Earth rods

[Mudassar08]

Hello people!
Should earth rods be visible or in a enclosure with the box visible
I cant see mine anywhere TT system..

 

[Murdoch]

Are you sure you have one ?

 

[Mudassar08]

Are you sure you have one ?

I must have one because checking from earth to live i get reading on my multimeter but i cant find where it is

 

[Murdoch]

I must have one because checking from earth to live i get reading on my multimeter but i cant find where it is

that’s not the usual way to determine this

 

[Mudassar08]

that’s not the usual way to determine this

is it not? then if you have no rod then how will the meter display the voltage as there is no reference...?

 

[Murdoch]

is it not? then if you have no rod then how will the meter display the voltage as there is no reference...?

depending on the age of the property there might be cross bonding to the gas, or bonding to the water main

whats your Ze?

 

[Mudassar08]

depending on the age of the property there might be cross bonding to the gas, or bonding to the water main

whats your Ze?ze

116 ohms.

 

[Mudassar08]

I just need access to earth rod but i cant see it outside the property

 

[Murdoch]

I just need access to earth rod but i cant see it outside the property

why do you need to access it?

 

[Mudassar08]

why do you need to access it?

I need to know the condition of it as its probably rusted, neighbour of mine showed his to me and i was disgusted.

 

[Murdoch]

I need to know the condition of it as its probably rusted, neighbour of mine showed his to me and i was disgusted.

Follow the green & yellow cable from the fuseboard?

 

[Mudassar08]

Follow the green & yellow cable from the fuseboard?

Yes but my question is is there any other way to verify if you got 1 except from doing this way

 

[Murdoch]

Yes but my question is is there any other way to verify if you got 1 except from doing this way

Your Ze certainly suggests a TT system but it could easily suggest a poor TNS or TNCS connection too

Best you locate the rod ........

 

[Mudassar08]

Yep your right your right.
Whats your opinions about a tt with no rcd only mcb?

 

[Murdoch]

Yep your right your right.
Whats your opinions about a tt with no rcd only mcb?

C2

 

[poni]

What tests were done to prove that your water pipe was a good reference earth?

Otherwise you are trying to measure a suspect voltage on an unproven continuity CPC..
to a completely up-proven reference point?
Which I cannot see any sense or valid reason for doing?

In my book its either prove CPC continuity with dead tests first..
OR if you were trying to measure any suspect voltages..
get a long lead to use as a reference point back to the main-earth connection at the CU, or at suppliers connection point if accessible?

Any other methods of measuring random voltages are just pi55ing in the wind guessing at numbers for no practical purpose, to prove nothing!?

What are you trying to prove?
(a) Your meter can show random induced voltages?
(b) There is no continuous CPC connection back to the CU?
(c) Your CPC is good but the water pipe has an induced voltage?
(d) It's pointless trying to do random tests with the wrong meter because your other one was at home?
(e) Some unknown person in the past has connected "non-Class II" accessories onto pre 1966 lighting circuits?
(f) Other??

Follow this advice

 

[binky]

I just need access to earth rod but i cant see it outside the property

Might be under the floor, but often the cable and rod ( it might not be a rod) get buried in soil.

 

[Marvo]

With that kind of Ze reading the Ra of the actual rod on its own could be far higher so I wouldn't waste time trying to find it. You could spend hours searching so I'd rather spend the time just installing a new one and getting a better impedance value.

 

[SPECIAL LOCATION]

It sounds to me as though you probably need a competent electrician to call in and check the incoming supply characteristics to establish what the actual earthing arrangements are for the installation...

OR.. make enquiries with the DNO to see what they say the earthing arangements should be..
Earth rods are one method of providing an earth electrode. section 542, BS7671 gives guidance..

Also 411.5.3 does recommend the earth loop impedance should be as low as possible,
and that greater than 200ohms could be unstable, so 116ohms may not be the end of the world.

Although all joints should be accessible for inspection and testing...
I have been to numerous older properties where various "essential" connections have become buried, hidden or just inaccessible!!

I'm not convinced these types of investigations and/or testing are within the scope of most DIY'ers?

 

[MikeJhn]

As Marvo said sink in a new rod and be done with it, hopefully you have an SDS.