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Old 16-04-2017, 07:56 PM   #28 (permalink)
mudcrab
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Last Online: 16-04-2017 11:15 PM
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mudcrab Might not make it as a Thai Expat
Quote:
Originally Posted by Slick View Post
Quote:
Originally Posted by outdoorbloke
Ended up going with a 2.2 meter one from the local shop as I didn't have a big enough car to get the 3 meter one home from watsadu.
lol it should be fine, but after installation, you can do like SandMike says and check the resistance with an Ohm meter/DVOM if you are really concerned about it.

I had just one regular sized one for the whole house driven by the septic tank and it was just fine. Wired into the consumer unit's earth bar, I used that one earth stake to earth everything and used a single main RCBO.

Promise you thats gonna be better & safer than 99% of most home installations here.

I debated driving one for each hot shower and giving them all their own, but decided its overkill & kinda pointless.
Oh dear.....not quite accurate information here.
Good luck checking the resistance to earth of an earth stake using a multimeter.

The earth resistance test is a particular test requiring some very special instrumentation....how far from the earth stake are you pushing the multimeter lead into the ground? 2cm, 20cm. 2m??

Its a very a regulated and proscribed test carried out at specified intervals, usually for Standards compliance purposes and often on HV/LV substations, very rarely employed on a domestic install.

I think what you are referring to is the resistance from the earth bar in the CU to the earth stake. That can be checked with a multimeter, although in Oz these days the regulators require an impedance test not a resistance test. 2 ohms is still specified as ok.

Of course you still need to check the earth stake periodically as copper (wire) can and will corrode.

Consider installing RCD type devices that will trip out on current imbalance...even if your earth connection has failed. I wont discuss equipotential bonding at this point.

FYI RCD = Residual Current Device. They work on the principle of current flow out of the device and back in should be close to equal. If it is not then some portion of the current is going somewhere it shouldn't....possibly you.
20mA is a common standard these days.
You can get them combined with circuit breaker protection so they provide both people and cable protection. Don't forget to test them....push the test button every 6 months or so to make sure they work.

Pretty well mandated in Oz for both power and lighting circuits.

I believe I read something recently indicating something similar is now required by PEA for new installations.
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