Cooker and kitchen power cables to be enclosed in rockwall

[chris murphy]

I've explained twice that there are regulations - just not a regulation prohibiting it as you suggested there ought to be.

Hello again,

The last thing that I wanted to do was to irritate you.

I did refer to what you wrote about there being regulations about this for new build properties with cable types / sizes and runs being designed to allow them to run through various Building materials including insulation without any detrimental effect on the installation.

I was just giving an opinion about insulation being fitted in existing Homes / Buildings on top of or around existing electrical cables.

Chris

 

[felix24]

Hello Felix24,

I have wondered for decades about ownership of the above ceiling / underfloor void from an upstairs flat - I have never been able to find the answer to any property despite over many years asking almost everyone that I know who owns a flat.

I have asked some people whether there is anything at all about this on their deeds but anyone who could access ther detials on their deeds stated that there was no reference to that.

I would have thought that the ceiling would be the upper boundary of a flat ownership although we know that lighting cables for ceiling lights will have been run in the void between the ceiling and the floor above.

The insulation is planned to totally fill the spaces between the joists from above the ceiling to the underside of the floorboards above - approx. 200mm with then insulated plasterboard below that to form the new ceiling.

This is stated to be mainly for soundproofing but also it would help retain heat in the Kitchen which is a big room.

Thanks for your reply.

Chris

Hi Chris,

At the very least, I would advise having a chat with the upstairs neighbour, as there is potential for their electrical installation to be affected. If it does later result in a problem, I would guess the cabling would have to be accessed through your relative’s new ceiling, so probably best to get this sorted now.

If the cable is fully enclosed in 200mm insulation, that will reduce the current carrying capacity of the cable by much more than if the cable just makes contact with the top of the insulation. If there is a way to clip the cables to the underside of the floor joists, so they have air above them for the majority of the run to dissipate heat, that would have less effect. I think it is also permissible to make small notches in the joists, or even to put cables through holes drilled in the centreline of a joist, but again, I would advise involving the upstairs neighbour and a professional electrician before doing anything decisive!

Hope it all gets sorted for you,

Felix

 

[chris murphy]

Hi Chris,

At the very least, I would advise having a chat with the upstairs neighbour, as there is potential for their electrical installation to be affected. If it does later result in a problem, I would guess the cabling would have to be accessed through your relative’s new ceiling, so probably best to get this sorted now.

If the cable is fully enclosed in 200mm insulation, that will reduce the current carrying capacity of the cable by much more than if the cable just makes contact with the top of the insulation. If there is a way to clip the cables to the underside of the floor joists, so they have air above them for the majority of the run to dissipate heat, that would have less effect. I think it is also permissible to make small notches in the joists, or even to put cables through holes drilled in the centreline of a joist, but again, I would advise involving the upstairs neighbour and a professional electrician before doing anything decisive!

Hope it all gets sorted for you,

Felix

Hello Felix24,

The Electrical cables in the floor void of the flat above are existing.

Depending upon their direction across the Kitchen area some are in holes drilled through the approximate centre of the joists and some that are routed along the run of the joists were just laying on the ceiling before it was pulled down - now just hanging below the joists until the insulation pushes them up to just under the upstairs flat floorboards.

The cables that will just be pushed upwards by the insulation will be laying on it and probably touching the under side of the floorboards and the cables that are routed through the centre of the joists will be completely enclosed by the insulation.

Any future access to the upstairs flat cables would still be from their home - taking up the floorboards that were lifted to carry out the most recent rewire but of course the insulation would be more than just a bit of a nuisence if a future Kitchen rewire was required.

My family member has informed the neighbour upstairs and they are very pleased to know that sound proofing insulation is being fitted because downstairs have 3 young children who can be very noisey - screaming when playing just like most young children.

Now that I have written wrong information to my family member and embarrassed myself I will probably stay out of any futher involvement.

Thanks to Members who have read this thread and to You and Member nicebutdim for your replies.

Chris

 

[littlespark]

You haven’t embarrassed yourself.

You’ve brought up what could be a problem…. Showing some extra thought needs to go into this rather than just “we’ll stuff it full of rock wool”

Heat dissipation is a problem…. Even some low temperature LED downlights, fitted into a ceiling still ask that insulation doesn’t cover the fitting.
(There’s no downlights going in this new kitchen ceiling, is there?)


The builder might take the hump, but they’re known for it.

Could the same sound deadening be obtained by solid slabs of insulation, fitted below the cables?

 

[nicebutdim]

Hello again,

The last thing that I wanted to do was to irritate you.

I did refer to what you wrote about there being regulations about this for new build properties with cable types / sizes and runs being designed to allow them to run through various Building materials including insulation without any detrimental effect on the installation.

I was just giving an opinion about insulation being fitted in existing Homes / Buildings on top of or around existing electrical cables.

Chris

There was no irritation on my part - I just thought you'd missed the point. The same regulations apply whether the installation is new or old, but it's not easy forcing other trades to inform themselves on issues affected by their work.

 

[oscar21]

Insulation doesnt cause cables to heat up, it just stops them dissipating the heat they produce. If a cable doesnt get warm in free air it wont get warm in insulation.

 

[chris murphy]

Insulation doesnt cause cables to heat up, it just stops them dissipating the heat they produce. If a cable doesnt get warm in free air it wont get warm in insulation.

Hello oscar21,

When I wrote about cables heating up I meant that IF a cable heated up that heat could not dissipate correctly if the cable was enclosed or contacting insulation.

I would have thought that as we know some domestic electrical installation cables definitely do heat up - for example those supplying sockets that are powering 3Kw fanned convector heaters - rockwool or fibreglass insulation completely enclosing those cables and preventing that heat from dissipating cannot be good for the long term condition of the cable insulation ?

As I am sure that we have all seen many homes have those types of Convector heaters - often remaining permanently plugged into the same socket rather than moved around the home`s rooms so the cables powering those sockets will be heating up regularly possibly for many years and where those cables are enclosed in insulation surely that cannot be O.K. ?

The Builders who are involved in my family members flat have said that when they are doing works in flats that involve sections of ceiling having large holes created such as when there are walls being removed or where ceilings are badly damaged / badly cracked they always suggest Soundproofing insulation is fitted.

After hearing what they said to my family member the wording sounded like they were trying to suggest that it was required by the Building Regulations which would have been totally misleading for an existing property / flat - unless I am guessing when ceilings have to be pulled down perhaps soundproofing insulation would then be a requirement of the Transfer of Sound regulations ?

I mention that because I do know that this type of Soundproofing is becoming more popular in refurbishments where enough dirty / dusty work is being carried out that pulling down ceilings is not seen as prohibitively messy for the property in terms of additional dust etc.

My comments on this thread and on any other Electrical matter / Electrical question are only my perceptions I would never try to actually argue or debate any technical point with Electricians on here.

I would never even attempt to answer a question about Electrics on here.

I originally joined the Forum many years ago to ask some Electrical questions about my own home and after receiving that help I decided to give back help to members who had posted threads asking questions about Heating systems that were not only electrically based [pipework queries / possible faults etc.] by responding to those types of questions.

Some years after that members were directed to post those types of questions on the UK Plumbers Forum so I have not been able to help any further on here but I have still been able to receive help with some of my questions such as on this thread.

Thanks to the Members who have replied to me and to those who have read this thread and my others.

Chris

EDIT: The questions that I referred to above that I had posted many years ago when I joined this excellent Forum about the Electrical installation in my home are no longer showing on the My Content list perhaps due to a previous Forum reorganisation ?