Reference method ?

[steptoe]

NO PROBS MACCA,

but u have at least 2 forms of ref there if not 3,

I dont keep my book beside me so cant quote them but no doubt somewone will before tomoz nite.

thats why I ask you the Q.

nothing is ever as plain as it seems if you are putting your name to it you need to be legally certain.

 

[SPECIAL LOCATION]

I would go for

ref method 103,

(pg 52 OSG table 7.2)

"surrounded in thermal insulation"

at the point where it passes though to the CU, isolator switch & down to shower, it will be "surrounded by insulation"!

Also if you leave it on the top of the Insulation...... someone may come along later and chuck something else over it!

 

[davetheglitz]

What about cable de-rating when surrounded by insulation? If I remember correctly the cable rating goes down to half if greater than 0.5m is covered in insulation. To my mind having the cable above the insulation makes far more sense regardles of what is quoted as a referenceing method.

 

[SPECIAL LOCATION]

What about cable de-rating when surrounded by insulation? If I remember correctly the cable rating goes down to half if greater than 0.5m is covered in insulation. To my mind having the cable above the insulation makes far more sense regardles of what is quoted as a referenceing method.

morning Dave

De-rating indeed does apply!

but I look at the probable risks of what may happen to the cable during its reasonable working life...

IHMO if the cable is not clipped to something..

you have no way of knowing its not going to get covered or buried by either..

1) someone else moving the insulation around..(say plumber putting pipes though, T.V. aerial installation Eng', etc...)

2) someone has the bright idea to board the loft, (all or part) sticks a few more beams across.. squashed the insulation around a bit... and puts there B&Q T&G chipboard across the top...

3) customer decides to chuck them off-cuts of carpet up the loft when they have new carpet fitted downstairs..

All examples of what does happen in the real world...

went back to a job this week that I rewired back in Feb/March..

they were still due to have a new bathroom suit fitted tiled etc..

and were now ready for final fix of some bathroom electric stuff..

had to go in the loft to the transformer/timer for the 12v extractor fan..

& the whole loft now boarded! nice new springy hatch door with fold-out ladder... all the cables now completely buried & enclosed!

back to inst methods..

To my understanding if it is clipped to something ... One side of the cable can NOT get buried..

& this appears so by the guidance on pgs 52, 53 OSG?

e.g.

the little picture of method 100 has a the left-hand cable very close to the top of the insulation... but its still no different then the middle cable resting on the plasterboard.. which IMHO is more buried????

I'd probably grab a few batons. nail em between some roof supports and clip my cable up above the insulation... [clipped direct method C: 10mm 64A]

OR maybe...

stuff some conduit.. (or maybe flat ducting).. and put the cable under neath the insulation.. so it cant get any more buried than it already is! [enclosed in conduit in insulation method A: 10mm 44A]

OR...

Pull some insulation back and take it around the edge of the loft where no insulation..

I understand there is normally some small gap at the edges to allow the ventilation from under the eaves to come through... stop dry-rot or condensation buildup in the loft?

First option most likely for me, rather than leaving loose across insulation?

? :| ?:|

 

[maccarooni]

thank you all for your inputs.

Let me perhaps explain a little more.

the reason its on top of the insulation is that the shower is temporary ( max 6 mths ) having an extension built and loft conversion done. Bath had to be taken out as part of works being done. So in order to wash stud wall erected tiled and shower enclosre fitted, electric shower installed. hunky dory...applied 2 weeks ago to nic for assessment.. No probs,,,will be at least 8 weeks for assessment. wrong. Hello Mr macca, I'm from niceic, We have your application, would you be available next Monday 13/10 for assessment as we have another in the area.....SH** of course yes sir and all that....

Panic stations for the rest of the day ( Also see other posts regarding litrature for assessments. ) Any way up to my neck in work. haven't got many options for assessments so would like to use NEW circuit..ie shower..

Trying to make sure that i have filled out cert properly but couldn't find ref for what i have described as installation. I will be using ref method C and 101but didnt want to not state an obvious method. Hope this clears up some unanswered questions.

Many thanks again

Macca

Guiness DrinkGuiness DrinkGuiness DrinkGuiness Drink

I'm gonna have 4 tonite... :^O

 

[davetheglitz]

Thanks SL. Good advice as always.

In our area there are a lot of grants to fit loft insulation and the contractors bury everything in sight by going across the joists. Quite scary - even with crawler boards - you don't know what is underneath. Point is these contractors are burying shower cables willy nilly. Why aren't we getting more fires in houses? Have there been any instances of problems with this - or are our standards so high that the actual risk is infinitessimal?

A touch of devils advocate here - but in the event of a fire who would be responsible? I take SL's point that the best option would be to make sure that cable is clipped above any place where insulation might be - but this can't be retrospective - and in the event of difficult access I think I would err on laying the cable unclipped across the insulation.

Another viewpoint for lofts with difficult access - in the event of a cable failure it would be possible to pull a new cable throught from underneath in the event of a breakdown if the cable wasn't clipped to anything.

Other advice is to run all cables to the edge of the loft and clip to battens there so access is maintained in the event of a loft conversion.

Bit of a brain dump - but would be interested in any opinions - as I haven't made my mind up which is right or wrong.

Cheers

Dave

 

[SPECIAL LOCATION]

I agree entirely with what you say there Dave

IMHO

I just think this is one of those areas where everyone can be right & wrong..

because there is no such thing as a standard loft..

and every loft would need to be assessed as to its relative merits..

As you say if it is so small & unaccessible that the risk of cables being disturbed or buried later, then any possibly hazard is negligible!!

But if its a nice big, tall, wide loft hatch job..

then it could be considered quite reasonable that a competent person should consider it likely that cables need a bit better fixing or protection!?

I think its just a matter of being aware of realist possible hazards...

then apply common sense & judgement based on each individual situation!

there is NO one-size-fits-all correct answer...

but you do need to be aware of the various limitations / considerations for compliance with the regs.

and each one of us as sparks just need to be sure we can sign our certs with a clear conscience.

 

[SPECIAL LOCATION]

thank you all for your inputs.. Hello Mr macca, I'm from niceic, We have your application, would you be available next Monday 13/10 for assessment as we have another in the area.....SH** of course yes sir and all that....

Panic stations for the rest of the day ............Macca

Guiness DrinkGuiness DrinkGuiness DrinkGuiness Drink

I'm gonna have 4 tonite... :^O

Good luck with the assesment Macca!

I shall have a few for you as well!

Guiness DrinkGuiness DrinkGuiness DrinkGuiness DrinkGuiness Drink:^O

 

[kme]

Just to add.......

IMO, an unclipped cable in free air is not an acceptable installation method. As SL suggested - battens to clip it to, trunking/conduit......

I wouldn`t show that one, if it were me, m8. Sorry...

 

[a1]

Just to add.......IMO, an unclipped cable in free air is not an acceptable installation method. As SL suggested - battens to clip it to, trunking/conduit......

I wouldn`t show that one, if it were me, m8. Sorry...

I mentioned this to the lecturer when I was doing my 17th Edition. He said that would be a NO, because the heat can't dissipiate from the cables. :_|

 

[SPECIAL LOCATION]

IMO, an unclipped cable in free air is not an acceptable installation method. As SL suggested - battens to clip it to, trunking/conduit......

I mentioned this to the lecturer when I was doing my 17th Edition. He said that would be a NO, because the heat can't dissipiate from the cables. :_|

erm? so what about Table 7.2... OSG... page 52?

what does your lecturer suggest about that?

Inst method 'A':

enclosed in conduit in an insulated wall..

{same concept as conduit in insulated ceiling?}

10mm C.S.A. rating 44amps...

44a X 230v = 10120watts...

me thinks would be ok up to a 10kw shower?

volt drop & length permitting?

 

[kme]

erm? so what about Table 7.2... OSG... page 52?what does your lecture suggest about that?

Inst method 'A':

enclosed in conduit in an insulated wall..

{same concept as conduit in insulated ceiling?}

10mm C.S.A. rating 44amps...

I did say unclipped in free air - not the same as in conduit.

44a X 230v = 10120watts...

me thinks would be ok up to a 10kw shower?

volt drop & length permitting?

Applaud Smiley

 

[maccarooni]

Again thank you all for all replies.

So,to make things easier for myself i have removed the said offending insulation for the run where the cable runs. Now some might say ,,,King hell,,,, thats a bit drastic. Well yes and no. Yes as i spent a hot afternoon in the loft, and no as ( previous posts told of extension/ loft conversion ) the insulation will have to be taken out soon any way. Now this shower in not permanent in its position at the moment and will be moved to its new room when possible . Generally when installing cables in lofts i do stick to eaves where possible or clipped up on a batten above the insulation, thanks Spec for you good wishes and i shall tell all tomorrow evening. I have never been through an assessment and have nightmares of inspector climbing in loft and shouting at me ( TUT TUT TUT Macca you know thats not right LOL )although, i have worked for an NIC registered company for 7 yrs.

Many thanks all

Macca

Guiness DrinkGuiness DrinkGuiness Drink

 

[Apache]

Good luck with it mate

 

[maccarooni]

thanks apache

Guiness DrinkGuiness DrinkGuiness Drink

 

[maccarooni]

Guiness DrinkGuiness DrinkGuiness Drink

Well Assessor came and went. Not half as bad as i had thought it was going to be. He didn't even get in the loft LOL. gave me a compliance as DI, Got to wait for head office to ok it and could be all registered in 2 weeks. Nerve wracking for the first 10 min or so. He knew i was nervous but put me at ease. Very helpful with my Qs to him. Hopefully will have a fitful sleep tonight. ( well 4 1/2 hrs anyway. )

Macca

 

[SPECIAL LOCATION]

Guiness DrinkGuiness DrinkGuiness DrinkWell Assessor came and went. Not half as bad as i had thought it was going to be. He didn't even get in the loft LOL. gave me a compliance as DI, Got to wait for head office to ok it and could be all registered in 2 weeks. Nerve wracking for the first 10 min or so. He knew i was nervous but put me at ease. Very helpful with my Qs to him. Hopefully will have a fitful sleep tonight. ( well 4 1/2 hrs anyway. )

Macca

WELL DONE M8!

Looks like it time for another celebration!!Guiness Drink

 

[Apache]

Aye - well done. We'll have to get some more beer in

 

[a1]

I say - Well done.

 

[a1]

Applaud Smiley