Earth rods in triangle configuration BS 7430:2011

[Keops]

Hello, 

Id really appreciate if you could help me to solve some doubts from the BS 7430:2011 ( the part that talks about the electrodes resistance calculation) 
It is not quite clear for me if, in order to calculate the resistance to earth of a 3 rods triangle system, we ONLY use the equation given on 9.5.8.1 "three rods at the vertices of an equilateral triangle", or  we ALSO have to calculate the resistance of the round conductor and then the total final resistance of the paralleled system. 


In the section "9.5.8. Miscellaneous electrodes", there are several configurations like Three rods at the vertices of an equilateral triangle, two strips set at right angles to each other meeting at one corner... 

- The equation given on 9.5.8.1, apart from the errors presented on the edition 2011 which seem to be amended on the a1:2015, doesn't include the diameter of the conductor that connect them all together. 

-How is it possible that if a parallel connection is needed between the three rods and the ground electrode, it is not mentioned on the code? 

- Assuming we have to calculate resistance of the round conductor too, Do we use the straight run round conductor electrode? 

Thanks a lot in advance

 

[Manator]

"The equation is for interconnecting rods so just use the equation as written" quoted from IET forum reply given by OMS

 

[steptoe]

Why do you actually need to calculate this,?

as opposed to measuring it,? 

 

[Sidewinder]

"The equation is for interconnecting rods so just use the equation as written" quoted from IET forum reply given by OMS

I was just about to say exactly the same Manator!

Keops, OMS, REALLY DOES KNOW HIS STUFF, trust me, I know him.

Also Mapj1 has, IIRC, agreed with OMS, Mapj1, is also a very intelligent & competent Engineer.

 

[Manator]

I can not ever say that I have seen OMS get it wrong, so if he says it, it must be right. His insight has also changed the way I do some of my work.

 

[Sidewinder]

Manator,

Once you find out what OMS does, for whom, and who he is, then you will understand more.

I can't reveal who he is, hence why he used an anonymous pseudonym.

I will say that he isn't employed by any of the scams, or the IET.

I other words he does this stuff for a living for a commercial employer.

 

[Davethsparky]

Unfortunately the British standard in question is prohibitively expensive for the majority of us to be able to justify buying it. So as a result a lot of us end up using third hand information gained from freely available information online rather than referring to the actual standard (those of us who don't believe in the 200ohm pidgeon-poop that gets far too much publicity)

 

[Tony S]

The OP has the answer from elsewhere.