Covering electrical wiring for lighting circuits with loft insulation ?

[chris murphy]

"Hello All",


Could I get the Opinions of some of the Electrical Professionals Please regarding covering Electrical Wiring for Lighting Circuits with Loft Insulation - Here are some details regarding why I am asking - And although I THINK that I am correct in stating that this should NOT be done - the `Real World Practicalities` that I have been Reminded about:


I am advising a Relative about some Energy Efficiency Measures for their recently purchased Home - the most Obvious / Effective being to have the Loft Insulation Topped Up to 270mm thickness of Fibre Glass Loft Insulation.

This has raised the Question about the Lighting Wiring being Covered by the Loft Insulation - Which I think that I KNOW [?] should NOT be done - ?

I believe that I would have known many Years ago that this should NOT be done because of the possible Overheating of the Wiring - But I was `Reminded` by a representative from the Company who will be Installing the Loft Insulation that in almost ALL Lofts the Lighting Wiring CANNOT be lifted up to accommodate the Loft Insulation underneath.

He told Me that IF I was Correct in stating that the Wiring should NOT be covered EVERY Home that they Insulated would have to be Rewired for the Lighting Circuits - To Allow enough `Slack` in the Wiring to Install the Insulation underneath - Which obviously is NEVER done ! - And He stated that He would NOT want the Insulation Operatives to be `Pulling Cables About` in any case - Because of possible `Loose Wires`.

I have looked Online about Installation Methods for Loft Insulation and did find the comment about NOT Insulating over Electrical Wiring - BUT - As the Insulation Company representative stated this is NEVER adhered to by them or any other Loft Insulation Company that He has worked for.

And that this `Requirement` would STOP People from having their Homes Insulated because VER FEW People would be prepared to have an Electrician Rewire the Lighting Circuits to accommodate the Loft Insulation - ALSO - a very large percentage of the Company`s work is carried out under Grants for Home Energy Efficiency and these Homes would NOT be Insulated IF the Electrical Wiring had to be Redone - Thousands of Properties !


Obviously I realise [If this is correct ?] that with the use of `Low Wattage` / High Efficiency Lightbulbs [Lamps] there is not so much `Draw` through the Lighting Cables - and I assume that this means there is much less possibility of a Overheat Situation - ?? - But I was told that NOT Covering the Electrical Cables with Loft Insulation has NEVER been adhered to - Regardless of the Wattage Lightbulbs that were in use [NEVER even considered].

He / the Insulation Operatives were aware of the need for `Boxes` to enclose Recessed Lights prior to Loft Insulation being fitted.


I was told by the Insulation Company Representative that He could not remember this `Issue` EVER being brought to His attention and that He has worked for 3 Insulation Companies who have probably Insulated `Hundreds of Thousands` of Homes between them !

I would really appreciate the Professional Opinion of some Members - And I would ask Are the Electrical Cables in YOUR Lofts covered by Loft Insulation ?


"Sorry" to have written such a long Post about this - But I wanted to explain the situation correctly.


Chris

 

[trev]

What would be better for us sparks would be installation of kingspan or something similar in the rafters. That way we wouldn't have to worry so much about it.

 

[chris murphy]

the o/p might want to have a look at 523.7 BRB and table 52.2 BRB which is as 6B..appendix 6 p(125) in the on site guide......

"Hello GLENSPARK",

Thanks for Posting the References that You noted for Me - I WILL endeavour to research those - As I am Interested in finding out more regarding what I enquired about - Although I think that the `Simple Explanations` that I received have put My mind at rest regarding My Relative`s Home - forthcoming Loft Insulation.

As You may have noticed from My various Posts I am NOT an Electrician - I am a Heating Engineer - When I completed Courses [Years ago] on the ACOPS Electrical Scheme - JUST to be confident of being `Electrically Safe` when working on Gas Appliances etc. - And the Course and Assessment for the CORGI Defined Scope in Electrical Installation etc. I had access to [and owned a couple] Various Electrical Regulation Manuals -Mainly from the Institute of Electrical Engineers - [now called IET ?] - and obviously at the College I would have been able to Refer to ANY Document - British Standards etc. that was relevant to the Course and `Exams` / Assessments.

NOW - especially as I do NOT carry out My own Electrical Wiring for Heating Systems etc. I do NOT have these Reference Manuals / British standards to refer to - Because I do NOT need to - Otherwise I would have ALL that I would ever need as a matter of course - As I am sure You and your fellow Electrical Professionals do have.

I have a Multitude of Reference Documents / Manuals and British Standards relating to Gas Utilisation / Gas Safety - Water Regulations - Health & Hygiene Regulations - and many more - As with Yourself I sometimes need to refer to an actual Regulation or British Standard / CE Mark / Details - Because these ARE relevant to My `Scope of Works`.

Thank You again for the references to these `Informative` / Regulatory Paragraphs - which I hope that I am correct in thinking that are in the Institute of Electrical Engineers [IET]Onsite Guide ?? - Hopefully I may be able to find these Online ?

Regards,


Chris

 

[telectrix]

What would be better for us sparks would be installation of kingspan or something similar in the rafters. That way we wouldn't have to worry so much about it.

exactly what i think. the problem is cost. a 8 x 4 sheet of kingspan is around £35. and the time taken to cut and install it. you can teach a monkey to lay fibreglass but sharp tools are needed for kingspan

 

[GLENNSPARK]

"Hello GLENSPARK",

Thanks for Posting the References that You noted for Me - I WILL endeavour to research those - As I am Interested in finding out more regarding what I enquired about - Although I think that the `Simple Explanations` that I received have put My mind at rest regarding My Relative`s Home - forthcoming Loft Insulation.

As You may have noticed from My various Posts I am NOT an Electrician - I am a Heating Engineer - When I completed Courses [Years ago] on the ACOPS Electrical Scheme - JUST to be confident of being `Electrically Safe` when working on Gas Appliances etc. - And the Course and Assessment for the CORGI Defined Scope in Electrical Installation etc. I had access to [and owned a couple] Various Electrical Regulation Manuals -Mainly from the Institute of Electrical Engineers - [now called IET ?] - and obviously at the College I would have been able to Refer to ANY Document - British Standards etc. that was relevant to the Course and `Exams` / Assessments.

NOW - especially as I do NOT carry out My own Electrical Wiring for Heating Systems etc. I do NOT have these Reference Manuals / British standards to refer to - Because I do NOT need to - Otherwise I would have ALL that I would ever need as a matter of course - As I am sure You and your fellow Electrical Professionals do have.

I have a Multitude of Reference Documents / Manuals and British Standards relating to Gas Utilisation / Gas Safety - Water Regulations - Health & Hygiene Regulations - and many more - As with Yourself I sometimes need to refer to an actual Regulation or British Standard / CE Mark / Details - Because these ARE relevant to My `Scope of Works`.

Thank You again for the references to these `Informative` / Regulatory Paragraphs - which I hope that I am correct in thinking that are in the Institute of Electrical Engineers [IET]Onsite Guide ?? - Hopefully I may be able to find these Online ?

Regards,


Chris

Well firstly thanks chris. i am still (trying) to learn this trade myself and consider myself green. As far as the OSG and the BRB/BGB are concerned its a case of hands in wallet i`m afraid.......

 

[chris murphy]

"Hello" ,

Insulating between the Rafters in a Home where the Roof Space is NOT going to be converted into Living Accommodation would NOT be a suitable Method of Insulating to prevent Heat Loss - The Inherent Ventilation of a Roof Space - Some Intentional and some `Adventitious`/ Naturally Occurring / Draughts means that even with Insulation between the Rafters the `Air Space` would be nearly as COLD as Outside Air - even with the Heat Gain from the Home - which would largely be dissipated by the Cold Air from outside.

In Fact I have experience of exactly this `Error of Judgment` from a Client who thought that He would Insulate between the Rafters of His Home prior to then wanting to have a Gas Boiler Installed in the Roof Space - This was NOT suitable - as the Roof Space was still Classified as `Equivalent to Outside Air` regarding Ventilation and Air Temperature.

I am sure that You have all come across Gas Boilers Installed in Roof Spaces - BUT - There are MANY Regulations and Requirements to be fulfilled to enable such Installations to be CORRECT - And the `Outside Air Temperature` Classification means that VERY FEW are `Correctly Installed` - Especially with a view to Installing a High Efficiency Condensing Gas Boiler in a Roof Space.

Unless an Enclosure is Designed and a Boiler that does NOT require Compartment Ventilation is Installed - Installing a Gas Boiler in a Roof Space is NOT to be Recommended - Even doing this there are MANY Regulations to be adhered to regarding Gas Safety / Isolation / Safe Access to the Boiler and Safe Working Platform etc. - A Boiler should NEVER be Installed in an `Open Area` of a Roof Space.

JUST the Simple Requirement of having to Install a Frost Thermostat - which would KEEP causing the Boiler to Fire Up because of the Roof Space Air Temperature would negate any Energy Efficiency of the `High Efficiency` Boiler - And exhibit the `Coldness` of the Roof Space when Insulated between the Rafters.


"Sorry" that I went into FAR TOO MUCH DETAIL - Just to state that Insulating between the Rafters is NOT a suitable Method of Insulating for Heat Loss from the Home - The Details about the Gas Boiler Installation were to `Illustrate` My point.


Chris - Heating Engineer / Gas Installer

 

[chris murphy]

Well firstly thanks chris. i am still (trying) to learn this trade myself and consider myself green. As far as the OSG and the BRB/BGB are concerned its a case of hands in wallet i`m afraid.......

"Hello and Thanks again GLENSPARK",

I thought that I probably would NOT be able to find those references Online - Just as almost ALL of My Professions Reference Material is Copyrighted and unavailable Online - Especially British Standards - An exception to this is the Gas Regulations which are available Online.

British Standards can Cost Hundreds of Pounds !- with even 6 Page Documents costing up to £50.00 !

I realise that we would be paying for the Research that went into formulating these Documents - BUT - As the People who should be putting the Standards into practice in conjunction with relevant Regulations i feel that they should be More Readily Available - As HAS now happened with GasSafe making British Standards Documents available to Registered Gas Installers at `Bundle Prices` on a Subscription Basis - But still quite a Cost to the Self Employed Engineer / Installer.

Thanks Again for your Reply - "Good Luck in your Electrical Career".

Chris

 

[GLENNSPARK]

So what do you think of copanies such as "renotherm" and the like that use a spray on insulation for between the rafters Chris?

 

[GLENNSPARK]

"Hello and Thanks again GLENSPARK",

I thought that I probably would NOT be able to find those references Online - Just as almost ALL of My Professions Reference Material is Copyrighted and unavailable Online - Especially British Standards - An exception to this is the Gas Regulations which are available Online.

British Standards can Cost Hundreds of Pounds !- with even 6 Page Documents costing up to £50.00 !

I realise that we would be paying for the Research that went into formulating these Documents - BUT - As the People who should be putting the Standards into practice in conjunction with relevant Regulations i feel that they should be More Readily Available - As HAS now happened with GasSafe making British Standards Documents available to Registered Gas Installers at `Bundle Prices` on a Subscription Basis - But still quite a Cost to the Self Employed Engineer / Installer.

Thanks Again for your Reply - "Good Luck in your Electrical Career".

Chris

Thank you Chris.
All the best.
Glenn.

 

[GaryM]

Just as almost ALL of My Professions Reference Material is Copyrighted and unavailable Online - Especially British Standards

If you look hard enough you will find and not via torrents etc.
I joined an online library (Manchester) and have access to British Standard which can be viewed and saved though they are encrypted. Well for a short time anyway
However, BS7671 isn't available for download in that particular way.

 

[chris murphy]

So what do you think of copanies such as "renotherm" and the like that use a spray on insulation for between the rafters Chris?

"Hello GLENSPARK",

The main comment that I made which renders Insulating only between the Rafters NOT siutable to Prevent Heat Loss is that the Roof Space Ventilation - Both Purpose Provided / Roof Vents Installed and /OR the Existing `Adventitious Ventilation` from Gaps at the bottom of the Tiles / Slates or from the Soffit causes the Roof Space to have an Air Temperature close to the Outside Air Temperature.

You would still Lose almost the same amount of Heat INTO this Roof Space - which is classified as `Equivilent to Outside Air` regarding the Temperature and Air Changes - for example If calculations for taking Combustion Air for a Gas Appliance from the Roof Space area are carried out - It was sometimes allowable to take Combustion Ventilation for Gas Appliances from Roof Spaces - BUT - Now that High Efficiency Condensing Boilers must be Installed this practice is all but Redundant.

IF Roof Ventilation is present OR it is obvious that `Adventitious Ventilation` is present - Apart from NOT wanting the Roof Ventilation Blocked Off - The Installation of Sheet Material Insulation OR Spraying Insulation between the Rafters could seriously compromise the Ventilation of the Roof Space - Leading to a `Stale Air` situation where condensation causes ROT to appear on the Roof Timbers.

BUT the MAIN reason for NOT Insulating just between the Rafters - leaving a Well Ventilated Roof Space is because the HEAT from the Home will still be LOST INTO the Roof Space.


Chris

 

[chris murphy]

If you look hard enough you will find and not via torrents etc.
I joined an online library (Manchester) and have access to British Standard which can be viewed and saved though they are encrypted. Well for a short time anyway
However, BS7671 isn't available for download in that particular way.

"Hello GaryM",

Thanks for your reply - I may look for an Online Library which might be useful for ANY future Reference on MANY subjects - Thanks for the suggestion.

Chris

 

[Robinson]

Cable Is King ! Agreed with Amp. Check that In of MCB is < you should go wrong. If had done already as home owner i would consider a PIR to clarify these aspects of installation.

 

[Amp David]

Don't see where this is going now. At first thought it was a genuine question. Surely there are enough answers that confirm the worries given by the OP?

 

[GLENNSPARK]

"Hello GLENSPARK",

The main comment that I made which renders Insulating only between the Rafters NOT siutable to Prevent Heat Loss is that the Roof Space Ventilation - Both Purpose Provided / Roof Vents Installed and /OR the Existing `Adventitious Ventilation` from Gaps at the bottom of the Tiles / Slates or from the Soffit causes the Roof Space to have an Air Temperature close to the Outside Air Temperature.

You would still Lose almost the same amount of Heat INTO this Roof Space - which is classified as `Equivilent to Outside Air` regarding the Temperature and Air Changes - for example If calculations for taking Combustion Air for a Gas Appliance from the Roof Space area are carried out - It was sometimes allowable to take Combustion Ventilation for Gas Appliances from Roof Spaces - BUT - Now that High Efficiency Condensing Boilers must be Installed this practice is all but Redundant.

IF Roof Ventilation is present OR it is obvious that `Adventitious Ventilation` is present - Apart from NOT wanting the Roof Ventilation Blocked Off - The Installation of Sheet Material Insulation OR Spraying Insulation between the Rafters could seriously compromise the Ventilation of the Roof Space - Leading to a `Stale Air` situation where condensation causes ROT to appear on the Roof Timbers.

BUT the MAIN reason for NOT Insulating just between the Rafters - leaving a Well Ventilated Roof Space is because the HEAT from the Home will still be LOST INTO the Roof Space.


Chris

so..... all in all Chris such enterprises are a con...?

 

[chris murphy]

Don't see where this is going now. At first thought it was a genuine question. Surely there are enough answers that confirm the worries given by the OP?

"Hello Amp David",


I can assure You that it WAS a Genuine Question - From Me the Original Poster - I don`t know what You are referring to regarding `At first I thought it was a genuine question` ??

IF You are alluding to My Replies to GLENSPARK - Which obviously are `Off Subject` - I was simply Replying to Him to be Courteous - As I hope I would Reply to anyone who addressed ME Directly.

I obviously cannot comment IF You have been irritated by other Members Posting comments on My original Question - or on the responses to that.

In an earlier Post I stated that I had received a couple of Simple Explanations which `put My mind at rest regarding My Relatives Loft Insulation Job` - words to that effect - this comment was to signify that I had all the Information that I needed in Answer to My Question.

One of those Good Answers was from You - "Thank You very much again" for that.

I wanted to respond to your comment to try and find out what you meant ?

Regards,

Chris