cable through to exterior- conduit required?

[jpadie]

hi all 

 

i need to get a 10mm2 t+e cable from a CU through the wall and to the outside of the building.  It's not armoured cable.  

 

my plan is to drill through the wall behind the CU.  the hole will be in the safe zone.  on the outside there is 25mm battening and then fibre cement cladding.  Either I will take the cable up into the soffit and along through the roof beams until it arrives where I need it or I will bring it out through the cladding and take it around the building in conduit.  most likely the second route.

 

my question is about how to bring the cable through the wall (PIR and OSB).  Do the regs require there to be a conduit or can the wire be run through without separate protection?

 

thanks in advance,

justin

 

[Mr Punter]

I think running the cable internally would be better.  I don't think you are not supposed to run cables in the wall cavity, which is what your batten space is.

[jpadie]

6 minutes ago, Mr Punter said:

I think running the cable internally would be better.  I don't think you are not supposed to run cables in the wall cavity, which is what your batten space is.

this isn't a brick wall so not a cavity in the sense of a cavity wall.  the building is timber framed and the cable will be run either in conduit on the outside of the cladding or in the soffits more than 50mm from the base to make a "safe zone").

 

The cable will be for exterior appliances (a car charger perhaps, outdoor sockets).  so it does need to be on the exterior of the building.

[Mr Punter]

When we have done car chargers the sparky did them in armoured cable.

[jpadie]

1 hour ago, Mr Punter said:

When we have done car chargers the sparky did them in armoured cable.

let's ignore what the appliance might be.  Let's assume for the moment that it is an outside light.  Conductors must pass from the CU (directly or indirectly) to the outside.  Do those conductors need to run through conduit if they are not armoured?  

[Russell griffiths]

16 minutes ago, jpadie said:

let's ignore what the appliance might be.  Let's assume for the moment that it is an outside light.  Conductors must pass from the CU (directly or indirectly) to the outside.  Do those conductors need to run through conduit if they are not armoured?  

Yes. You need to protect it from chafing and also provide air sealing to the hole you just made. 
 

[Trojan]

22 minutes ago, jpadie said:

let's ignore what the appliance might be.  Let's assume for the moment that it is an outside light.  Conductors must pass from the CU (directly or indirectly) to the outside.  Do those conductors need to run through conduit if they are not armoured?  

 

Twin and earth isn't an exterior rated cable, not a problem if you're running direct through a wall into the fitting (ideally should be sleeved in a conduit but no ones losing sleep over it). Running it outside is a different story though and would need to be in a conduit, PVC would suffice if it's in an area not subject to mechanical damage. 10mm T+E is thick and fairly inflexible, you'd probably want 25mm conduit to pull that through. 

Any reason you don't want to use armour?

[jpadie]

1 hour ago, Russell griffiths said:

Yes. You need to protect it from chafing and also provide air sealing to the hole you just made. 
 

thank you.  it would not chafe on PIR but possibly on the OSB

[jpadie]

1 hour ago, Trojan said:

 

Twin and earth isn't an exterior rated cable, not a problem if you're running direct through a wall into the fitting (ideally should be sleeved in a conduit but no ones losing sleep over it). Running it outside is a different story though and would need to be in a conduit, PVC would suffice if it's in an area not subject to mechanical damage. 10mm T+E is thick and fairly inflexible, you'd probably want 25mm conduit to pull that through. 

Any reason you don't want to use armour?

thank you.  it will either run through the soffit and be protected from UV or in PVC conduit.  it's the 30cm through the wall thickness that I'm focussed on.  no UV concern there but I was concerned that there may be regulations specifying a requirement for conduit.  the challenge goes to how big the hole through the wall must be and how to anchor the conduit at either end (there is _no way_  to anchor a perpendicular conduit to the CU aesthetically in my situation).  I'll attack this tomorrow!

SWA is a PITA.  It's inflexible and a b***er to work with imo, even disregarding the price.  i'd also need to gland the SWA which means taking it out of the side of the CU, which i don't want to do when there are perfectly serviceable routes through the back.  Lastly, I don't see the need for SWA since there is no chance of the cable being damaged or otherwise outside of a safe zone without being in a visible conduit.  

 

 

[Trojan]

6 hours ago, jpadie said:

thank you.  it will either run through the soffit and be protected from UV or in PVC conduit.  it's the 30cm through the wall thickness that I'm focussed on.  no UV concern there but I was concerned that there may be regulations specifying a requirement for conduit.  the challenge goes to how big the hole through the wall must be and how to anchor the conduit at either end (there is _no way_  to anchor a perpendicular conduit to the CU aesthetically in my situation).  I'll attack this tomorrow!

Fitting, end box. Cut a 25mm hole in the back of the end box and screw in the adapter fitting, small section of conduit siliconed in the fitting and push it all through the hole from outside. Silicone round your hole where it comes through the OSB into your cavity.