Discuss Chasing cable in a ceiling in the DIY Electrical Advice area at ElectriciansForums.net
Got you now.@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.
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.The regs say 50mm below the surface, why do you think this only applies to walls only?
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.
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.
Like I said it is unconventional.
You aren't supposed to notch the bottom of joists.
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.
Nobody puts anything on a ceiling apart from a light...
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.
pages 3,4,9,10 and 12 of approved document PI 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
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.
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.
Section 522.6.1 says "shall be erected to minimise damage from mechanical stress".
"In continuum mechanics, stress is a physical quantity that expresses the internal forces that neighboring particles of a continuous material exert on each other" wikipedia
My cable is not under any stress.
protection shall be afforded by characteristics of the wiring system
Yes, an RCD
If you believe you are compliant with building regulations then that's great, but surely you would only know if you requested a building reg person to assess and approve your work?
That is not the case at all.BS7671 requires that cables should be protected against impact, abrasion, penetration, tension or compression.
BS7671, is therefore in breach of it's own rules, because it allows a cable to be run less than 50mm in a wall, under plaster when protected by a RCD. If it is good enough for the goose it is good enough for the gander. If they consider it to be safe in a wall, then I consider it to be safe in a ceiling.
So in a nutshell
OP: I've done something I think might not be right, what do you lot think ?
Forum: We think it is not right
OP: Well what do you lot know, why don't you all shut up ?
Quality thread.
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