Clearances for wiring in ceiling cavities

[Daniel Morgan]

Hello,

The Administrator has asked me to start a thread regarding my question "Is this a new regulation?" from post #6 in this thread, http://www.renovateforum.com/f195/installing-smoke-detector-102722/#post874098

The house involved was a new building as one of two on the block built in 2002, a certificate of electrical safety has been provided to the Administrator for verification as I do not wish the details to be made public.

As a builder, to have it pointed out that the wires must have the ability to deflect 50mm becomes impossible in this situation with 38mm battens, hence the question.

The simple mechanical solution to me is to just use two 35mm ribbon battens to create a 70mm cavity.

Whether it requires additional protection from an RCD is out of my hands, don't know, don't need to know really.

[chalkyt]

Hi Daniel
Sorry to frighten you. We were getting a bit off the track as the discussion started getting into "the rules" which were best debated elsewhere. Your situation may well have been o.k. prior to the current AS3000 (2007 version) which now requires the 50mm movement, mechanical protection or RCD protection. Unfortunately I don't have the previous AS3000 (2000 version),so I really can't comment. From your photo and description it sounded as though your work was prior to 2007, which you have indicated above, so all may be well as rule changes and amendments aren't retrospective. You will find that currently lighting circuits need RCD protection and in most cases the smoke detectors are part of that circuit. If that is so, the 50mm movement issue is covered by having an RCD even if you only have 38mm battens. From your photo and description, it looks as though connecting the lighting CB to the RCD would make it compliant with the current "rules" anyway. Happy building! :)

[Daniel Morgan]

Hello Chalkyt, thank you for the reply.


Sorry to frighten you.No you haven't frightened me, but reading your reply raised the question as my buildings could not provide the 50mm clearance of which you spoke.The fact that I had to explain and post pics of the construction method so the sparkies could understand was unfortunate.


You will find that currently lighting circuits need RCD protection and in most cases the smoke detectors are part of that circuit. If that is so, the 50mm movement issue is covered by having an RCD even if you only have 38mm battens. From your photo and description, it looks as though connecting the lighting CB to the RCD would make it compliant with the current "rules" anyway.

The RCD on lighting circuits is something I had noticed with newer installations, but wasn't aware that this was the escape clause for a reduction in clearance. Putting thicker battens in would have achieved the 50mm space required by your post #5 here, http://www.renovateforum.com/f195/installing-smoke-detector-102722/ There was no mention of escape clauses prior to that.

That thread has been raped and pillaged now so a bit hard to keep with it all.

The difficulty with all this stuff is that it is automatically assumed that you are unlicensed and derogatorily referred to as DIY , any sparkie that does his own work is DIY.

My question concerned how I could make it better/easier to be compliant, from the builders point of view.

The first Sparkie I employed many years ago asked me what size tiles I was using in the Kitchen, "I said I didn't know at that point, why do you ask?

"He said " where I put the power points will make it easier for the Tiler, I always try to work for the bloke that follows me".

This is something that has stuck with me and I have worked hard to achieve through all parts of the constructions ever since.

[chrisp]

Daniel,

The year 2000 version of the standard would have been in force at the time that the CoES was issued. Here are the relevant quotes:


3.9.4 Protection against mechanical damage

3.9.4.1 General
Wiring systems installed in positions where they are likely to be subject to mechanical damage shall be adequately protected in accordance with Clause 3.3.7 and the applicable requirements of Clauses 3.9.4.2 to 3.9.4.6.

3.9.4.2 Wiring systems located in or under floors
Wiring systems in or under a floor shall be sufficiently protected to prevent damage caused by the intended use of the floor.
Wiring systems shall be protected by one of the methods outlined in Clause 3.9.4.6 if they are —
(a) within a concrete or similar floor at a depth of less than 50 mm from any surface; or
(b) fixed in position below a timber or similarly fixed floor less than 50 mm from the underside of the floor.


3.9.4.3 Wiring systems located above ceilings
Wiring systems which are installed above a ceiling shall be protected by one of the methods outlined in Clause 3.9.4.6 if they —
(a) pass through or are fixed in position within 50 mm of a ceiling fixing support; and
(b) are less than 50 mm from the surface of the ceiling material in contact with the fixing support.


3.9.4.4 Wiring systems located below roofs
Wiring systems installed below a roof shall not be installed through any space formed between the roof material and its immediate support.
Wiring systems shall be protected by one of the methods outlined in Clause 3.9.4.6 if they pass through the immediate roof support, or are fixed in position, within 50 mm from the underside of the roof material.

And the section referenced...


3.9.4.6 Protection methods
Where protection of the wiring systems outlined in Clauses 3.9.4.2 to 3.9.4.5 is required they shall be —
(a) provided with adequate mechanical protection to prevent damage; or
(b) provided with an earthed metallic armouring, screen, covering or enclosure; or
(c) protected by an RCD with a maximum rated residual current of 30 mA.



The text in blue is an amendment (Amendment 1) that was issued in September 2001. I don't have record of the pre-amendment text (it was a "replace second paragraph with ..." amendment). Nor do I have any record as to when the amended version of the standard was in force.

However, the preceding text makes it quite clear that 50mm clearance was the expectation.

In any case, even if the "roof" clause was vague or not in force at the time, the "ceiling" clause would have been in force and violated.

The 'fix' would be to have the light circuit RCD protected.

[Daniel Morgan]

Thank you Chrisp, I'll hand the issue back to the Electrician that signed the Certificate of Compliance.

Could the existing RCD be used or would it require an extra RCD?

If it requires an extra one, could the existing switchboard remain?

And before they all jump on me suggesting things like dodgy DIY and call an Electrician,
I would like to know as there is limited room to fit a larger switchboard physically.

[Bros]

That switchboard has heaps of room as there are numerous blanks fitted and it will be easierto get another RCD as they are a cheap as chips and you don't need to do any ceiling modifications.

[LinesElectrical]

Number limits on putting circuits on rcd's only apply to new work.
With existing there is no obligation to upgrade to RCD's (so long as the Instalation is or was compliant when installed) it is considered additional protection and you can put as many circuits as you like within reasonable limits of current on one rcd in an upgrade situation.
So technically they could just pull a tale over to it however the reason we tech talked your install is the photos showed no circuit labeled lights. You should really identify the breaker by turning each one off and on till you find it and ensure no power points go out, ensure it is suitably sized also label it accordingly.

Or you could do nothing and forget it upto you.

[Daniel Morgan]

With existing there is no obligation to upgrade to RCD's

"New regulations require all residential homes to be fitted with two RCDs protecting all power and lighting circuits for all new tenancy agreements made after 8 August 2009.
Landlords must arrange for two RCDs to be installed at their rental premises by 8 August 2011 for continuing tenancies."

Information for agents - EnergySafety - Department of Commerce (http://www.commerce.wa.gov.au/energysafety/RCD/agents.htm)


Or you could do nothing and forget it upto you.

Really?

[Bros]

In defence of LinesElectrical how was he to know you were talking about a rental I assumed the same has he did it was an owner occupied house.

A second point is your location is listed as Australia how were we to know you were from WA. The regulation stated can vary from state to state.

As for the statement you could do nothing is correct but if an electrician added an extra smoke detector he would insist on fitting an RCD as that is the rule now. Rules are not respective as I believe there could be many houses with small mains, no earth to lighting points, no RCD fitted etc and they are still legal as that was the rule at the time.

[Daniel Morgan]

In defence of LinesElectrical how was he to know you were talking about a rental I assumed the same has he did it was an owner occupied house.

It's not just rentals, Information for electrical contractors - EnergySafety - Department of Commerce (http://www.commerce.wa.gov.au/energysafety/RCD/contractors.htm)


A second point is your location is listed as Australia how were we to know you were from WA. The regulation stated can vary from state to state.
Well he says he's from "Your capital city"


As for the statement you could do nothing is correct

"A person failing to fit RCDs in accordance with the regulations may incur the following penalty:
in the case of an individual a fine of $15,000;
in the case of a body corporate a fine of $100,000."



but if an electrician added an extra smoke detector he would insist on fitting an RCD as that is the rule now. Rules are not respective as I believe there could be many houses with small mains, no earth to lighting points, no RCD fitted etc and they are still legal as that was the rule at the time.

It becomes retrospective as you can't sell it without the RCDs, Information for homeowners - EnergySafety - Department of Commerce (http://www.commerce.wa.gov.au/energysafety/RCD/homeowners.htm)

Not may houses don't get sold or rented at some stage.

[Bros]

On many points you are wrong but as you seem to know it all why did you come and ask questions instead of preaching to us.

[BRADFORD]

If you are not selling or renting there is no requirement to fit RCDs

Information for homeownersInformation for:
What is an RCD? (http://www.renovateforum.com/What_is_an_RCD.html)

Circuit breakers, surge protectors and RCDs (http://www.renovateforum.com/Circuit%20breakers_surge_protectors_RCDs.html)
Types of RCDs (http://www.renovateforum.com/Types_of_RCDs.html)
Testing (http://www.renovateforum.com/Testing.html)
RCD Laws (http://www.renovateforum.com/RCD_laws.html)

homeowners
real estate agents, landlords and tenant (http://www.renovateforum.com/agents.htm)
electrical contractors (http://www.renovateforum.com/contractors.htm)
Frequently asked questions (http://www.renovateforum.com/faq.htm)
RCD - new laws (Factsheet PDF) (http://www.renovateforum.com/PDF/Misc/DP0898_RCD_Flyer_002.pdf)
Media advertisements (http://www.renovateforum.com/advertisements.htm)

Two RCDs protecting all power and lighting circuits must be fitted to a residential property before it can be sold and the transfer of title takes place. Penalties apply if RCDs are not fitted and the land title is transferred to another person.
If you own a residential property and don’t intend to sell, lease or rent it then you do not need to have RCDs fitted to protect all the power and lighting circuits.