What counts as clipped direct?

[esar]

Hi Everyone,

I'm planning on doing a DIY re-wire of the house I've just bought.
I'm working though the finer details of where and how the cables are going to be run and I've got a couple of questions:

Do cables run under the first floor floorboards that are laying on the ground floor ceiling count as clipped direct even if they're not actually clipped to anything (there's no insulation)?

On the ground floor where there is a suspended timber floor, the existing cables are just lying on the compacted earth. Is this acceptable and does it count as clipped direct? Or should I clip the replacements to the underside of the joists (again there's no insulation)?


thanks

stephen.

 

[wingcoax]

Ok upstairs as you can pull through in the future and as for downstairs, screw brackets to the joists to act as hangers or fit cable tray. This will not only remove the cables from vermin reach but make things a lot tidier.

 

[riveralt]

Just read the

'Electrician's Guide to the Building Regulations' page 28 item 2.3.1

The Onsite Guide page 43 item 7.1.(iii)

The IEE Wiring Regulations - Appendix 4 item 7.1

All your 'questions' will be answered

Alternatively call in an electrician - if you do not know what clipped direct means then I fear your knowledge may be too limited to carry out the work you are comtemplating.

Edited to include page/appendix references

 

[esar]

Ok upstairs as you can pull through in the future and as for downstairs, screw brackets to the joists to act as hangers or fit cable tray. This will not only remove the cables from vermin reach but make things a lot tidier.

Thanks, there aren't going to be many circuits under the ground floor (2 rings, 1 cooker) and the cables will almost never be together so the trays are sounding like overkill but I think the brackets could work well.

 

[ericmark]

The idea of clipping a cable to some other material is to remove heat. Not being clipped will mean less heat is removed since Reference Method 100# will allow normal ring main why would you want clipped direct?

I do question the use of Ali-Tube to BS 8436 as although the current ratting is higher clipping onto cable tray made of steel is OK but 90 deg C clipped to wood one wondered if the wood can take this temperature without charring?

I would not worry about a SWA cable laying on a compacted earth floor. I would not worry too much about Ali-tube but twin and earth is too open to rodent attack.

Although this is not the major problem. The real problem is what will your inspector accept and you can ask as much as you like on here but it is all up to guy inspecting.

I would say you need to make detailed plans so once passed there is no room for the inspector to interrupt what you have done as being different to what you said you were doing. He may accept a drawing on a fag packet but this does not help you latter when he refuses to pass what you thought had been agreed.

 

[esar]

Just read the 'Electrician's Guide to the Building Regulations' page 28 item 2.3.1

I don't have this but I've read the regulations themselves and they don't seem to cover it

The Onsite Guide page 43 item 7.1.(iii)

This one I have read but it doesn't seem to cover whether the "clipped" part of "clipped direct" actually means the cables need to be clipped to something. In fact as far as I can tell it never actually defines "clipped direct".

The IEE Wiring Regulations - Appendix 4 item 7.1

How much!
Surely these should be sold for the cost of duplication and/or free for download like the building regs?

All your 'questions' will be answered

The closest I've come to finding an answer is in 17th Edition IEE Wiring Regulations, Explained and Illustrated by Brian Scaddan where there's a nice diagram on page 93 but that doesn't really cover it either. I guess it's just considered to be too bloody obvious to bother putting in the books and the sort of thing that a pro picks up on an apprenticeship.

Alternatively call in an electrician - if you do not know what clipped direct means then I fear your knowledge may be too limited to carry out the work you are comtemplating.

I'm not worried about creating a safe installation, all the books cover the design of the circuits very well, the only bit I'm slightly worried about is making an assumption that the word "clipped" doesn't actually mean clipped and having to reinstall some of the cables when it's inspected.

 

[esar]

The idea of clipping a cable to some other material is to remove heat. Not being clipped will mean less heat is removed since Reference Method 100# will allow normal ring main why would you want clipped direct?

Cheers, that's a damn good point, I guess I'm not seeing the wood for the trees worrying about whether it counts as clipped direct when I could just pretend it's packed in insulation and it's still good enough.

 

[GaryMo]

I take it that some of these ground floor cables are within capping and buried within the wall which rise to sockets and a cooker switch? That'll count as clipped direct.
You really ought to clip these cables where possible to keep them off the ground though.

Same applies to first floor cabling unless any runs through thermal insulation.
With regards to clipping the cables, you'll find that most electricians won't clip cables as directed due to accessibility issues and not wanting to rip up every other floorboard.

The reference method to note and design in accordance with will be the worst case scenario.

 

[riveralt]

Just read the 'Electrician's Guide to the Building Regulations' page 28 item 2.3.1

I don't have this but I've read the regulations themselves and they don't seem to cover it

So you are aware of your responsibilities with respect to
Approved document A
Approved document B
Approved document C
Approved document E
Approved document F
Approved documents L1A and L1B
Approved document M
and of course the big mama Approved document P.

Guidance note 3 would be handy as well.

I haven't read this particular Scadden book so I don't know whether the tables he provides cover all the design eventualities.

If you feel confident enough to tackle this job then access to the Electricians Guide to the building regulations would go some way to ensure that you tick many of the boxes and may also go some way to satisfy your Local Authorities Building Control officer.

]
The IEE Wiring Regulations - Appendix 4 item 7.1

How much!
Surely these should be sold for the cost of duplication and/or free for download like the building regs?

Rather than pay out for BS7671 download appendix 4 here

http://www.voltimum.co.uk/news/11219/s/Appendix-4-of-BS-7671.html

 

[esar]

Just read the 'Electrician's Guide to the Building Regulations' page 28 item 2.3.1

I don't have this but I've read the regulations themselves and they don't seem to cover it

So you are aware of your responsibilities with respect to
Approved document A
Approved document B
Approved document C
Approved document E
Approved document F
Approved documents L1A and L1B
Approved document M
and of course the big mama Approved document P.

Probably not exhaustively but I think I've got most of the important stuff covered, though as I'm only re-wiring a 1930's semi I believe a lot of it isn't relevant:

A: Chases, recesses and the like: got it covered
B: I'm adding mains powered smoke alarms, not doing anything that could effect propagation of a fire
C: Already got other issues here
E: It doesn't have any to start with and I won't be making it worse
F: I'm not going to be doing anything to effect this
L1A: It's not a new build
L1B: energy efficient lights, nice...
M: I believe I can ignore this (socket height, etc.)
P: Doesn't actually seem to say all that much

Guidance note 3 would be handy as well.

I have Practical Guide to Inspection, Testing and Certification of Electrical Installations by Christopher Kitcher which seems to be a nice step by step guide to doing installation testing. I'll be hiring an all in one installation tester for a week and testing everything before building control's spark comes to do it again.

I haven't read this particular Scadden book so I don't know whether the tables he provides cover all the design eventualities.

Probably not, but then what I'm doing is pretty basic. Sockets, lights, cooker, smoke alarms and sub-main to garage all in a 1930's semi with solid walls, suspended timber floors and no insulation at all except in the loft.

If you feel confident enough to tackle this job then access to the Electricians Guide to the building regulations would go some way to ensure that you tick many of the boxes and may also go some way to satisfy your Local Authorities Building Control officer.

So far it doesn't sound like I'll have much contact with him at all, it seems to be a case of send him a building notice and £150 (done), later I notify him that I've finished first fix and he sends contract spark to have a look, I then finish up and spark comes back to test. Finally I get a completion certificate (I hope ).

]
The IEE Wiring Regulations - Appendix 4 item 7.1

How much!
Surely these should be sold for the cost of duplication and/or free for download like the building regs?

Rather than pay out for BS7671 download appendix 4 here

http://www.voltimum.co.uk/news/11219/s/Appendix-4-of-BS-7671.html[/QUOTE]


Thanks that looks useful.

 

[riveralt]

Good Luck

 

[ban-all-sheds]

Just read the 'Electrician's Guide to the Building Regulations' page 28 item 2.3.1

I don't have this

You really should.

but I've read the regulations themselves and they don't seem to cover it

But you don't have a copy of BS 7671 - where have you read it?

The IEE Wiring Regulations - Appendix 4 item 7.1

How much!

Trivial in comparison to the cost of your refurb, and less than what you'll spend on a takeaways whilst you're doing it.

Surely these should be sold for the cost of duplication and/or free for download like the building regs?

Then how would the activities of the British Standards Institute be funded?

Rather than pay out for BS7671 download appendix 4 here

http://www.voltimum.co.uk/news/11219/s/Appendix-4-of-BS-7671.html[/QUOTE]
Thanks that looks useful.

And in the download you'll see a drawing of Reference Method C....

 

[ban-all-sheds]

The idea of clipping a cable to some other material is to remove heat. Not being clipped will mean less heat is removed.

So why are ratings higher for Methods E, F & G than Method C?

 

[esar]

Just read the 'Electrician's Guide to the Building Regulations' page 28 item 2.3.1

I don't have this

You really should.

but I've read the regulations themselves and they don't seem to cover it

But you don't have a copy of BS 7671 - where have you read it?

I'm assuming (possibly incorrectly) from the title that it's a guide to the building regulations as found here:
http://www.planningportal.gov.uk/wales/professionals/buildingregs/

which is where I've been doing my reading

The IEE Wiring Regulations - Appendix 4 item 7.1

How much!

Trivial in comparison to the cost of your refurb, and less than what you'll spend on a takeaways whilst you're doing it.

Surely these should be sold for the cost of duplication and/or free for download like the building regs?

Then how would the activities of the British Standards Institute be funded?

Taxes?

Personally I'm of the opinion that if we're required by law to follow a set of rules, we shouldn't have to pay to read those rules. At least we shouldn't have to pay more than cost of duplication.

Rather than pay out for BS7671 download appendix 4 here

http://www.voltimum.co.uk/news/11219/s/Appendix-4-of-BS-7671.html[/QUOTE]
Thanks that looks useful.

And in the download you'll see a drawing of Reference Method C....

Yep, and still not a clip in sight

That's really the only thing that's been confusing me, why is the word clipped there? does it actually have to be clipped, with a clip? There seems to be a lot of evidence to suggest it doesn't, it just needs to be in contact with a non insulating surface, but if that's the case then why is the word "clipped" there?

 

[ColJack]

clipped direct = stuck to, sitting on or buried in a surface that is reasonably thermally conductive ( for the majority of the cables length ).

as the "stuck to" surface can be vertical or even upside down, the use of mechanical fixings spaced at intervals along the cables length may be required.