Chasing cable in a ceiling

[Gigsy]

I wonder if anyone can advise me about some work I have done in my living room in regard to the building regulations. I needed to install a light in the centre of the room. I could not access the joists from via the floorboards upstairs due to the fact a bathroom floor had recently been tiled. There are noggins between the joists so rodding was not an option. The only option available was to chase out the ceiling. I intended to drill through the joists with access from the ceiling, but instead I thought it would be easier to just use capping, so I nailed capping to the bottom of the joists and ran the cable through the capping. I am worried now that this work may not be compliant with the building regulations. I can't find anywhere in the regs that forbids this, but I may have missed something. Can someone please advise me.

 

[Richard Burns]

It does not meet the requirements of the wiring regulations and so would not meet the building regulations.

522.6.201 A cable installed under a floor or above a ceiling shall be run in such a position that it is not liable to be damaged by contact with the floor or the ceiling or their fixings.
A cable passing through a joist within a floor or ceiling construction or through a ceiling support (e.g. under floorboards), shall:
(i) be at least 50 mm measured vertically from the top, or bottom as appropriate, of the joist or batten, or
(ii) Comply with Regulation 522.6.204.

522.6.204 For the purposes of Regulation 522.6.201 (ii)… a cable shall
(i) incorporate an earthed metallic covering which complies with the requirements of these Regulations for a protective conductor of the circuit concerned, the cable complying with BS 5467, BS 6724, BS 7846, BS 8436 or BS EN 60702-1, or
(iii) be installed in earthed conduit complying with BS EN 61386-21 and satisfying the requirements of these Regulations for a protective conductor, or
(iv) be enclosed in earthed trunking or ducting complying with BS EN 50085-2-1 and satisfying the requirements of these Regulations for a protective conductor, or
(v) be provided with mechanical protection against damage sufficient to prevent penetration of the cable by nails, screws and the like, or
(vi) form part of a SELV or PELV circuit meeting the requirements of Regulation 414.4.

 

[Wilko]

Are there noggins on all approaches to the centre of the room? Maybe you can come around the room using a "permitted cable route" within 150mm of the ceiling then rod across? The wall cable could be chased or clipped and hidden under some nice cornice. The light circuit would now need RCD for additional protection. Just a thought and happy for feedback. Cheers.

 

[Taylortwocities]

The 'rodded' cable will then lie loose on the plasterboard, and would not achieve the 50mm distance requirement.

 

[Wilko]

The 'rodded' cable will then lie loose on the plasterboard, and would not achieve the 50mm distance requirement.

Oops - you are quite right of course. Looks like a proper bit of hole cutting and plastering will be required. Then it could go direct which is much better anyway.

 

[Deleted member 26818]

The 50mm applies to where cables run through joists or battens.
There is no minimum depth between the joists or battens.

 

[Gigsy]

Are there noggins on all approaches to the centre of the room? Maybe you can come around the room using a "permitted cable route" within 150mm of the ceiling then rod across? The wall cable could be chased or clipped and hidden under some nice cornice. The light circuit would now need RCD for additional protection. Just a thought and happy for feedback. Cheers.

As far as I know there are noggins on all approaches, I don't have access from all sides to find out. The 150mm "permitted cable route" tip has given me an idea that may work, I may be able to put the light off center if i come across one of the walls, before one of the noggins. So I can run cable 15cm down from the ceiling across a wall, even if it does not go to an appliance , is that right?

 

[Gigsy]

It does not meet the requirements of the wiring regulations and so would not meet the building regulations.

522.6.201 A cable installed under a floor or above a ceiling shall be run in such a position that it is not liable to be damaged by contact with the floor or the ceiling or their fixings.
A cable passing through a joist within a floor or ceiling construction or through a ceiling support (e.g. under floorboards), shall:
(i) be at least 50 mm measured vertically from the top, or bottom as appropriate, of the joist or batten, or
(ii) Comply with Regulation 522.6.204.

.

Richard, it is this regulation which has me confused, because it states above a ceiling or under a floor. Technically what I have done is not under a ceiling it is actually in the ceiling. The cable is plastered over, it technically forms a part of the ceiling and is not liable to damage from the ceiling or any of its fixings

 

[Deleted member 26818]

There are no permitted routes under a floor or above a ceiling.
Are you saying that the whole cable is plastered over, or just where it runs under or through a joist?
There are special plates that you can obtain from builders merchants or electrical wholesalers that will prevent the cable being pierced by nails or screws.

 

[Gigsy]

There are no permitted routes under a floor or above a ceiling.

Are you saying that the whole cable is plastered over, or just where it runs under or through a joist?

There are special plates that you can obtain from builders merchants or electrical wholesalers that will prevent the cable being pierced by nails or screws.

I do not understand what you are saying, of course you can run cable under a floor or above a ceiling, that is where 80% of cable is run.


522.6.201 A cable installed under a floor or above a ceiling shall be run in such a position that it is not liable to be damaged by contact with the floor or the ceiling or their fixings.

A cable passing through a joist within a floor or ceiling construction or through a ceiling support (e.g. under floorboards), shall:

(i) be at least 50 mm measured vertically from the top, or bottom as appropriate, of the joist or batten, or

(ii) Comply with Regulation 522.6.204.

 

[Gigsy]

There are no permitted routes under a floor or above a ceiling.
Are you saying that the whole cable is plastered over, or just where it runs under or through a joist?
There are special plates that you can obtain from builders merchants or electrical wholesalers that will prevent the cable being pierced by nails or screws.

Whole cable is plastered, cable is attached to underside of the joists in the ceiling, then plastered over. I chased into the ceiling.

 

[Leesparkykent]

Whole cable is plastered, cable is attached to underside of the joists in the ceiling, then plastered over. I chased into the ceiling.

What you've done doesn't comply with BS7671 (the regs to which electricians operate) so consequently doesn't meet building regs.

 

[Wilko]

As far as I know there are noggins on all approaches, I don't have access from all sides to find out. The 150mm "permitted cable route" tip has given me an idea that may work, I may be able to put the light off center if i come across one of the walls, before one of the noggins. So I can run cable 15cm down from the ceiling across a wall, even if it does not go to an appliance , is that right?

Reg 522.6.202 is the one I'm thinking of here - "be installed in a zone within 150mm from the top of the wall ... " . Best if you have read of it to ensure it applies in your situation.

 

[Deleted member 26818]

I permitted routes are only in walls.
Internal corners, near the ceiling and horizontally and vertically from accessories.
Laying cables above ceilings is fine, but there are no permitted routes.
Usually it is only where cables run through joists or battens that extra precautions are required.
In the gaps between the joists, cables aren't held in place, so screws or nails will just push them aside.
Where cables are held in place as the pass through joists, the cables have to be 50mm deep, have mechanical protection or have an earthed sheath.
If you have plastered the whole cable, you only real option is to change the cable for one with an earth d sheath, because the cable is held in place the whole length.

 

[Gigsy]

I permitted routes are only in walls.
Internal corners, near the ceiling and horizontally and vertically from accessories.
Laying cables above ceilings is fine, but there are no permitted routes.
Usually it is only where cables run through joists or battens that extra precautions are required.
In the gaps between the joists, cables aren't held in place, so screws or nails will just push them aside.
Where cables are held in place as the pass through joists, the cables have to be 50mm deep, have mechanical protection or have an earthed sheath.
If you have plastered the whole cable, you only real option is to change the cable for one with an earth d sheath, because the cable is held in place the whole length.

I know BS7671 provides recommended permitted routes in walls. BS7671 are guidelines which if you follow help you comply with the building regulations and therefore the law. I can not see anywhere in the wireing regs that forbid me to chase a ceiling and run a cable in the ceiling. I do not think this is dangerous if protected by an RCD. The regs state rules for running cable in walls and in the gap between the ceiling and floor boards. It does not forbid, let alone mention chasing ceilings. If it is not forbidden in the regs, or not even mentioned in the regs, is it then illegal to do? I have installed a cable in a ceiling. I chased the ceiling ran a cable under plastic capping, then plastered the ceiling.

 

[Gigsy]

I permitted routes are only in walls.
Internal corners, near the ceiling and horizontally and vertically from accessories.
Laying cables above ceilings is fine, but there are no permitted routes.
Usually it is only where cables run through joists or battens that extra precautions are required.
In the gaps between the joists, cables aren't held in place, so screws or nails will just push them aside.
Where cables are held in place as the pass through joists, the cables have to be 50mm deep, have mechanical protection or have an earthed sheath.
If you have plastered the whole cable, you only real option is to change the cable for one with an earth d sheath, because the cable is held in place the whole length.

I know BS7671 provides recommended permitted routes in walls. BS7671 are guidelines which if you follow help you comply with the building regulations and therefore the law. I can not see anywhere in the wireing regs that forbid me to chase a ceiling and run a cable in the ceiling. I do not think this is dangerous if protected by an RCD. The regs state rules for running cable in walls and in the gap between the ceiling and floor boards. It does not forbid, let alone mention chasing ceilings. If it is not forbidden in the regs, or not even mentioned in the regs, is it then illegal to do? I have installed a cable in a ceiling. I chased the ceiling ran a cable under plastic capping, then plastered the ceiling.

 

[Darkwood]

The regs say 50mm below the surface, why do you think this only applies to walls only?

 

[Leesparkykent]

Cables need to be at least 50mm from the top or bottom of the joist/baton it passes through. If its not 50mm from the top or bottom there needs to be something sufficient enough to stop the penetration of nails, screws and the likes of. This method is normally harder to achieve so using a cable which has an earthed metallic covering is an easier alternative.

Other methods are available but in your situation are not practical to use such as be installed in earth conduit, enclosed in earthed trunking/ducting or forms part of a SELV or PELV circuit.

If these methods are used the earthed metallic covering of the cable, earthed conduit, earthed trunking/ducting needs to comply with the requirements of a circuit protective conductor.

You have installed a cable that is not 50mm from the top or bottom of the joist, doesn't have sufficient protection to stop the penetration of nails/screws, doesn't have an earthed metallic covering, is not installed in an earthed conduit or earthed piece of trunking/ducting or part of a SELV/PELV circuit.

The work you have done does not comply with bs7671 which is a minimum standard to which we work. Your work doesn't go above and beyond the requirements of bs7671 either so does not comply. As it doesn't comply it consequently doesn't comply with the building regs.

You've come here seeking advice because your worried that the work you've done doesn't comply well it doesn't.

 

[Pat H]

Dig the plaster away at each joist point.
Add a recessed metal plate for protection. (normally used on top of joists but will work under them)
Re plaster. Ensure circuit is RCD protected.

 

[Wilko]

Dig the plaster away at each joist point.
Add a recessed metal plate for protection. (normally used on top of joists but will work under them)
Re plaster. Ensure circuit is RCD protected.

Hi - sorry to say Pat, but this doesn't solve it I think. The cable trapped in the ceiling plaster remains hidden and not in any safe zone and fixed closer than 50mm from the surface.