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Topic Title: No earth on lighting circuit
Topic Summary: what pir code
Created On: 24 January 2008 07:48 PM
Status: Post and Reply
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 24 January 2008 07:48 PM
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EGGO

Posts: 109
Joined: 14 June 2007

Hi lads

My 1st pir with this problem.

Downstairs lighting circuit has no earth, and the light switches are metalic.

What pir code should i use and can anyone recommend a solution without rewiring circuit.

Cheers

John
 24 January 2008 07:53 PM
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chris5

Posts: 57
Joined: 04 February 2006

Definately code 1 if metallic switches, think I'd go for rewiring the circuit
 24 January 2008 08:03 PM
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AMN

Posts: 644
Joined: 29 June 2007

Code 1, replace with plastic fittings asap until a cpc can be run in some how.
 24 January 2008 08:13 PM
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EGGO

Posts: 109
Joined: 14 June 2007

Hi Chris5

Thanks for your advice

Cheers john
 24 January 2008 08:31 PM
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EGGO

Posts: 109
Joined: 14 June 2007

Hi AMN

Thanks for your reply and temporary solution.

If they were to change the switches to plastic, would this satisfy reg 471-08-08, and in this case, is there still a requirement to earth the circuit.

My understanding is that all lighting circuits installed since (England last won the world cup)!!! should have a cpc.

Cheers John
 24 January 2008 08:41 PM
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AMN

Posts: 644
Joined: 29 June 2007

Yes you would still have to provide an earth, though at least by fitting plastic switches you are reducing the risk until this can be done. Ive had this quite a bit in the past and have used fittings with the screw covers, just to be sure. If your customer doesn't want the hassle of rewiring the whole circuit you may be able to slip a 4mm cpc down the conduit or channel if its got one and connect to an earth somewhere convenient.
 24 January 2008 08:45 PM
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goodrias

Posts: 59
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for your PIR you should note, not only is there no CPC, with metallic switches, but as there should also be a warning on the consumer unit. to warn consumers not to fit metallic units on these circuits,
 24 January 2008 08:49 PM
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AMN

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Yes just like the instructions that came with the metallic fittings saying 'these fittings must be earthed'. Say no more !
 24 January 2008 08:49 PM
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EGGO

Posts: 109
Joined: 14 June 2007

Hi Goodrias

Good Point

Thanks

john
 24 January 2008 09:04 PM
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goodrias

Posts: 59
Joined: 01 November 2004

i did a template for label sheets for this if you want it? , it was worded as per the electrical saftey councils guidance sheet on consumer unit changes with no cpcs on lighting
 24 January 2008 10:52 PM
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EGGO

Posts: 109
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cheers mate

my email address is Alarumsecurity@blueyonder.co.uk

thanks john
 25 January 2008 09:31 AM
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StevieP

Posts: 98
Joined: 19 December 2006

If your customer doesn't want the hassle of rewiring the whole circuit you may be able to slip a 4mm cpc down the conduit or channel if its got one and connect to an earth somewhere convenient.



Why 4mm2 ??
 25 January 2008 12:47 PM
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AMN

Posts: 644
Joined: 29 June 2007

Unless mechanically protected needs to be 4mm2. Unless you are going to run it in conduit all the way back to the MET or wherever else you are picking up an earth.
 25 January 2008 02:50 PM
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StevieP

Posts: 98
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Unless mechanically protected needs to be 4mm2.


Why ?
This is an earth to a back box
Reg No ?
 25 January 2008 03:58 PM
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AJJewsbury

Posts: 11784
Joined: 13 August 2003

Why ?
This is an earth to a back box
Reg No ?

Because it'll run outside of the box, not enclosed in a cable, conduit etc.

543-01-01.

- Andy.
 25 January 2008 05:30 PM
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ebee

Posts: 5814
Joined: 02 December 2004

"My understanding is that all lighting circuits installed since (England last won the world cup)!!! should have a cpc."

If you`re refering to football, it`s more like the last but one time we won it.

-------------------------
Regards,
Ebee (M I S P N)

Knotted cables cause Lumpy Lektrik
 28 January 2008 07:22 AM
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StevieP

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Thanks Andy

Steve
 28 January 2008 09:22 AM
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bobdenton

Posts: 225
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Originally posted by: EGGO

My understanding is that all lighting circuits installed since (England last won the world cup)!!! should have a cpc.



Cheers John



John, as you're doing a PIR rather than work on the circuit the considerations are slightly different.

If the circuit appears to have been installed in compliance with the regulations current at the time of installation (14th?) it's presumed to be safe. There's no obligation to upgrade to comply with the current regs. This would indicate a code 4 as a starting point. I don't suppose anyone would feel happy about that, having been trained in later editions of the regs. I'd look to see if there was an obvious shock risk in the event of fault, such as an unearthed metallic switch plate being within arms reach of an extraneous conductive part, and base any coding on that. Code 1 would be a bit difficult to justify, it was considered safe 45 years ago and has functioned safely since, so to give a code which would mean it was unsatisfactory for continued service would be a bit dramatic. I would go for Code 2, it requires improvement.

If that leaves you feeling uneasy, then it may be that you just don't know when it was installed, it may have been 10 years ago, then a Code 1 maybe.

Its strange that the date of installation should affect the coding when all that's changed is the date. It would'nt make any difference to the recommendations to the customer.
 28 January 2008 09:55 AM
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iansettle

Posts: 777
Joined: 20 September 2005

Originally posted by: EGGO

Hi AMN



Thanks for your reply and temporary solution.



If they were to change the switches to plastic, would this satisfy reg 471-08-08, and in this case, is there still a requirement to earth the circuit.



My understanding is that all lighting circuits installed since (England last won the world cup)!!! should have a cpc.



Cheers John


Last time England won the world cup was 2003!!!!! Cpc have been used before that.
 29 January 2008 07:08 PM
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Paul1966

Posts: 1538
Joined: 21 December 2004

Originally posted by: bobdenton
If the circuit appears to have been installed in compliance with the regulations current at the time of installation (14th?) it's presumed to be safe.


The 14th edition (1966) was the first to specify earths throughout every lighting circuit:

D.6 At every lighting point an earthing terminal shall be provided and connected to the earth-continuity conductor of the final sub-circuit.

D.7 An earthing terminal, connected to the earth-continuity conductor of the final sub-circuit, shall be provided at every lighting switch position unless this takes the form of an earthed metal box having a means of fixing the switch-plate in reliable electrical contact with the box.

NOTE.- Regulations D.6 and D.7 are applicable even where a point or switch position is intended, at the time of installation, for the attachment of an all-insulated accessory or fitting or a double-insulated fitting. They are intended to allow for any later substitution of an accessory or fitting which needs to be earthed.


However, metal switch plates on unearthed lighting circuits did not comply even before the 14th edition.

Regulation 403 outlined exposed metalwork which was not required to be earthed, the relevant clauses being:

(v) Metal boxes used with tough-rubber-sheathed or p.v.c.-sheathed wiring systems, if screened by non-conducting material


and

(ix) Lighting fittings using filament lamps installed in a room having a non-conducting floor, mounted at such a height that they cannot readily be touched and are out of reach of earthed metal.
IET » Wiring and the regulations » No earth on lighting circuit

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