Current Standards for Earth Resistance in Detached Houses: Is 20 Ohms Acceptable?

Question

Hello,
resistance measurements showed 20?.
I have two fields in the protocol:
Measured resistance and allowable resistance.

I searched, found some older posts from 2003 and it said 10-50?.

How is it now?

greetings
Patryk Słupikowski

jarecki 86 · Accepted Answer

There is no such thing as Permissible / Required earth resistance in a detached house . However, there is a required grounding resistance for surge arresters, which is usually 10 ?. In the case of the connector on / near the building, it may also be a requirement imposed by the power industry, i.e. the working ground of the PEN conductor - 30?.

andpol · Answer

The required earthing resistance depends on the type of network, size and type of protection, and on the purpose for which the earthing system is to be used.

jarecki 86 · Answer

I do not think the question was about earthing for the purposes of electric shock protection. If it were to be otherwise, I am asking the author of the thread to correct it.

Enpro · Answer

In the protocol you have, as you wrote yourself, the measured value, this is what you measured; the permissible value is a value depending on what it should be, i.e. if protective is up to 30 ohms or lightning up to 10 ohms and the value after conversion by the soil factor (dry, wet, humid) which you compare with the permissible value and on this basis you determine whether the earth electrode after conversion meets the norm or not.

kasprzyk · Answer

Hello I use the table from SonelPE4: As colleagues wrote, if the earth electrode is to be used in a lightning protection system, the recommendations of the surge arrester manufacturer are often

kkas12 · Answer

This is rubbish sucked out of the finger.

jarecki 86 · Answer

If you take into account the provisions of point 5.3 of the N-SEP-E-001 standard, it's hard for my colleague enpro refuse to be right -
PEN (PE) conductors of power lines should be connected with PE protective conductors of electrical installations of energy consumers, earthed through the main earthing bar of the building and its earth electrode. The resistance of such earthing should not exceed 30?

kkas12 · Answer

I do not know what the authors (creators) of this document had, but its full title is:
N SEP-E-001 Networks low voltage power engineering. Electric shock protection. And the difference between a net and an installation is the same as between a fishing net and a fishing rod.
The electrician should distinguish this and not confuse other people.

jarecki 86 · Answer

As the requirements of the above-mentioned standard apply to both line distribution circuits and selected load circuits of electrical devices (operating at the grid-installation interface), some power plants, referring to these regulations, once ordered the PEN conductor to be grounded in overhead connection terminals. , mounted, for example, on the walls of single-family houses.
And because they were called protective and working earthing (with the required value up to 30 ohms), it was enough for a crowd of electricians to readily use this earthing for protection against electric shock. in the building.
Fortunately, these practices were discontinued shortly after, but as you can see from some entries on various industry forums, these activities left a mark on the minds of many electricians.

kkas12 · Answer

On my colleague, as I can see, the stigma of the new fashion has unfortunately also been imprinted.
What does it mean

Quote:
... working at the interface between the network and installations ...

Unfortunately, a colleague (and not only a colleague) does not see the difference between the fact that the power industry had (and has) an obligation to ground the "last pole" and it was a protective and working ground, not the one that the recipient makes under the building. And here is the reason for the 30 ?. But these are not "audience ohms", but EVs.
Is there anything unnamed between these two places (grounds)?

jarecki 86 · Answer

Let us forget about the last pole, because it is about the operational earthing in the TN network, made to ensure the correct operation of power devices in normal and disturbed conditions, and there is no mention of the protective function there. However, let's take another look at exactly what is written in the standard: And at this point, it is clearly about the contact between the supply network and the receiving installation. A colleague will admit that this conglomerate of words is not very fortunate, and even incorrect, as it can create a source of erroneous arguments for advocates of grounding the PEN breakpoint anytime, anywhere. And the most important thing is that this grounding should have no more than 30 ?

Current Standards for Earth Resistance in Detached Houses: Is 20 Ohms Acceptable?

Post #1

Post #2

Post #3

Post #4

Post #5

Post #6

Post #7

Post #8

Post #9

Post #10

Post #11

Post #12

Topic summary