Bit of earth help

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RustyH

Senior Member
Good Evening everyone,

This is off Picaxe topic, but Im just upgrading all the wiring in my garage (it was all very old and not very safe).

I have unfortunately found that there seems to be no earth connection in the garage at all :eek::eek:
The cable leading from the house to the garage is only two core armored cable (red and black.....old school)

Now with out quite extensive digging to replace the cable with 3 core, is there any other way I can go about achieving earth in the garage. Could I use an earth stake, or maybe use the steel Armour to link the earth of the house (not sure the latter is wise mind!!)
 
JimPerry

JimPerry

Senior Member
You will probably find that the armour was the Earth - a few years back I helped a friend replace a similar cable at his house in Cumbria - not easy :(
 
JimPerry

JimPerry

Senior Member
Wire-wool the armour and use a couple of Jubilee clips to attach a new Earth cable to your garage fusebox (you have got a fuse box, I hope) :confused:
 
R

RustyH

Senior Member
Thanks Guys, wasnt sure I could sure the armour, thats great news and saves me alot of worry.

Yup, Ive put in an RCD box :cool:
 
S

srnet

Senior Member
Are you sure this is not notifiable work under part P of the building regulations ?

In other words a legal requirement to have the re-wire inspected and tested to confirm that it meets current standards ?
 
G

g6ejd

Senior Member
One thing you should be aware of is the age of your property and whether it has a PME - Protective Multiple Earth installation, where there is no earth and you rely on the fact that your neutral feed is connected to an earth back at the power distribution transfromer for your road/street. For example you may typically measure a potential difference between your house (virtual) earth and a real earth. If you then add an earth at your garage, this could give rise to situations where lethal voltages can occur, especially (and usually) under fault conditions. If for example your neutral line was faulty, then your garage earth would become your neutral and that of a few other proprties too, giving you problems of electrical shock.

You should determine if you have PME, usually evident by all taps and pipes and heating systems having a visable earth, perhaps under the kitchen sink, an earth by the gas supply meter, etc together with earth leakage breakers. Be careful in adding an external earth if your house is PME - property ages of about (but not precisely) 1980 onwards.
 
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bluejets

Senior Member
g6ejd said:
One thing you should be aware of is the age of your property and whether it has a PME - Protective Multiple Earth installation, where there is no earth and you rely on the fact that your neutral feed is connected to an earth back at the power distribution transfromer for your road/street. For example you may typically measure a potential difference between your house (virtual) earth and a real earth. If you then add an earth at your garage, this could give rise to situations where lethal voltages can occur, especially (and usually) under fault conditions. If for example your neutral line was faulty, then your garage earth would become your neutral and that of a few other proprties too, giving you problems of electrical shock.

You should determine if you have PME, usually evident by all taps and pipes and heating systems having a visable earth, perhaps under the kitchen sink, an earth by the gas supply meter, etc together with earth leakage breakers. Be careful in adding an external earth if your house is PME - property ages of about (but not precisely) 1980 onwards.
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I think you may be getting confused with a different system as happens so many times when people comment on 1/2 known applications.

TN−C−S
Part of the system uses a combined PEN conductor, which is at some point split up into separate PE and N lines. The combined PEN conductor typically occurs between the substation and the entry point into the building, and separated in the service head. In the UK, this system is also known as protective multiple earthing (PME), because of the practice of connecting the combined neutral-and-earth conductor to real earth at many locations, to reduce the risk of broken neutrals - with a similar system in Australia being designated as multiple earthed neutral (MEN).

Sort of contradicts what you just said. Source here...... http://en.wikipedia.org/wiki/Earthing_system

RustyH,....get yourself an electrician. It is my experience that the people who end up getting "hung-up" on home-grown alterations are usually NOT the one who did the work but more likely one of the kids or the wife.
 
G

g6ejd

Senior Member
Well I have a lot of experience of what I refer to as PME in this property derived from my Amateur Radio equipment/antennas/earthing, there has been a lot written about the topic for those who want to read definitive guides from the IET rather than a wiki - whatever the system is called, I am just pointing out that in some UK properties, adding an external earth can lead to problems of electrical shock through apparently simple solutions.
 
J

jedynakiewicz

Senior Member
srnet said:
Are you sure this is not notifiable work under part P of the building regulations ?

In other words a legal requirement to have the re-wire inspected and tested to confirm that it meets current standards ?
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JimPerry said:
Wire-wool the armour and use a couple of Jubilee clips to attach a new Earth cable to your garage fusebox (you have got a fuse box, I hope) :confused:
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@Moderators: Liability issues?

I think that this forum is not the place for such discussions - srnet is correct, I understand that such work is notifiable in the UK. Whilst JimPerry's advice may not be at fault in principle, it is unlikely that the recipient would have the appropriate equipment to test and validate such work properly, given his apparent understanding of the topic.

I think that liability issues may arise for the moderators if the forum does not indicate that this is not the proper place for such advice/discussions as an improper installation would carry legal liability for the installer.
 
S

srnet

Senior Member
Indeed.

The installation would need to meet the (now) legal requirements for earth loop impedance too.

Not sure how you can advise its OK to use the cable armouring as the ground, unless you know how big the cable is and how long it is, and the OP did not say.
 
D

Dippy

Moderator
I agree.
I know a lot of things in life seem "common sense" and, in theory, easy - but there's more at stake.
OP's choice.
If there is an incident the last thing you want to put on the paperwork is "Well, that bloke on the Forum said...".
It's the 21st century version of "The bloke down the pub said hammer a nail into the ground...".

I think the best advice for anyone who has to ask is "Consult a qualified electrician".
Boring but safe.

PS. I was having a quick look on this Forum FAQs for statements re: liabilities and/or disclaimers - I couldn't find one. Ec?
 
J

Jeremy Harris

Senior Member
There's no liability issue for this forum, any more than there would be a liability issue for the landlord of a pub in which such a discussion took place. Sometimes I think there's a British disease, with people scaremongering and trying to make life far, far, more complex than it need be by seeking to invent rules and regulations to replace common sense (and the OP seemed to have enough common sense to understand the safety issues, to me).

The advice to consult an electrician is sound, but that shouldn't mean that any discussion of earthing, earth bonding, compliance with BRs or wiring regs should be prohibited. For example, there's already some confusion here between equipotential bonding (ensuring that exposed metal parts in a house, like pipes, taps, shower heads etc are at the same potential) and earth bonding (the provision of a low impedance earth connection to the house wiring). Household wiring isn't rocket science and anyone capable of working with a Picaxe circuit should be capable of reading and understanding the wiring regs (they are by no means difficult to understand). If you wish, it's easy enough (and not too expensive) to get yourself Part P accredited, then you can perfectly legally do any notifiable work yourself (I've done it, and frankly it was a doddle).
 
JimPerry

JimPerry

Senior Member
I was maybe a bit flippant - but I did check that he had a fusebox! When I last helped replace a defunct cable the source had old "Frankenstein" type fuse boxes. I just helped dig out the old and bury the new - and the local electrician replaced the fuseboxes etc.

Local electricians can also issue a test certificate - which you will need if considering selling your house. :(
 
J

jedynakiewicz

Senior Member
Jeremy Harris said:
Sometimes I think there's a British disease, with people scaremongering and trying to make life far, far, more complex than it need be by seeking to invent rules and regulations to replace common sense (and the OP seemed to have enough common sense to understand the safety issues, to me).
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Paradoxically perhaps, as I was the one who raised the aspect of liability in the first place, I rather agree with you in general. I absolutely agree that common sense is often challenged by unnecessary regulation. Nevertheless, speaking generically and absolutely without any inference upon any author within this forum or thread, my experience is that common sense is often in short supply these days - as evidenced by the majority of accidents and injuries taking place within the home rather than the workplace which is generally better regulated.

My concern is that this is a PICAXE forum - not a home electrics forum. If a forum is moderated then it may be assumed that the moderators have a duty of care. That may be regarded as ensuring that no post that is libellous, in breach of copyright, illegal in any manner etc. would be maintained. Likewise, if any post that contains advice that may be hazardous to human life is not moderated then the lawyers may become interested if any incident occurs. I certainly deprecate what I would deem to be the intrusive excesses of lawyers into "a sensible approach to life" but I am very aware that that is the environment we are living in.

Your advice to gain Part P accreditation is most sensible and appropriate; you clearly have an understanding of the issues that may not be so visible to others.
 
J

Jeremy Harris

Senior Member
JimPerry said:
Local electricians can also issue a test certificate - which you will need if considering selling your house. :(
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Not just electricians, your local authority BR dept can do this, as can your DNO (not that I'd recommend going to your DNO!), or you can get anyone who's Part P accredited to do it. I've found a few DIY'ers who've decided that getting Part P accreditation was worth doing since the change in the regs a few years ago; often these are folk like me who are undertaking a self-build and can see an advantage in being able to do a fair bit of the electrical work themselves. A neighbour did it simply because he wanted to be able to carry on doing DIY on his house when the regs changed, which is how I found out that it was possible.
 
J

Jeremy Harris

Senior Member
jedynakiewicz said:
My concern is that this is a PICAXE forum - not a home electrics forum. If a forum is moderated then it may be assumed that the moderators have a duty of care. That may be regarded as ensuring that no post that is libellous, in breach of copyright, illegal in any manner etc. would be maintained. Likewise, if any post that contains advice that may be hazardous to human life is not moderated then the lawyers may become interested if any incident occurs. I certainly deprecate what I would deem to be the intrusive excesses of lawyers into "a sensible approach to life" but I am very aware that that is the environment we are living in.
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Thankfully the law retains a bit of common sense! Under the law in England and Wales there would be no presumption that the moderators of an unrelated forum would be competent to know whether or not advice being given was sound or not. The issue of liability hinges upon competence, and what the court expects of a competent person. For example (and this is based on a true case), if I give my neighbour advice on changing the brake pads on his car, and subsequently the brakes fail and cause a serious accident, I cannot be held liable for the advice I gave, as, in law, I would not be considered to be a competent person (because I'm not a mechanic/motor vehicle technician). If I were a qualified mechanic/motor vehicle technician, then I could be found to bear some, but not all, of the liability, as then the situation would have changed and I would be deemed to be competent to give advice on servicing the brakes of a car.

The law surrounding liability uses common sense, as in simple terms the test for liability hinges on whether the person receiving the advice should have a reasonable expectation of it being correct. The definition of "reasonable" comes down to the view of the court on the day, it is not defined in law, but left to the jury (or judge) to decide for each case. The oft-quoted (and rather old) legal example is "what would an ordinary man on a Clapham omnibus think was reasonable?"
 
B

bluejets

Senior Member
Well, it seems ok to claim to be a professional "amature" and declare systems functional and so easy to do yet they cannot identify the system in use to begin with, so why not have a crack at being a lawyer.

My best advice is to repeat what I said before and stay away from any 220v systems.

Just to clarify, yes I am qualified, have been for 40 years and have to prove it every 5 years to the authorities.
 
P

Paix

Senior Member
Ah, well being an amateur armature (amature) is likely to put you in a bit of a spin as you generate both power and enthusiasm for the argument at hand.

230V in the UK, so here we have to be that extra 10V careful :)

Certainly not good to find that your nice shiny transceiver is providing the local earth connection through your local shack earth due to a local company supply fault.
 
J

Jeremy Harris

Senior Member
Paix said:
230V in the UK, so here we have to be that extra 10V careful :)
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Worth noting that the UK supply is usually set (at the local transformer tap) to be higher than 230 V. The UK has a slightly offset voltage from the rest of Europe, a bit of a fudge to get around having to change anything when we joined the EU and everyone had to harmonise voltage standards to better allow free trade. Most of Europe was 220 V, now it's 230 V +/- 6%, so actually 216.2 to 243.8 V. The UK is slightly oddball, because we were 240 V but are now 230 V +10%, -6%, giving a range of 216.2 to 253 V. This was done so that the UK could effectively stay at 240 V and yet, on paper claim to be at 230 V to comply with the EU harmonisation requirements.

It's worth noting that, with the popularity of photovoltaic installations on homes, it's likely that many homes in the UK will now be closer to the upper voltage limit during the day. My neighbour is on the same phase as my house and he fitted a fairly large PV array last year. Since then I fairly regularly see close to 250 V during sunny days on my household supply.
 
D

Dippy

Moderator
"bit of a spin" - haha, very good Paix.

It's good to know that bluejets is actually qualified in electrickery regs.
On many occasions you never know whether (weather) replies are coming from actual experts (like bluejets) or Google Experts.
 
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