Earth Rod Spacing

[Doomed]

Had to fit 2 earth rods to TT 2 adjacent buildings.
The only available soft ground was a approx 3 foot gap between the two buildings.
I have spaced the rods a good distance from each other, but could someone point me in the direction of the regs to do with spacing between the rods for use in my report.
Ta.

 

[Marvo]

Do the UK regs actually specify a spacing distance? We try to keep rods 10 meters apart as a rule, sometimes less than half that distance is sufficient, sometimes not it depends greatly on the make-up of the ground, the height of the watertable and many other factors that don't remain constant from location to location

 

[Engineer54]

Spacing of earth electrodes are generally based on the length/depth of the rods used... if 3 metre rods used, then a space of not less than the 3m length must be provided. This is so that there is little chance of any overlapping of the rods areas of influence. It is also recognised that there is little benifit if any, in exceeding 1.5X the rod length spacings...

 

[GLENNSPARK]

I think it went up from 3 meters (16th)...to 6 meters (17th) but this may just be placement of spikes for testing..........

 

[Marvo]

I have several different makes of earth spike resistance testers and they come with different lead lengths and use different test spike distances.

 

[mark1979]

as eng54 says driven depth=separation

 

[GLENNSPARK]

FIG 2.6..GN3..(P47)
shows temporary spikes placed 6 meters either side of T2 which itself is 15-25 meters from the electrode under test.
542.2.2 GN3 also quotes in paragraph 4 that the test spike (T1) is at least 10 times the maximum dimention of the electrode system, e.g. 30m for a 3 m long rod electrode.

 

[Engineer54]

I think it went up from 3 meters (16th)...to 6 meters (17th) but this may just be placement of spikes for testing..........

That doesn't sound like even test spike distances...lol!!! Most of the test manufacturers kit that i have used, generally ask for between 20 to 50m to the current test spike, and 10 to 25m for the furthest potential test spike!!

EDIT ...Anyway were talking about distances between driven earth electrodes, ...not earthing test kit spacings of test spikes...

 

[Chr!s]

The rod will form a resistance shell 1.1 x it's length in all directions. So two rods same length, 2.2 times the length separation.

 

[Engineer54]

The rod will form a resistance shell 1.1 x it's length in all directions. So two rods same length, 2.2 times the length separation.

The sphere of influence is is rarely if ever symmetrical far from it in fact.

 

[Chr!s]

The sphere of influence is is rarely if ever symmetrical far from it in fact.

True, though if you stick to a hemisphere of 2.2 x Length you wont go far wrong.