Melting

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sparky999

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Evening guys

Been on wiring an extension 2day and the builder mentioned that we should use metal capping on the external walls.

We asked why and he said he had been told on previous job on a barn conversion that building control told him that they had to use metal capping as the BC had been on another job and the plastic capping melts when behind themal boarding.

Anyone heard of this before or is it common knowlege?

 

heathelect

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Evening guysBeen on wiring an extension 2day and the builder mentioned that we should use metal capping on the external walls.

We asked why and he said he had been told on previous job on a barn conversion that building control told him that they had to use metal capping as the BC had been on another job and the plastic capping melts when behind themal boarding.

Anyone heard of this before or is it common knowlege?
sounds like rubbish to me, never heard of it or seen it !!!!!!!!!!!!!!!!!!!

 

Evans Electric

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I don't think its melting, you 'd need an flame or heat gun !!! It may be reacting with polystyrene as cable PVC does . The molecules start to migrate , don't know which way but I've come across cable becoming sticky .

Deke

 

ABC Technical

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It does sound like a load of horse doo doo to me, never heard or seen it before, but I may be wrong?

 

sparky999

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Yh never heard of it.

We put it in anyway to keep the builder happy.

The boss wasnt very happy as he had to get some metal capping for us of the wholesaler :^O

 
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no1electrician

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sounds like the bc is talking about plastic migration and then it became chinese whispers

 

sparky999

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Bond the metal capping?

No i never you dont have to bond metal capping do u?

 

Theorysparky

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No way ho-say. Capping is not acceptable for that reg ( can't be ****d to look it up ) because it is easily pierced and not usually earthed
Not used it before,,assumed it would be similar to in thickness to metal conduit..

learnt something today.........

 

septiclecky

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Bond the metal capping?No i never you dont have to bond metal capping do u?
You need to read the 17th edition.

Cables that are not deeper than 50mm have to be protected by earthed metal protection.

Metal capping does not offer the protection required as stated earlier due to the fact you can easily put a nail through it.

 

sparky999

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Yeah thats where a RCD comes into effect doesnt it or rcbo to overcome this problem.

 

sparky999

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See i do listen to a few things hehe :^O

until Guiness DrinkGuiness Drink

 

SPECIAL LOCATION

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Not used it before,,assumed it would be similar to in thickness to metal conduit..learnt something today.........
IMHO

Metal capping aint that much thicker that what comes on a roll and you wrap around the Turkey at Christmas.. :^O :^O:^O

 
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your right sparky

capping is fine for mechanical protection only, its not the same as metalic conduit, doesnt need earthing and isnt designed to meet the new 17th ed regs on protection of cables.

you should either use earthed metalic conduit, OR an rcd/rcbo

i know which id use

 
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