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#145393 05/06/06 08:53 AM
Joined: Dec 2004
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kiwi Offline OP
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Today I found a house with lots of lighting circuits wired in red twin fire cable. This was original wiring installed as built.

Is this allowed ? I thought red sheathed twin cable was only for fire alarm wiring.

Is (was) it allowed in a domestic building ?

Is there a requirement that makes it mandatory that the house be re-wired ?

#145394 05/06/06 07:23 PM
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I think that it is illigal to wire a house in red alarm type wiring.

Also I'm not sure if it is rated for 230 Volts AC.

As far as I'm aware it's only 0.75 or 1 mm² and NO EARTH !

Sent your question to th EWRB, see if John Sickels has the answer.

Cheers

Ray


The product of rotation, excitation and flux produces electricty.
#145395 05/06/06 08:31 PM
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Kiwi,
As far as I'm aware, the red-sheathed 2-Core TPS cable has the same properties as it's white-sheathed brother, ie: has a 600V/1kV rating, the only difference being that it has a Red outer sheath to denote the system as a Fire Alarm system.
Even so, it has a conductor size of either 1.0mm2 solid or 1.5mm2 stranded.
As Ray rightfully mentions, it is contrary to the Regulations to install a cable in Domestic Installations without an integral Earth conductor.
Having said that, I've worked in heaps of houses where the switch wire from the batten-holder to the light switch (in a 3-plated system) is only a 2-Core (Red/Black) cable.
Also depends on when the place was wired originally.

#145396 05/09/06 04:56 AM
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kiwi Offline OP
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Surely it must have been allowed to wire lighting circuits in the past with no integral earth. I've seen it a million times. Or was it a popular cost-cutting measure that went unnoticed by the inspector ?

Some people may have thought that wiring a domestic dwelling in red twin was okay as there was no fire alarm wiring anyway.

#145397 05/09/06 06:09 AM
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In the U.K., the IEE Regs. only required earths from 1966 onward. Prior to that, earths could be omitted on lighting circuits so long as certain conditions were met: No switches with exposed metalwork, any metal light fixtures to be mounted out of reach, etc.

We had a brief discussion about this here (toward the bottom of page 1 and the top of page 2):
https://www.electrical-contractor.net/ubb/Forum9/HTML/000772.html

#145398 05/09/06 06:11 AM
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Quote
contrary to the Regulations to install a cable in Domestic Installations without an integral Earth conductor

If you're referring to AS/NZS 3000, there's nothing against wiring the circuits in twin with a separately run earth wire to each point.

I can't think of any rule that disallows using a cable with a red sheath in a domestic installation that doesn't have a fire alarm panel.

#145399 05/10/06 04:33 AM
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kiwi Offline OP
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That may be right Pauluk, as most of the twin lighting wire I'm finding now is from houses built in the 60's.

Has anyones regs ever stated that a metal light fitting doesn't have to be earthed if it is placed higher than a certain measurement above ground level ? I've heard that theory alot here and I've never been able to find anything in AS/NZS 3000. ( I can't be bothered looking in the old regs ).

#145400 05/10/06 05:55 AM
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Quote
Has anyones regs ever stated that a metal light fitting doesn't have to be earthed if it is placed higher than a certain measurement above ground level ?

when it's not in an earthed situation which means more than 2.5 metres above the ground or any exposed conductive part.
Check the definition for earthed situation and Clause 5.4

#145401 05/11/06 03:38 AM
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Quote
If you're referring to AS/NZS 3000, there's nothing against wiring the circuits in twin with a separately run earth wire to each point.
No I'm not actually, before the AS/NZS thing and still, we have our own Regulations here, have you read them?.
The fact that local Regulations are being watered down in favour of a "one size fits all"
across countries, is just one of the reasons I'm happy with leaving this industry.
AS/NZS 3000 is nothing more than a compromise, from both sides. [Linked Image]

#145402 05/11/06 04:47 AM
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Each state has it's own electrical regulations. AS/NZS 3000 is simply a document and requires local legislation to make it enforceable.
Why do you consider the wiring rules a compromise? What don't you like about it?

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