[Toneyz]

I assume that you want to get from the meter box into the joist void then down to the new consumer unit position?
What size tails was you thinking of as if 25mm with 16mm earth you will not get up 25mm conduit then you would have to earth it and should that earth connection be accessible for T & I.
If you are considering using the cavity need to consider the transfer of water, derating of the cable if cavity filled with insulation and mechanical damage.
What we used to do for sub-mains when going down to the meter cupboard was chase in wall cover with tails capping and put it inline with a socket.

 

[HappyHippyDad]

I assume that you want to get from the meter box into the joist void then down to the new consumer unit position?
What size tails was you thinking of as if 25mm with 16mm earth you will not get up 25mm conduit then you would have to earth it and should that earth connection be accessible for T & I.
If you are considering using the cavity need to consider the transfer of water, derating of the cable if cavity filled with insulation and mechanical damage.
What we used to do for sub-mains when going down to the meter cupboard was chase in wall cover with tails capping and put it inline with a socket.

Let's assume it'll be 25mm tails and 16mm earth. This would fit in 32mm steel copex. Copex could be earthed in the switch fuse.
Yes, up to the ceiling void and then down to the CU, so to be honest I'm really urging towards tails as SWA would need to be terminated into a separate enclosure by the CU.

 

[Andy78]

Let's assume it'll be 25mm tails and 16mm earth. This would fit in 32mm steel copex. Copex could be earthed in the switch fuse.
Yes, up to the ceiling void and then down to the CU, so to be honest I'm really urging towards tails as SWA would need to be terminated into a separate enclosure by the CU.

I'd go for SWA every time in this situation. Copex would not comply with the relevant regs for mechanical protection for buried cables as it mentions specific BS standards. Unless I'm not keeping up with the planned route.

 

[Toneyz]

Let's assume it'll be 25mm tails and 16mm earth. This would fit in 32mm steel copex. Copex could be earthed in the switch fuse.
Yes, up to the ceiling void and then down to the CU, so to be honest I'm really urging towards tails as SWA would need to be terminated into a separate enclosure by the CU.

I don't think that metal flexible conduit can be used as not a reliable earthing conductor?

 

[davesparks]

Let's assume it'll be 25mm tails and 16mm earth. This would fit in 32mm steel copex. Copex could be earthed in the switch fuse.
Yes, up to the ceiling void and then down to the CU, so to be honest I'm really urging towards tails as SWA would need to be terminated into a separate enclosure by the CU.

Metal flexible conduit is not suitable for this, if you are going to use steel conduit then it needs to be the proper stuff, not flexible.
Flexible metal conduit is not suitable for use as a CPC or any other sort of protective conductor so it cannot be used as an earthed metal covering for the purpose of burying cables.

Steel conduit is fine for this task, you can use singles rather than tails and the conduit can form the CPC is properly installed. I cant see that you would need more than a 63A circuit unless this house is unusually large?

 

[davesparks]

If it is just a question of burying tails in the wall then a thick steel plate over the chase will do the job of protecting them.

 

[Toneyz]

If it is just a question of burying tails in the wall then a thick steel plate over the chase will do the job of protecting them.

This is what I was referring to in my previous post our local wholesaler seles this special metal tails capping that can resist nails and screws etc. I always liked to have an accessory inline with it to indicate cable zone.

 

[ipf]

What about swa terminated in a metal adaptable box sunk in the wall behind the CU. Should be simple enough if it's dot and dab...everything rear entry. Just make sure your entry areas for all cables are clear.

 

[HappyHippyDad]

I assume that you want to get from the meter box into the joist void then down to the new consumer unit position?
What size tails was you thinking of as if 25mm with 16mm earth you will not get up 25mm conduit then you would have to earth it and should that earth connection be accessible for T & I.
If you are considering using the cavity need to consider the transfer of water, derating of the cable if cavity filled with insulation and mechanical damage.
What we used to do for sub-mains when going down to the meter cupboard was chase in wall cover with tails capping and put it inline with a socket.

Could you give a link to this suitable capping please Anthony?

 

[Bobster]

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word words words words

 

[HappyHippyDad]

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Perfect! Where do you buy it?
Edit.. found their number, I'll give them a ring, thanks

 

[Bobster]

Perfect! Where do you buy it?
Edit.. found their number, I'll give them a ring, thanks

33 Dawley Trading Estate,
Stallings Lane, Kingswinford,
West Midlands DY6 7AP


Tel: 01384 401700 / 401600
Fax: 01384 292785
Email: [email protected]

I've never used it, just remember seeing it recommended before on here and copied the link.

 

[Silly Sausage]

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He just needs a bigger drill

 

[davesparks]

This is what I was referring to in my previous post our local wholesaler seles this special metal tails capping that can resist nails and screws etc. I always liked to have an accessory inline with it to indicate cable zone.

I used to just get thick steel plate from the people who supplied us RSJs and other steelwork.

 

[Bobster]

He just needs a bigger drill

I mean, it's only to offer protection against accidental damage.

If some clown wants to take a stihl saw to a wall, there isn't much you can do in a domestic environment to protect something.

 

[davesparks]

I mean, it's only to offer protection against accidental damage.

If some clown wants to take a stihl saw to a wall, there isn't much you can do in a domestic environment to protect something.

Some sugar in the petrol tank should protect against that one.

 

[Toneyz]

Could you give a link to this suitable capping please Anthony?

We have had it from Midshires Electrical Wholesalers in Northampton, but I think edmundsons can get it

 

[Toneyz]

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This is what we have fitted before.