Garage earth

[Pat H]

That's why we bury it :')

 

[Richard Burns]

Silver is more conductive than gold and harder so you can still have a quality "S"WA!

 

[Pat H]

Wouldn't that be AUWA for gold and AGWA for silver.
And I guess FEWA for Steel (or iron as the closest chemical I could find)

 

[Last plumber]

Possible. If you watch Mr JW, he gives a good explanation of types of supplies, 8.30mins for TN-CS, if you don't want to get too bored;

Thanks very much. I already know all that's in the vid but thanks for your help.
Question is, if the neutral was lost on the supply to the house, then the house would be in the same potentially dangerous state as the garage which is being fed from it. So, what's the difference and why are we bothered about the garage but not the house ?

Not sure I agree with this bit of the video. In the video, he explains about an extension cable supplying say, a caravan outside and that there being a greater possibility of loosing the neutral in that type of cable than there is in the type that is used in the main supply ( concentric), which is very true. However, as the extension cable from house to caravan or house to garage would still have a connection to earth ( if only neutral is broken in that cable or flex ), and that earth would still be connected to the main neutral at the main supply to the property. The problems would surely only arise if the main neutral was broken.

So, what's the point in going all out to create a TT at the garage just in case the main neutral is lost in some freak accident, yet not bother with the house it is being fed by.

In addition, Is there the possibility of different earth potentials being created with an earth rod ?
There are sub stations on my housing estate and a transformer on a pole at the rear of the property.
So if the house is fed from a transformer on the estate and I put an earth rod in the ground within 50 meters of the transformer on the pole, does that matter ?
I realise this is going on and getting deep so I apologise for dragging this out.

 

[Silly Sausage]

I realise this is going on and getting deep ...

As you seem to be really getting in your Earthing, here is some further reading for you.

 

[bigspark17]

Thanks very much. I already know all that's in the vid but thanks for your help.
Question is, if the neutral was lost on the supply to the house, then the house would be in the same potentially dangerous state as the garage which is being fed from it. So, what's the difference and why are we bothered about the garage but not the house ?

Not sure I agree with this bit of the video. In the video, he explains about an extension cable supplying say, a caravan outside and that there being a greater possibility of loosing the neutral in that type of cable than there is in the type that is used in the main supply ( concentric), which is very true. However, as the extension cable from house to caravan or house to garage would still have a connection to earth ( if only neutral is broken in that cable or flex ), and that earth would still be connected to the main neutral at the main supply to the property. The problems would surely only arise if the main neutral was broken.

So, what's the point in going all out to create a TT at the garage just in case the main neutral is lost in some freak accident, yet not bother with the house it is being fed by.

In addition, Is there the possibility of different earth potentials being created with an earth rod ?
There are sub stations on my housing estate and a transformer on a pole at the rear of the property.
So if the house is fed from a transformer on the estate and I put an earth rod in the ground within 50 meters of the transformer on the pole, does that matter ?
I realise this is going on and getting deep so I apologise for dragging this out.

Within the property this is why main equapotential bonding is essential to eliminate potential diference between suppliers earth and extraneuos conductive parts within property. Its no diferent to a shed!

 

[Last plumber]

As you seem to be really getting in your Earthing, here is some further reading for you.

Excellent. I'll read that. Thanks !

 

[Last plumber]

Within the property this is why main equapotential bonding is essential to eliminate potential diference between suppliers earth and extraneuos conductive parts within property. Its no diferent to a shed!

Thanks for coming back.
What I was thinking with the earth rod was :-
The neutral and internal earth ( in house), are combined at the point of entry to my property. The neutral is earthed at multiple points on the way back to the transformer where line and neutral come from.
So, if I'm using the neutral from the house and I put an earth rod in the ground which could be nearer ( and have less resistance) to the transformer on the pole at the rear of the property, does that matter ?
Or are you saying that all earth is potentially the same ?
I could be overthinking this and I won't be offended if you say so.

 

[Pat H]

There are recommendations on earth rod spacings related to transformers but beyond that earth is just earth. Having more "real" earth points just helps nail down your earths at 0V
The problem often is getting a really good earth via a rod. Wet weather is fine but a dry summer can cause higher resistance.
I'm in a similar position with a summer house 20M from my property and have decidede to use an 6mm CSA SWA plus use a local Earth rod as well.
The feed will have an RCD at the house end anyway. No metal at the summer house end but I intend to have a goid local earth anyway.

 

[Richard Burns]

In a house you are within an equipotential zone and unlikely to contact a different potential.
Outside the house it is more likely you will encounter differing potentials.
An earth rod local to the incoming supply can mitigate the PD on loss of PME neutral on TNCS but to make it safe (i.e. low touch voltages) the earth rod would need a resistance of (depending on load) about 5 ohms, which is difficult to achieve.
An additional rod (as opposed to a TT system) local to a remote installation may mean in the case of an open supply neutral that the house load is directed along the circuit earth to the remote rod and generate a significant potential vs earth.

 

[Midwest]

Just as an aside Last plumber, I take it from your title, you will be employing the services of a competent electrician to complete this work?

 

[Pat H]

Its no longer competent. It's skilled and trained. The competent person definition has been deleted in the current regs.
Mind you its still the competent persons scheme rather than the akill and trained scheme.

 

[Last plumber]

Just as an aside Last plumber, I take it from your title, you will be employing the services of a competent electrician to complete this work?

Don't be deceived by the title and never judge a book by its cover.
I am more than competent with electrical work, qualified to do the work I am involved in day to day and fully insured to do it.

I do however, like to do things belt and braces and in such a way that any engineer looking over my work, has no comment to make other than the positive.

The cable was installed through to the garage by a commercial spark with over 30 years under the belt and he passed it off through building control during the extension work.

whoever finishes it has yet to be decided, my concern at this moment is
How it is done. As you can see, there are differences of opinion on this, therefore, I will make an educated decision as to which is the safest method before anything else is decided.

Thanks for the concern though.

And thanks to all of you for your responses so far.

 

[Midwest]

Don't be deceived by the title and never judge a book by its cover.
I am more than competent with electrical work, qualified to do the work I am involved in day to day and fully insured to do it.

I do however, like to do things belt and braces and in such a way that any engineer looking over my work, has no comment to make other than the positive.

The cable was installed through to the garage by a commercial spark with over 30 years under the belt and he passed it off through building control during the extension work.

whoever finishes it has yet to be decided, my concern at this moment is
How it is done. As you can see, there are differences of opinion on this, therefore, I will make an educated decision as to which is the safest method before anything else is decided.

Thanks for the concern though.

And thanks to all of you for your responses so far.

I never judge a book by it's cover, I normally look inside and have a butchers at the preface. Unfortunately in your case, there is no information about your qualifications in your profile, hence me asking.

And I was only asking, as often persons post here, seeking a step by step guide to carry out electrical work. As you state you are qualified, you will have the knowledge, experience and suitable tools and test equipment.

You have confused me about who installed the cable; you state it was installed by a 'commercial spark', but in #19, referring to the csa of the swa, you said ' it was four years ago I ran it'. Normally any notifications to LBC are done when the work is completed and fully tested, you don't have to notify to run a length of cable?

My concern is genuine though. Of late I have seen far too many poor and unsafe electrical installations, carried by persons who were not or should not be deemed to be competent.

 

[Midwest]

Its no longer competent. It's skilled and trained. The competent person definition has been deleted in the current regs.
Mind you its still the competent persons scheme rather than the akill and trained scheme.

Thanks Pat H for correcting me. You are indeed right that BS7671 3rd Amendment, revised the definitions for 'Instructed persons (electrically) & Skilled persons (electrically).

However, I was using the adjective 'competent' to assess whether someone (no offence Last plumber) of having the necessary ability, knowledge, or skill to do something successfully.

 

[Last plumber]

I never judge a book by it's cover, I normally look inside and have a butchers at the preface. Unfortunately in your case, there is no information about your qualifications in your profile, hence me asking.

And I was only asking, as often persons post here, seeking a step by step guide to carry out electrical work. As you state you are qualified, you will have the knowledge, experience and suitable tools and test equipment.

You have confused me about who installed the cable; you state it was installed by a 'commercial spark', but in #19, referring to the csa of the swa, you said ' it was four years ago I ran it'. Normally any notifications to LBC are done when the work is completed and fully tested, you don't have to notify to run a length of cable?

My concern is genuine though. Of late I have seen far too many poor and unsafe electrical installations, carried by persons who were not or should not be deemed to be competent.

Ah, understood.
I will sort that at some point. Novice with these things I'm afraid. It took me all my time to put a profile picture on and I can't get that to line up properly. I also can't work out how to post pictures or links.

Yes to knowledge, experience tools and test equipment. I'm an industrial, commercial and domestic heating engineer with 28 years experience, although my electrical work is only related to heating.

I leave electrical installation issues outside that to the sparks I know.
And as far as earth rod testing, that too will be done by a pro with the right equipment.


The ' four years ago when I ran it ' bit, was a figure of speech. I built a large extension around my house four years ago. The commercial spark wired everything in the house and notified building control. I think it was actually his apprentice who dug a trench up the garden to where the garage is now. ( the garage wasn't there then ). The spark supplied the cable and I dropped it in. The spark tested and connected it and put a submarine joint box on the end in the garage. Everything was signed off at the time. I know you wouldn't sign just a cable run off. It was all done together is what I was meaning. In #19 I was avoiding rambling on through all the explanation by simply saying ' I ran it '.

With regard to your concerns, I understand and agree with you. It's only last year I discovered that one of my customers had had a new consumer unit installed. The electrician had left the house with no earth. He had made a mistake in connecting the earth from the consumer unit to the supply. I asked to see the certificate and was presented with all the correct papers. The readings on those were text book readings but the wrong ones. Had he tested his installation correctly, he would have spotted his mistake.

That electrician was NIC registered !

Very scary.