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Posted By Topic: Main Earth Electrode next to Gas Bottles

NapierElec
Nov 12 2019 17:02

On a new build, the gas guy installed his gas line and bottles next to my (already installed) main earth electrode. He is now telling me at fitoff time that I need to move my main earth as it is a 'source of ignition'. I have studied the latest regs and can find nothing stating the main earth is a source of ignition. AS/NZS3000 refers to AS/NZS60079.14 Explosive Atmospheres as a reference for installing electrical equipment in explosive areas. 60079.14 refers a lot to bonding equipment but says nothing about main earths. Am I right in thinking an earth conductor is not a current carrying conductor therefore not a source of ignition?? I'm annoyed at the gas guy as the house is nearly finished and as I can't join/extend a main earth, I'll have to draw up another earth, which I don't even know is possible at this stage.
   

AlecK
Nov 12 2019 17:09

Actually the question of whether an earth electrode could be a source of ignition is secondary; because that clause of "3000" is modified by the citation in Schedule 2 of ESRs.
As a result no electrical equipment is allowed in the Zone unless is is directly related to the gas supply. 2018 edition has a matching clause.

However in this case, since the MEC & electrode were there first, it's not your work that's non-compliant, but whoever set up the gas supply too close to your electrical fittings.
   

OctaneOutlaw
Nov 12 2019 17:31

"and as I can't join/extend a main earth"

Why can't you join or extend a main earth?

Not that it should be your job too if you were there first as said above but just wondering

I've never seen anything that says yous can't join or extend a MEC
   

DougP
Nov 12 2019 18:12

I would guess that the pipe is probably not a problem, as you only need 25mm separation from the earth conductor.

There's nothing wrong with joining the main earth conductor. I usually use a crimp link and heatshrink. So if necessary, you could join the conductor and run in conduit to the new earth stake. It would only need to be moved 1500mm at the most presumably.

I don't think that the main earth conductor in conduit would be considered "equipment", so there shouldn't be any problem with that being within the zone.

I would also be getting the cost of the variation approved before doing the work. Unless of course the gas cylinder location was marked on the plans, and you put the earth too close?
   

NapierElec
Nov 13 2019 05:36

Thanks guys. Looks like I'll have to move it. I was taught in my apprenticeship a main earth has to be continuous and I've been doing it like that for years. I've just now combed the regs and yea, there's nothing in there that says it has to be continuous. Ha.
   

AlecK
Nov 13 2019 07:12

Even when the old Reg said "continuous", that didn't prohibit permanent joins such as used by DougP (and me).
"continuous" prohibited breaks, and was aimed at connections that could be disconnected thus rendering the MEC (then "earth lead") useless.
   

CraigW
Nov 21 2019 13:57

Sometimes they are better moved and rejointed than stuck under a deck