Electrical - Metal Trusses in roof

[httttt]

Hey people,

I need some advice from any electrician out there in TOCAU world.

See the picture attached.

I am looking to purchase this home, but the building and pest inspectors wont go into the roof because of the wiring and metal trusses which is annoying because we don't get the full report we paid for.

Anyway, does any Electrician know if that sort of wiring is completely unacceptable? Or what the laws are concerning wiring in houses with metal trusses?

I'm going there tomorrow morning to check it out for my self (don't worry, I wont touch anything).

Thanks

[Guni]

Those blardy union blargers!!!!

<_<

Get a partial refund or something .....

[VF-X]

Soz Jeff.. Can't c sh*t with the attachment..

[Guest]

the fact that its not held down properly or in conduit kind of worries me.

I cant see any safety issues, but its not exactly the best way of doing it.

[DJKOR]

Firstly for legal issues, what I will say here is just my own opinions. They must not be taken as advise or recommendations.

What you have there is a sheathed 3-core mains cable. This stuff can basically be run though most areas of the house with no need for conduit. From looking at the AS/NZS 3000:2000 Wiring Rules, from the attached photo I would gather that what can be seen would be classified as acceptable.

For the case we have here, in accordance with the standards I don't see issues with having such a cable attached to metal components. The AS/NZS 3000:2000 Wiring Rules don't quite say anything about the material of what the cable is attached to. I've seen this type of cable run along in metal cable trays all the time. Surely if you can't attach it to metal, then these installations would not comply with the standards as well.

The only thing that I would think can apply from looking at the standards, would be the following. But this is more related to mechanical stress:

3.3.9 Other mechanical stresses

A wiring system shall be selected and installed so as to minimize damage to the sheath and insulation of cables and insulated conductors and their

connections during installation, use and maintenance.

The radius of every bend in a wiring system shall be such that conductors and cables shall not suffer damage.

Where a conductor or a cable is not resting on a continuous surface it shall be supported by suitable means at appropriate intervals in such a manner that the conductor or cable does not suffer damage by its own weight.

Every cable or conductor used as fixed wiring shall be supported in such a way that it is not exposed to undue mechanical strain and so that there is no appreciable mechanical strain on the connections of the conductors, account being taken of mechanical strain imposed by the supported weight

of the cable or conductor itself.

A flexible wiring system shall be installed so that excessive tensile and torsional stresses to the conductors and connections are avoided.

-----

3.9.3 Support and fixing

Where a wiring system is not resting on a continuous surface it shall be supported by suitable means in accordance with Clause 3.3.9.

Where necessary a wiring system shall be fixed in position by suitable clips, saddles or clamps or by means which will not damage the wiring system

and which will not be affected by the wiring system material or any external influences.

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.

3.9.4.3 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.

3.9.4.6 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.

-----

3.9.5 Wiring systems likely to be disturbed

3.9.5.1 General

Wiring systems installed in locations where they are likely to be disturbed shall be installed in accordance with the requirements of Clauses 3.9.2 and 3.9.3.

3.9.5.2 Locations

Wiring systems installed in the following locations are deemed likely to be disturbed:

(a) On the surface of a wall or on the underside of a ceiling.

(b) In a space between a floor and the ground to which a person may gain entry.

(c) In a ceiling space having an access space exceeding 0.6 m high.

(d) Within 2.0 m of any access to any space to which a person may gain entry.

3.9.5.3 Fixing arrangements

Cables likely to be disturbed shall be fixed to prevent undue sagging.

[httttt]

Cheers everyone!

Especially Daz.

I had an electrician mate check it out. Turns out that the wiring is only like that above one of the man holes (WTF?) as a ceiling fan was out into the laundry.

Thanks again.

p.s. I have never encountered a house with metal trusses like this! You have to be a snake to get anywhere up there. I'm not looking forward to installing an alarm.