Earth Wires - uninsulated

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Old 05-23-18, 07:48 PM
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Earth Wires - uninsulated

Hey Guys,

A friend of mine has a property that needs some structural repairs done and I am helping at the moment.

I noticed the earth wires behind the fuse board have very little to no insulation around them and also an earth wire or two running behind the wall completely naked.

Is this acceptable? A licensed electrician said to me it is ok if it's old work.
I thought an uninsulated earth wire(even though it is just the earth) running right next to a live wire is kinda
worrying 'cos if the live wire insulation gives way on some spots it can easily short circuit to the earth.
I am sure circuit breaker/fuses/RCDs will trip and save a major issue if they are property installed.

But is it ok to have such open earth wires? I've never seen like that before, hence the worry.

Please post your opinion and advice.

Is it safer to have insulated earth wires as I've seen in all the places before?

I am in Australia.

Thanx
 
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Old 05-23-18, 07:58 PM
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Bare grounding conductors run safely in NM cables in the US without issue. If an energized conductor touched the bare it should trip the breaker .
 
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Old 05-23-18, 08:42 PM
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Your worries are paranoia.

If a live wire's insulation gives way, it would be just as likely to short to metal parts of the fuse board or to a metal junction box (which are normally earthed) as it might short to a juxtaposed bare earth wire. Therefore we all know (or should know) that a wire whose insulation is so biodegraded so as to be likely to give way must not be used as a live wire. And normally a wire in good condition run alongside bare earth wires is considered an acceptable risk. Now there are a few cities where code does not allow bare earth wires but that is those cities' code and not necessarily additional meaningful protection against short circuits.
 
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Old 05-23-18, 08:49 PM
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Looking at your wiring..... ground is the least of your worries. I'm guessing no metal panels or electrical boxes are used down there. That's more frightening.
 
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Old 05-24-18, 01:25 AM
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Yes, the fuse board is not that good looking(not pictured above). What you see is the wiring behind the fuse board that. The fuse board has been upgraded with RCDs for each circuit. But, that is for another thread and the issues related to that.
I was bit surprised to see the naked earth wires behind the wall because I've never seen that before, but apparently they did that back in 70's or so around here. Nowadays the earth wire is multistranded insulated wire as the live and neutral wires.

How about during lightening? Does these unisulated earth wires behind the wall carry any risk during such events?

Thanx
 
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Old 05-24-18, 01:50 AM
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If lightning strikes... a little bit of insulation is not going to stop it.
 
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Old 05-24-18, 07:07 AM
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Yes, of course. That kinda high voltage isn't stopped by tiny bit of plastic covering around the wires.
So, if the earth wires don't need any insulation at all, why do we bother in the first place?
Cosmetic finish or aesthetics?
 
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Old 05-24-18, 02:10 PM
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Many, if not most, non metallic cables like romex use a bare ground. I see some of your cables have a bare ground and some have an insulated one. I don't know if that is something in your code or just cable specific.
 
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Old 05-24-18, 08:13 PM
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These days bare naked earth wires aren't allowed in Australia. What you see in the pictures was from old work, perhaps from 70's. Wires in this property(most of the live and neutral) are single core thick wires whereas earth wires are multistrand but with no insulation on it's own around it. Yes, some wires has insulated single earth wires which I think are later additions.

I am not sure what you meant by "non metallic".

Thanx
 
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Old 05-24-18, 09:37 PM
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Non-metallic just means that the individual conductors (insulated or bare grounds) are in a flexible sheath, most often of some plastic or rubberized material. This doesn't include power cords of course....though I guess you could stretch the definition to cover some types of that as well.

The most common here in the states is NM-b. It is used in various gauges for all the branch circuits in most residential and commercial settings. Some municipalities (New York City being one I believe) require all metallic sheathed or metal conduit be used.
 
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Old 05-24-18, 10:58 PM
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Googling NM-b, it appears that's what's been used in Australia for quite a while as well.
Individual conductors(live, neutral, earth) wires are in an insulated sheath and then the whole three wires are in a typically white colored sheath.
 
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