2395 Last Night ?

[ackbarthestar]

I have the OSG 16th ed and the two 17th ed GN3 (I cannot find my 16th Ed GN3)

The 16th ed test (in the OSG) and the 17th Ed:2008 (GN3) both say you may use the EFLI method if the rod is used in conjunction with an RCD


The 17th ed amd 1 GN3, has now removed this RCD requirement. This is what is new :cheesy:

Ah, now I see where you're coming from.

I can see why they changed it. Testing through a RCD will always give spurious results. Maybe this test was invented so that the novice always had the protection of the RCD if testing live, but then decided that anybody testing live should know what they're doing.

There is nothing new here, as I said before. Testing across a RCD is more likely to give overestimated results rather than referring to 411.5.2 and .3

 

[spark 68]

No, No, Ackbar it has never suggested that you test through the RCD, you would Isolate the supply and test as you would have normally tested for Ze, disconnecting the earthing conductor and testing directly on that.

What it was saying previously was, that so long as the installation was using an RCD that you could use the EFLI method, but now it just says using the EFLI method may give less accurate results.

I think it was as brman said here:

On my 2395 I am sure i was taught that the EFLI was only valid if a RCD was present as accurancy was not so important in that situation but it does appear from the regs that this bit has been dropped now. To be fair the updated GN3 wasn't available when I did mine!​

Anyway it seems as if the new GN3 has relaxed the regs a bit, and what I was asking was " can we use the EFLI method for generator rods and the like ?" , as previously we couldn't according to the regs, maybe some did anyway and that was why the regs have been relaxed, who knows ?

 

[ackbarthestar]

I've always read this test as:
1/ Where there is a supply connected then you have a choice of electrode testing using the spike method or EFLI test or Clamp test
2/ Where there is no supply then apply the proprietary earth electrode test.

I think we are speaking the same language

 

[spark 68]

I've always read this test as:
1/ Where there is a supply connected then you have a choice of electrode testing using the spike method or EFLI if to be used in conjunction with an RCD (now relaxed, Amd1) test, or Clamp test
2/ Where there is no supply then apply the proprietary earth electrode test Good point.

I think we are speaking the same language

Yes we are saying broadly the same things, I have added the bits in red.

The part with no supply obviously makes sense, how else could you test it ? lol

I wonder now about how to test the generator rods using the EFLI method, if it is at all possible ?, maybe if there is a supply on site it would, but would the results be accurate enough ?

It is good to talk about these things, I must thank Malcom too, for drawing my attention to the updated regs, as if he had not pointed them out I would not have noticed the subtle changes here.

 

[ackbarthestar]

I wonder now about how to test the generator rods using the EFLI method, if it is at all possible ?, maybe if there is a supply on site it would, but would the results be accurate enough ?

Read more: http://www.electriciansforums.net/i...ns/59460-2395-last-night-4.html#ixzz1z4l0bDfA
​

I agree, some good points made.
How i see it, Using class I equipment, or more appropriately where an earth return path is required for fault currents, you are likely to need 2 electrodes, one at the source and one at the point of utilization.

An established TT installation has an electrode already So by using a separate source, such as a generator with a change over switch, will utilize this electrode. I think the problem comes when the generator has built in RCD protection in the loop.

To get a realistic result then I think you will need to use a proprietary electrode tester.