How do i test what earth reading i have in my sockets?

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chazkelly1985

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hi, i had a central heating engineer come round to install a new system, however when he checked the sockets he said i had a variable earth

i asked him how he got that reading and he didnt know - can anyone tell me how to check what reading you have on your earth on your sockets

 

Mr Sworld

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hi, i had a central heating engineer come round to install a new system, however when he checked the sockets he said i had a variable earthi asked him how he got that reading and he didnt know - can anyone tell me how to check what reading you have on your earth on your sockets
Well a 'variable earth' is a new term to me! I am presuming that he performed a Earth Loop Impedance test on the socket/fused connection outlet that supplies the boiler.

This test checks to see that the fuses/trips will operate within the required time to prevent electrocution.

To be honest someone who tells you that you have a 'problem' with your electrical system but cannot tell how they arrived at that conclusion is next to useless.

If you do feel concerned about it I would ask a local, reputable, electrician to perform a Periodic Inspection on your property. It'll cost you

 

chazkelly1985

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useless isnt the word

i had an electrition come round last night and he said the earth readings on my sockets were different

my house is pretty big with over 100 sockets and 3 fuse boxes

how do you test what earth reading you have on the sockets?

 

NWDS

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thats not ahouse thats a hotel or a mansion mr, get some one in who knows what they are doing,perhaps people on here might help if they know were you are at.

regards Iain

 

Flying Scotsman

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useless isnt the wordi had an electrition come round last night and he said the earth readings on my sockets were different

my house is pretty big with over 100 sockets and 3 fuse boxes

how do you test what earth reading you have on the sockets?
the reading will probably be different to the heating circuit because they arre different lengths of run for a start from the fuse board. the sockets are likely to be a ring main and the heating (if supplied seperately) will most probably be a radial

 

Quadzilla

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You test it by using of these, for example. you them compare the readings to ones within the BS7671:2008 Regulations book.

That is a short way of describing it. :)

 

SPECIAL LOCATION

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useless isnt the wordi had an electrition come round last night and he said the earth readings on my sockets were different

my house is pretty big with over 100 sockets and 3 fuse boxes

how do you test what earth reading you have on the sockets?
OK.. Hello chazkelly.... welcome to the forum,

Don't want to bombard you with technical bits...

But to provide any useful help.. we do need to discuss a few basic ground rules of electrics.

(first of all if there are any bits any of us have posted that you cant understand...

ask us to try and explain a bit better, it is very easy to make assumptions and miss a bloomin obvious point..

and go striding off in the wrong direction! :) So shout up if you cant get your head round what has been said)

Some key points shout out at me on this one..

1/ as Mr Sworld said..

To be honest someone who tells you that you have a 'problem' with your electrical system but cannot tell how they arrived at that conclusion is next to useless.
2/IMO what your electrician said is in the same category as point 1/ above

i had an electrition come round last night and he said the earth readings on my sockets were different
3/ BOTH observations 1 & 2.. SHOULD have been able to recommend some appropriate remedial action if they felt there was a problem?

did they suggest any improvements? or just walk away leaving you none the wiser?

4/ "the earth readings"

What exactly are these earth readings he/she is talking about..

i.e. a test reading must be done between at least two reference points to get a reading?

for example are we talking about:-

i) Earth loop impedance (as Mr S suggested)

ii) Long lead continuity of Earth conductor?

iii) Continuity of the earth on a ring circuit?

iv) Obviously it is a largish property with multiple boxes.. does it have Earth rods.. (more than one).. and they are saying the external earth loop impedance is high .. (also called Ze)?

5/Back to basic facts:-

Assuming we are talking about some sort of continuity problem..

Electrical continuity of a cable is measured using a thing called the "Resistance" which uses a measurement unit called the "Ohm".

If we are talking about your average type socket circuit wired in copper twin & earth PVC cable..

Each of the copper conductors, within the cable, have a know fixed "Resistance" per every meter of cable.

(there are reference tables in a book called the On-Site-Guide. Appendix 9).

So I know if you had a socket 20m along a piece of 2.5mm cable with a integral 1.5mm earth wire..

The earth wire would have a resistance of 0.242ohms from end to end of the cable.

or putting it another way... the earth wire will increase by '0.121 ohms' for every 10meters along the cable.

So because all of your sockets and outlets are at different points on the circuit...

the Resistance of the earth connection, will be different dependant upon whereabout on the circuit it is!?

Which is the long explanation of what Flying Scotsman says.

and coming back to if there is a problem or not...

these sort of continuity readings do have maximum permissible values to ensure your fuses or circuit breakers operate correctly!

AND any reasonably knowledgeable electrician should Know these basic concepts and IF there was a problem due to limits exceed? should be able to advise suitable action.

Whereas if they are saying there is a Loose connection and as they try and take a reading it is fluctuating..

then that still needs further investigation, i.e. is it a circuit? or the main earth to the property?

TBH IMHO..

it wouldn't be that hard, for a competent person on site, to be able to recommend any particular improvements based on their investigate findings.

Hope that hasn't fried your brains too much?

have beerGuiness Drink

and let us know if you have any further details or need better explanation! ;)

Where about in the country are you ? N,S,E,W,Middle???

 

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You test it by using of these, for example. you them compare the readings to ones within the BS7671:2008 Regulations book.That is a short way of describing it. :)
Thats very True Quadzilla..Applaud SmileyApplaud Smiley

And I've just done the long way of describing it! :eek:

so...

hopefully ALL bases are covered? :p :D:D

 
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useless isnt the wordi had an electrition come round last night and he said the earth readings on my sockets were different

my house is pretty big with over 100 sockets and 3 fuse boxes

how do you test what earth reading you have on the sockets?
Thats correct. I would be more worried if they were all the same ! A shorter answer to your last question is, You use a Earth loop impedance tester.

 

daryl631

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OK.. Hello chazkelly.... welcome to the forum,Don't want to bombard you with technical bits...

But to provide any useful help.. we do need to discuss a few basic ground rules of electrics.

(first of all if there are any bits any of us have posted that you cant understand...

ask us to try and explain a bit better, it is very easy to make assumptions and miss a bloomin obvious point..

and go striding off in the wrong direction! :) So shout up if you cant get your head round what has been said)

Some key points shout out at me on this one..

1/ as Mr Sworld said..

2/IMO what your electrician said is in the same category as point 1/ above

3/ BOTH observations 1 & 2.. SHOULD have been able to recommend some appropriate remedial action if they felt there was a problem?

did they suggest any improvements? or just walk away leaving you none the wiser?

4/ "the earth readings"

What exactly are these earth readings he/she is talking about..

i.e. a test reading must be done between at least two reference points to get a reading?

for example are we talking about:-

i) Earth loop impedance (as Mr S suggested)

ii) Long lead continuity of Earth conductor?

iii) Continuity of the earth on a ring circuit?

iv) Obviously it is a largish property with multiple boxes.. does it have Earth rods.. (more than one).. and they are saying the external earth loop impedance is high .. (also called Ze)?

5/Back to basic facts:-

Assuming we are talking about some sort of continuity problem..

Electrical continuity of a cable is measured using a thing called the "Resistance" which uses a measurement unit called the "Ohm".

If we are talking about your average type socket circuit wired in copper twin & earth PVC cable..

Each of the copper conductors, within the cable, have a know fixed "Resistance" per every meter of cable.

(there are reference tables in a book called the On-Site-Guide. Appendix 9).

So I know if you had a socket 20m along a piece of 2.5mm cable with a integral 1.5mm earth wire..

The earth wire would have a resistance of 0.242ohms from end to end of the cable.

or putting it another way... the earth wire will increase by '0.121 ohms' for every 10meters along the cable.

So because all of your sockets and outlets are at different points on the circuit...

the Resistance of the earth connection, will be different dependant upon whereabout on the circuit it is!?

Which is the long explanation of what Flying Scotsman says.

and coming back to if there is a problem or not...

these sort of continuity readings do have maximum permissible values to ensure your fuses or circuit breakers operate correctly!

AND any reasonably knowledgeable electrician should Know these basic concepts and IF there was a problem due to limits exceed? should be able to advise suitable action.

Whereas if they are saying there is a Loose connection and as they try and take a reading it is fluctuating..

then that still needs further investigation, i.e. is it a circuit? or the main earth to the property?

TBH IMHO..

it wouldn't be that hard, for a competent person on site, to be able to recommend any particular improvements based on their investigate findings.

Hope that hasn't fried your brains too much?

have beerGuiness Drink

and let us know if you have any further details or need better explanation! ;)

Where about in the country are you ? N,S,E,W,Middle???
flipping eck did you have to replace keyboard arter writing war and peace] :)

 

Admin1

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I reckon that he has pre-typed his posts, saved them, and when someone asks a question - he just clicks the "Reply" button, Goes for a Meal and a coffee, we think that he is busy typing away - then he comes back - copies and pastes his previously typed post.

I bet he types more words per minute, than an experienced secretary

 
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