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Earth electrode test


sdc8843

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Sorry guys another question.

Earth electrode test using a Earth Fault Lopp Tester.

One book i have says connect lead to incoming phase conductor at the supply side of the main switch and test

IEE exam success says connect to outgoing phase of main isolator. Which i assume is not the supply side.

1. Does it matter which side its connected to, my understanding is supply side

2. When some books state about connecting a Neutral during this test does it mean if you are using a 3 lead or 2 lead. 3 lead connect neutral, 2 lead don't.

Thanks

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I would think probably best to test incoming supply side but only main earth and not bonding and to do that supply should be off. All depends what tester you have, mine are all three wire so all connections need to be made.

Batty

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in the IEE it also says make sure all breakers are open (because the earth is dist) so pretty much the same as having probs on the supply side

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As said, you need to ensure NO parallel earth paths are present so the main earth connection to earth electrode needs to be disconnected.

If the main earth is disconneted... the installation is unsafe for any non-skilled persons to use.

Therefore the installation should be isolated... or SWITCHED OFF!..

best place is the main isolator switch.....

so to do your test readings you would need to be on the incoming side of the switch... because the outgoing side would be dead.

obviously you could switch off all of the individual MCB's / RCBO's, and use the other side of the main switch....

but it is just quicker and easier turning the main switch off.

:)

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Sorry guys another question.

Earth electrode test using a Earth Fault Lopp Tester.

One book i have says connect lead to incoming phase conductor at the supply side of the main switch and test

IEE exam success says connect to outgoing phase of main isolator. Which i assume is not the supply side.

1. Does it matter which side its connected to, my understanding is supply side

2. When some books state about connecting a Neutral during this test does it mean if you are using a 3 lead or 2 lead. 3 lead connect neutral, 2 lead don't.

Thanks

main isolator should be off as SL has stated, so you need to test on the incoming side. really, it doesnt matter where, as long as its as close to head as possible. the neutral lead is used where RCD's are in use, otherwise a simple phase and earth lead is needed. although setting some testers (i.e fluke) may need neutral or it wont test

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I agree with the above posts, fluke as the one I have require a nuetral so would need three leads to test.

Just one note there is now no real need to do a Ra unless you are getting really high readings, a simple Ze at incommer would be ok.

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I would also opt for testing at the incoming side of the Main isolator, the main reason being ,as already stated ,the Main earth connection for the installation will have been

temporarily disconnected..Maybe some books advocate testing at the outgoing terminals[providing all breakers are off}to ensure there is no possibilty of any resistance across the main switch contacts affecting the reading, although this would be unlikely in the vast majority of cases, and it would only make any real difference on tns or tncs systems as tt sysstems are usually in the tens of ohms anyway......additionally ,lots of systems still use an rcd as the main isolator, therefore a non trip "D-loc " etc. type of setting has to be selected on the meter if going across the outgoing side.....the readings on non-trip loop tests ,I find, are never as accurate as normal loop ranges, so thats another point in favour of going across the incoming side where the non-trip setting does not need to be used.{ or 2 lead type tester selected }

a1spark

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