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.

 

[Deleted member 26818]

At the end of the day, it's your flat.
If you want to do something which doesn't comply that's your choice.
It will only become a problem if you forget where the cable is run and bang a nail into or screw something into the cable. Or if you sell the place, rent it out and the new owner or tenant does it.

There's no requirement for you to notify this work, so Building Control will not know about it and will not issue an improvement notice.

Whilst RCD protection may make things safer, it is not a acceptable method for complying with the Regulations.

So your options are:
Re-run the cable on the surface of the ceiling,
Re-run the cable using a cable with an earthed metallic sheath,
Re-run the cable, chasing it into the ceiling to a depth greater than 50mm,
Provide mechanical protection for the part of the cable that is plastered over,
Re-run the cable in earthed conduit and plaster the conduit into the ceiling,
Hope that nothing goes wrong.

 

[Pat H]

Assuming of course that the joist notches are within the specified range on the joist.

 

[Pat H]

How can the cable be plastered in the ceiling thickness? I assumed its loose between joists.
That's what I would have done. cut a circular hole each side of each joist. Chase across the joist and into the joist.
Metal plate over the joist notch. Cable free to move. Cable free to move between joists.
That way, if need be, a replacement cable can be pulled through the whole length if it gets damaged etc.
Then plaster the holes and over the metal plates ensuring the cable isn't glued by the plaster.

 

[Deleted member 26818]

Yes, does seem weird.
Saw post #8, which is why I asked the question in post #9.

 

[Pat H]

If you chase right through a plasterboard ceiling you end up with two flaps that will move around even after a plaster patch.

 

[Wilko]

Hi - according to OP post #8
"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" .
Must be a thick plaster ceiling?

 

[Pat H]

Hi - according to OP post #8
"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" .
Must be a thick plaster ceiling?

As long as its more then 50mm thick and the cables at the top. then all's fine ;-)

 

[westward10]

I would have liked to have seen some before and after pics.

 

[Leesparkykent]

You aren't supposed to notch the bottom of joists.

 

[westward10]

You aren't supposed to notch the bottom of joists.

Not sure he has, I think he has just cut a channel across the plasterboard.

 

[Pat H]

Thats true. Better to have drilled a hole but you would then need to make much larger access holes in the plaster at least on one side of the joist.

 

[Leesparkykent]

@westward10 I tried quoting @Pat H posts #22/23 about notching joists from below but for some reason I'm getting an error when trying to quote.

 

[westward10]

@westward10 I tried quoting @Pat H posts #22/23 about notching joists from below but for some reason I'm getting an error when trying to quote.

Got you now.

 

[Gigsy]

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

Thank you everyone, this one seems a bit of a grey area. Some qualified electricians think it complies with regs, and some think it does not. Here are a few of my thoughts.


Yes the plaster is thicker than the cable.

The cable is covered by plastic capping.

The 50mm below a floorboard and 50mm above a ceiling to avoid nails is not relevant as it does not go through a joist.

You can run cable un-protected by grounded metal conduit less than 50mm in a wall as long as it is protected by a RCD, so why can't you do the same in a ceiling?

I do not think my work contravenes any regulations.


Also please do not talk to me like I am thick, just cos I am not qualified as an electrician does not mean I cannot read BS7671, I have a copy of the manual and am more than capable of understanding it, I have come here to see if there is anything in the book I have missed. So far I am confident that all the regs that have been quoted in this thread have not been broken. It is quite astonishing how some of the replies in this thread quote regulations that simply do not apply to the situation, it appears to me that some of the electricians in this forum do not actually understand the meaning of the words they write.

 

[Leesparkykent]

Hi @Gigsy , I don't want to come across as rude or condescending but you are deluded if you generally think that nearly every reg that's been mentioned in this thread hasn't been contravened by what you have done.

The reason cables can be buried in a wall at a depth of less than 50mm as long as it has additional protection my means of a 30mA RCD is because they are run in prescribed zones i.e 150mm from a corner of a wall, 150mm from the top edge where wall meets ceiling, Horizontal and vertical from an accessory.

 

[westward10]

I don't think it was anyone's intention to judge your interpretation of BS7671. I think the problem was the unconventional way as to which you installed the cable and finding whether it was compliant or not, which obviously led to opinions of your methods which I found quite amusing, no offence meant.

 

[Gigsy]

Hi @Gigsy , I don't want to come across as rude or condescending but you are deluded if you generally think that nearly every reg that's been mentioned in this thread hasn't been contravened by what you have done.

The reason cables can be buried in a wall at a depth of less than 50mm as long as it has additional protection my means of a 30mA RCD is because they are run in prescribed zones i.e 150mm from a corner of a wall, 150mm from the top edge where wall meets ceiling, Horizontal and vertical from an accessory.

Why are

Hi @Gigsy , I don't want to come across as rude or condescending but you are deluded if you generally think that nearly every reg that's been mentioned in this thread hasn't been contravened by what you have done.

The reason cables can be buried in a wall at a depth of less than 50mm as long as it has additional protection my means of a 30mA RCD is because they are run in prescribed zones i.e 150mm from a corner of a wall, 150mm from the top edge where wall meets ceiling, Horizontal and vertical from an accessory.

Explain how regulation 522.6.201 has been contravened, under a floor or above a ceiling, I did not install the cable under a floor or above a ceiling. This regulation is irrelevant

Explain how regulation 522.6.204 has been contravened. This regulation deals with cables running through holes in joists, I have not run cable through a hole in a joist,. This regulation is irrelevant.


Concerning the regulations regarding permitted area's in walls, these regulations do exactly what they say on the tin, they deal with permitted area's to run cables in regard to walls, I have not run my cable in a wall, I have run my cable in a ceiling.


Regarding the building regulations, all it says in part P of the building regulations is that electrical installations have to be safe and not cause fire or electric shock. BS7671 are not a legal requirement, just helpful guidelines you can follow to help you prevent installing an electrical system which could potentially cause a fire or electric shock.


Chasing a cable in a ceiling to an appliance and protecting it with a RCD, is not likely to cause a fire or cause anyone to receive an electric shock. Nobody puts anything on a ceiling apart from a light, the cable goes to the light.

 

[westward10]

Like I said it is unconventional.

 

[Gigsy]

Like I said it is unconventional.

Thank you, I think that explains the reaction

 

[telectrix]

where the cables pass under the joists, a steel protection plate could be fitted under the cables, fixed int the joists. to comply. personally, i'd not bother. tin hat on.

 

[Pat H]

Protected by an RCD covers most things. But don't think a ceiling is not vulnerable to nails.
What happens if the next owner decides to hand ceiling decorations and screws a cup hook into the plaster?

Regulations have to be followed but its also about protection from possible dangers. As I said an RCD covers of that anyway.

 

[jackhammerJIM]

You aren't supposed to notch the bottom of joists.

PLUMBERS !!!

 

[Darkwood]

Thank you everyone, this one seems a bit of a grey area. Some qualified electricians think it complies with regs, and some think it does not. Here are a few of my thoughts.


Yes the plaster is thicker than the cable.

The cable is covered by plastic capping.

The 50mm below a floorboard and 50mm above a ceiling to avoid nails is not relevant as it does not go through a joist.

You can run cable un-protected by grounded metal conduit less than 50mm in a wall as long as it is protected by a RCD, so why can't you do the same in a ceiling?

I do not think my work contravenes any regulations.


Also please do not talk to me like I am thick, just cos I am not qualified as an electrician does not mean I cannot read BS7671, I have a copy of the manual and am more than capable of understanding it, I have come here to see if there is anything in the book I have missed. So far I am confident that all the regs that have been quoted in this thread have not been broken. It is quite astonishing how some of the replies in this thread quote regulations that simply do not apply to the situation, it appears to me that some of the electricians in this forum do not actually understand the meaning of the words they write.

It wasn't a dig at you or your intelligence, you seem to have snapped back a little to harshly on my comment, I just ask a genuine query as to why you think the regulation only applies to certain planes in the building structure, where did I undermine your intellect or challange your intelligence?
The BS7671 is a very complex set of regulations and many are ambiguous so down to interpretation hence I asked why you had that line of thought.

Personally I cannot see why you wouldn't apply this regulation to all surfaces as this is how it is worded, you can get many fixtures and fitting that mount on a ceiling and screw down to a floor so why the abrasive reaction?

 

[HandySparks]

Nobody puts anything on a ceiling apart from a light...

Or drawing pins for decorations. Or a battery smoke alarm.

 

[Taylortwocities]

Or a PowerMyself Health and Fitness Supplement Store PowerMyself Ceiling Mounted Chin-Up Bar - English - https://www.powermyself.com/powermyself-ceiling-mounted-chin-up-bar.html

 

[Richard Burns]

Effectively the cable is run above a very thin layer of the ceiling i.e. the plaster covering the cable.
The cable itself is not protected against penetrative impacts such as nails and screws.
There is no indication that the cable is present as it has been plastered over.
A significant possibility exists that the ceiling may need to be repaired or an item may need to be fixed to a ceiling within the lifetime of the installation.
In the case of someone working on or at the ceiling, since it is not possible to identify that the cable is there, someone may damage the cable inadvertently, giving rise to the possibility of electric shock.
This is something that is to be avoided in the installation of a cable and there are no options specified to prevent this for your cable type and installation location.
Whilst approved document P can be a little woolly in its wording it does state that electrical installations should be designed to comply with BS7671.

 

[Wilko]

Hi - a bit of overnight thinking, for what it's worth. The technique seems novel and seems not specifically referenced to either exclude or include in BS7671, that I could see. However, that doesn't mean BS7671 doesn't apply or has nothing to say. Being concerned about impact to the cable that is now part of the ceiling Chapter 52 Selection and Erection of Wiring Systems seems relevant. Reading 522.6 Impact, it begins as an inclusive statement and so applies in this case, IMHO. Section 522.6.1 says "shall be erected to minimise damage from mechanical stress". Then 522.6.2 says "protection shall be afforded by characteristics of the wiring system". At present what you describe does not satisfy these directives. IMHO a fit for 6.1 could be to have it buried out of harms way and not fixed and concealed just mm below the surface. Or for 6.2 could be to make it using steel conduit or SWA.

 

[Deleted member 26818]

No it is not specifically referred to in BS7671, because it's not really a viable option.
BS7671 requires that cables should be protected against impact, abrasion, penetration, tension or compression.
One method is to run cables above a ceiling, ensuring that if a cable passes through a joist, that it is more than 50mm from the surface of the ceiling, mechanically protected against penetration from nails or screws, etc, etc.
This cable has not been run above a ceiling so another method of protection is required.
Other methods are earthed sheath, conduit or trunking, mechanical protection or by placing the cable in a location where it will not suffer any damage.
Concealing the cable within the fabric of the ceiling would only comply if there is a guarantee that no one would ever pierce the cable.
So somewhere that no one would put a hanging basket, punch bag, decorative plaster casts, model airplanes, hanging seats, friparies to hang over a bed, Christmas decorations, speakers, fly paper, insectocuters, etc, etc.

 

[Gigsy]

E
Whilst approved document P can be a little woolly in its wording it does state that electrical installations should be designed to comply with BS7671.

I think you may be referring to the approved document which explains how to comply with Part P of the building regulations. Can you show mw where in the actual building regulations, in Part P, it refers to BS7671?

 

[Leesparkykent]

I think you may be referring to the approved document which explains how to comply with Part P of the building regulations. Can you show me where in the actual building regulations, in Part P, it refers to BS7671?

pages 3,4,9,10 and 12 of approved document P