Chasing cable in a ceiling

[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.