Earth Electrode Testing

[laxmi]

Hi,

How to test an earth electrode resistance for Lightning Protection System in the middle of large concrete pad? I cannot not find a soft ground for spikes to drive in for testing. Is there any other ways of measuring the earth electrode resistance value?

Thanks

Laxi

 

[uksparks]

Just do a Ze at the origin, I guess thats as good as anything.

 

[Former Sponsor TM]

Have a look at hiring (or purchase at £500+) an earth resistance clamp which induces a current into the system without you needing to disconnect the main earth.

Or, as above an impedance test

 

[davesparks]

Just do a Ze at the origin, I guess thats as good as anything.

No it's not, that would give you Ze not the resistance to earth of an electrode.

He hasn't even said whether the rod is for earthing an installation, lightning protection or any other purpose!

 

[trev]

He asked about lightning protection a day or two ago so I'm guessing it's for that.
Could be wrong of course.

 

[Engineer54]

Have a look at hiring (or purchase at £500+) an earth resistance clamp which induces a current into the system without you needing to disconnect the main earth.

Or, as above an impedance test

The trouble with those earth clamps, is that you need room to get the jaws around the earth rod, and there is generally very little room to do this when earth rods are within a flush to ground earth pit...

EDIT... How many electrodes (earth rods) are there along each side of the building being tested and how far apart are they?

 

[jay sean]

When carrying out testing with a clamp meter you would disconnect the tape from the rod and bridge the two with a short 25 mm cable with clips

 

[laxmi]

The trouble with those earth clamps, is that you need room to get the jaws around the earth rod, and there is generally very little room to do this when earth rods are within a flush to ground earth pit...

EDIT... How many electrodes (earth rods) are there along each side of the building being tested and how far apart are they?

Hi,
Thanks for your help on this matter. I am actually testing earth rod resistance for Lightning Protection System. There are four down conductors on each corner of the building. I managed to measure all three earth rod resistance value. But there is no soft ground around the electrode rod that belongs to fourth down conductor. One 2 m long copper solid rod is being used on this down conductor . The nearest soft ground is approximately 40m away from the test point. The surrounding area is concrete pad.

Is there any means of testing the earth electrode resistance for Lightning Protection System?

Thanks

Laxi

 

[Engineer54]

Unless this building is very small say 10m to 15m square, then it doesn't sound like you have enough down conductors depending on what the building is and building construction material.

You could use weighted metal plates in contact with ''wet'' concrete in place of your test spikes and compare values with that of the other 3 earth rods. BTW i've more often than not used test leads in excess of a 100m for the C1 test spike. So 40m isn't, as far as i'm concerned any great distance when testing earth rods...

 

[richy3333]

Hi,
Thanks for your help on this matter. I am actually testing earth rod resistance for Lightning Protection System. There are four down conductors on each corner of the building. I managed to measure all three earth rod resistance value. But there is no soft ground around the electrode rod that belongs to fourth down conductor. One 2 m long copper solid rod is being used on this down conductor . The nearest soft ground is approximately 40m away from the test point. The surrounding area is concrete pad.

Is there any means of testing the earth electrode resistance for Lightning Protection System?

Thanks

Laxi

if you are using Megger equipment to do your testing there is no need to sink the spikes if you can't. Speak to Megger technical and they will walk you through the test procedure.

 

[laxmi]

if you are using Megger equipment to do your testing there is no need to sink the spikes if you can't. Speak to Megger technical and they will walk you through the test procedure.

Hi,

Thanks for your help, really appreciated.

Lax