Zero Ohms… Not Really!
The goal in ground resistance is to achieve the lowest ground resistance value possible, that makes sense economically and physically, when contacting the earth, also known as the soil/ground rod interface.
Ideally, a ground should be zero ohms of resistance, but…
Unfortunately, there is not one standard ground resistance threshold recognized by all certifying agencies.
The NFPA and IEEE recommend a ground resistance value of 5 ohms or less while the NEC has stated to “Make sure that system impedance to ground is less than 5 ohms specified in NEC 50.56. In facilities with sensitive equipment it should be 5ohms or less.”
The telecommunications industry has often used 5 ohms or less as their value for grounding and bonding while electric utilities construct their ground systems so that the resistance at a large station will be no more than a few tenths of one ohm.
Reference: Fluke Earth Ground Testing Fact – Distributor Training Program
that very good
But I have reach to less than 1 ohm of earth resistance by my special way
can any one tell us the IEC standard for earthing resistance value in general in Oil fields please.
Seeking your support, appreciate if you could share to me MV Protection coordination study sample.
Sir what is the correct value for earth trasformer
There is no NEC 50.56.
NEC 250.56 11th edition stated 25 ohms and less.
NEC 250.56 is excluded from 12th edition
In my company, a telecommunication giant in Nigeria, the standard earth resistance value ranges from 2.0 Ohms and below.
Dear Emeka Chime,
Please let me know, the standard earth resistance value ranges from 2.0 Ohms, the 2.0 ohms is quote from what authority or international standard?
Thanks so much
Very Educative … Thanks Edvac …!
is there any reference about the resistance value between clean and dirty earths.
Nice one, very educative, can i get a earth resistance tester and at how much
I have checked the earth resistance and it’s result is point zero one six seven so kindly tell me about the earth, that is good or not
Hi, meter reads o.23 Ohms, is this good or bad?
yes very good
I installed a 5kva inverter in a house that has a thunder arrester and it’s earted. But the inverter was still destroyed by thunder. This made me to to run a test on the earthing and was discovered it was 27ohms. How come it was only the inverter that was affected and not the house appliances as well
Because inverter has an isolation transformer and surge circuit inside to avoid cascading the fault current goes.to other appliances
Earthing for Any equipments is Design always request customer for Soil ERT Reports and Design for Equipments or any Kind of Grid.
Earth Enhance Compound Role is bigger than Metal Part becuse we use Metal to consider Falut Current and Life for Metal but without Good and Quality Compound its not possible.
Avoid to use any mineral who can Damager or Corrosion your Metal Later .
India Follow IEC as well IEEE .using CDEGS Software for Desiging Earthing and Lightning
We has to mentioned Latest Tech Documents is our inquiry or Tender
Like to buy Tong earth tester like in the photo please get back to me.
Would like to buy an earth tester (ideal ground resistance meter)
Sir sgp course available ?