Why the need for an earth spike test kit?

[HappyHippyDad]

I am about to put in a copper rod to TT a garage.

I have a megger 1731 but do not have the Earth spike test kit.

I will be able to test the Ze once the rod is in place and wondered what the difference is between testing the Ze and testing the Ra with a spike test kit?

Is it sufficient to just test the Ze rather than purchase a test kit to test the Ra. Will the result be the same? I.e. Ze = Ra

I'm not entirely sure if my terminology is correct, I know Ze is for the external EFLI and am assuming Ra is when you use a test kit rather than the live test?

 

[westward10]

Ra is the sum of resistances of the electrode and earthing conductor and does not include the line resistance as Ze would. Ze is measuring the earth fault loop path, Ra is only measuring the electrode and earthing conductor.

 

[Deleted account]

Personally for a garage I dont think you need to. I always just stick the rod in and Ze it.

If your not happy with the read stick another one in.

 

[Strima]

Carrying out an EFLI test (test method E3 in GN3 page 64) on a rod is an acceptable method.

I only used spike kits on new installations where there was no supply available and for initial verification.

 

[davesparks]

Carrying out an EFLI test is acceptable if RCDs are being used for fault protection for all circuits.

 

[Dustydazzler]

I haven't seen anyone use a proper earth electrode tester on site since the 1990s

To be honest I don't think any new sparks would even know what to do with one

 

[richy3333]

We Ra test all the time.

@happyhippydad I might have a spare Megger Ra test set if you want it. 3 sets of leads and the probes. Just PM me and I'll search it out of the storage box

 

[Dustydazzler]

Now that's an offer you can't refuse

 

[HappyHippyDad]

We Ra test all the time.

@happyhippydad I might have a spare Megger Ra test set if you want it. 3 sets of leads and the probes. Just PM me and I'll search it out of the storage box

Richy, that's really kind of you
I'd love to have it to have it but only if you are absolutely sure you're not going to need it (have a proper think). Also, I'd want to give you something for it..... money, beer, whiskey or something to charity (plus postage)?

 

[HappyHippyDad]

Very nice people on this forum (looking for a 'humble' smiley, but can't find one).

 

[JK-Electrical]

I haven't seen anyone use a proper earth electrode tester on site since the 1990s

To be honest I don't think any new sparks would even know what to do with one

This video should help any such new spark ....

​

 

[HappyHippyDad]

My Megger earth spike test kit has just arrived from @richy3333 .
He refused all payment, even postage.
What a top chap .

 

[westward10]

Top man Richy.

 

[richy3333]

Please you'll make me blush. Its always good to help each other out in the trade

 

[HappyHippyDad]

We have thunder and lightning here.... however, I have a new toy and have just been in my garden to experiment! Popped my spare 5/8" rod into the ground about 9", positioned the potential and current electrode correctly (in the pouring rain with a smile on my face) and pressed play! 180ohms.

I then hammered in it to about 15" and it went down to 96ohms.

This is all very exciting!

I darn't hammer it in any further as I did that in my garden as a practise when I first started out some years back (thinking I could just pull it out afterwards) and I had to dig a big hole to get it back out.