# Interest group forums > Electrical Contracting Industry Forum >  SANS codes.

## I Robot

I see the SANS codes are not available online.

Would an online version of SANS 10125 be useful. I can see about loading them and keeping them up to date. It would also be searchable, which might prove useful.

Any comments.

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## Nicky

Of course it would be useful!  Absolutely!  It would also be an excellent idea if you highlighted new regulations as soon as they are applicable.

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## Jacques#1

....Just make sure the one you post is not the version you pay for in the store  :Smile: ...it may upset a few guys up at SABS if you know what I mean.

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## AndyD

> I see the SANS codes are not available online.
> 
> Would an online version of SANS 10125 be useful. I can see about loading them and keeping them up to date. It would also be searchable, which might prove useful.
> 
> Any comments.


How deep did you rummage? This is a link to a torrent file that looks promising, here's a few of the codes contained within;

*Edit;* If you're not sure what to do with the torrent file send me a pm and I'll show you how.


ACI-318-02 Building Code Requirements For Structural Concrete.pdf 
ANSI EASA Standard AR100-2001 Recommended Practice for the Repair of Rotating Electrical Apparatu.pdf
Construction Standards for Small Vessels.pdf
Gold Coast SS12_StandardSpecifications2006[1].pdf
Haccp/9cfr417haccp.pdf
International Building Code 2006.pdf
ISO_9000'2000_An_A-Z_Guide.pdf
ISO_9000_Quality_Systems_Handbook_4E.pdf
LEED FAQ's.pdf
LEED_CI_2.0 REFERENCE GUIDE/CI Scorecard.xls
LEED_CI_v2.0_GUIDE.pdf
LEED_EB_v2.0_GUIDE.pdf
LEED_NC sample test.pdf
LEED_NC_scorecard_version_2_2.xls
LEED_NC_V2.2_GUIDE.pdf
National Electrical Safety Code Handbook
NEMA ICS 19 (2002).pdf
Portable Oxy-Fuel Gas Systems For Welding (Australian Standards).pdf 
South Africa National Building Regulations SANS 10400
SANS10086-1.pdf
SANS10086-3.pdf
SANS10089-2.pdf
SANS10108.pdf
SANS10123.pdf
SANS10142-1(Amdt2).pdf
SANS10142-1.pdf
SANS10313.pdf
SANS60079-0.pdf
SANS60079-10.pdf
SANS60079-19.pdf
SANS61024-1-1.pdf
SANS61024-1-2.pdf
SANS61024-1.pdf
SANS61241-1.pdf
SANS61241-10.pdf
SANS61241-4.pdf
BY-LAWS RELATING TO ELECTRICITY SUPPLY.pdf
coc for electrical installations.pdf
CODE OF CONDUCT DESIGN AND CONSTRUCTION OF COLDSTORE.pdf
ELECTRICITY BY-LAW, 20.pdf
Emergency_lighting_Guidelines.doc
HEATED TOWEL RAILS- INSTALLATION IN THE BATHROOM.pdf
IEC600~1.PDF
IEC600~2.PDF
IEC600~3.PDF
OCCUPATIONAL HEALTH AND ASFETY ACT.pdf
Regulation - 2920 - OHS - Electrical Installation Regulation.doc
2007 Edition 2 Induction motors Part 1 IEC requirements.pdf
2007 Edition 1.4 Part 2 Low-voltage three-phase standard motors.pdf 
Guide for the design and performance of cage induction motors .pdf
identification and classification of dangerous goods for transport.pdf
SANS10142-1 Amendment No. 5.pdf
SANS10142-1(Amdt2).pdf 
SANS10142-1(Amdt3).pdf 
SANS10142-1(Amdt4).pdf 
The rewinding and refurbishing of rotating machines 3-phase.pdf
SANS10~2.PDF
Rewound and refurbished rotating electrical machines.pdf
SANS60269-2(IECamdt2)SUPPLEMENTARY REQUIREMENTS FOR FUSES.pdf
Surge Protection in Low Voltage Electrical Installations.pdf
The RS-232 Standard .pdf

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Dave A (03-Feb-10)

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## 123

https://www.sabs.co.za/index.php?page=standardspurchase

You can buy directly from sabs.

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Dave A (17-Mar-10)

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## wynn

Post as many as you can in a wiki, never know when you may need one.

 :Big Grin:

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## murdock

these would be very interesting threads.

if we could get hold of some past exam papers and post a question on the site per day then people could answer or assisst with understanding the code better...now that would be a good idea...it would be like a refresher course for some of us ....help with people doing the course and and at the same time make the public more aware of the codes and what is expected of electricians... :Thumbup: 

i purchased the code on cd but never updated.

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## murdock

and to make it more interesting add in some practical experiences from the inspectors....for example

while carrying out a inspection report...you come across a DB while is higher than 2.2 m above the ffl what action do you take and what would the recommendation be to solve this issue. (common problem encountered)

do you leave it as is and sign over the coc or do you lower the main switch to below 2.2 m.

another common one is the db in the cupboard...what do you do.

so now you buy a property and walk in the kitchen and find the db in the cupboard...if you are not an electrical inspector by reading these post you will know what to expect and if the inspector has been on the property.



the tv guy comes to fit you arial...what to expect...who puts the earth wire...and where do you connect it...all these type of question related directly to the public...it would make the public more aware and hopefully more people will take the time to contribute...or query installtions by posting pic of their queries.

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## Jacques#1

Ive got one too.......  The new ammendment requires surge arrestors be installed in the house.  They make reference to this on multiple pages, including a dedicated annexure (L).

What do you do if there is no more space in the DB??????????????

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## 123

_6.7.6 Surge protection
6.7.6.1 Surge protective devices (SPDs) may be installed to protect an
installation against transient overvoltages and surge currents such as those
due to switching operations or those induced by atmospheric discharges
(lightning). Amdt 1; amdt 6_

Hi Jacques, do they mean "may be installed"? which does not not mean "must be installed"?

Regards-Christo

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## murdock

this is what i was hoping for...constuctive critism.

dave its time to scrap the generator thread and turn it into the sans code thread :Big Grin:

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## Dave A

I'll be honest - it's exactly this type of interpretive discussion I've been hoping to see a lot more of on this forum.

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## Jacques#1

If you read Annexure L 1.2.1 Pg325 "Surge protection devices shall be installed at least in the main distribution board of an electrical installation"

I also read the "may" part, but then remembered two things:

1. An inspector once told me that the book may not always make sense, or there may be double standards, you have to interpret it in the safest reasoning possible.....so if you get a part that is "safer" than a contradicting statement somewhere in the book you must go with the "safer" option.  This according to him will convince a judge in court that you were reasonable with the best and safest intentions.

2. On the ECA roadshow they discussed the changes.  They talked about SPD's and the guy said for JHB its a no brainer, we have guy fox up here every second night with all the lightning, and supply is a problem every once in a while.  He then also talked about CPT, said that the CPT guys said they never get lightning, showed a picture of this massive lightning bolt hitting close to table mountain (everybody laughed).....but more problematic is the CPT supply problems as I understand it.

Point is, theres a part in the code that says I must install it, and every new house/COC I do I install it.  If you are doing a big complex the engineer specifies SPD's at every split in the electrical system.  The main SUB, Mini SUb, Block subs and the flat subs.

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## Jacques#1

> and to make it more interesting add in some practical experiences from the inspectors....for example
> 
> while carrying out a inspection report...you come across a DB while is higher than 2.2 m above the ffl what action do you take and what would the recommendation be to solve this issue. (common problem encountered)
> 
> do you leave it as is and sign over the coc or do you lower the main switch to below 2.2 m.
> 
> another common one is the db in the cupboard...what do you do.
> 
> so now you buy a property and walk in the kitchen and find the db in the cupboard...if you are not an electrical inspector by reading these post you will know what to expect and if the inspector has been on the property.
> ...


I'll answer these....I know you just made a statement and know these answers but...questions since someone may be reading them right now and wanting to know the answer :Smile: ?  

1. As far as I know you can do an industrial jobbie on the main switch.......take a 1.5mm stainless steel rope, ferrule it around the switch, make the bottom end lower than 2.2m, loop it and ferrule it.  Add a sign on the rope (switch off this main switch in the event.......), and one on the DB.

2.  Db in the cupboard, put a lable on the cupboard door stating the DB is inside the cupboard, and must remain un-obstructed.  Take a photo of the lable and you are set :Big Grin: .  (We all know the home owner pulls that ugly lable off before you turned on you ignition).

3.  The TV guy should put an earth wire, some does others don't.  They should also adhere to any standards related to their industry, regardless of its origin.

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## 123

_Annex L.1
(normative where surge protection 
is required or installed (see 6.7.6))_ 

It *may* be installed, and if it *is* installed, it *shall* be at least in the *main db....*

Thanks Jacques, I see your point.

I was more thinking as a requirement in order to validate a coc.

Is it a requirement then? Should the issuer of the coc install it if it is not present?

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## Jacques#1

> _Annex L.1
> (normative where surge protection 
> is required or installed (see 6.7.6))_ 
> 
> It *may* be installed, and if it *is* installed, it *shall* be at least in the *main db....*
> 
> Thanks Jacques, I see your point.
> 
> I was more thinking as a requirement in order to validate a coc.
> ...


Well, as I see it, it is a requirement, and I install it before I sign the house off.  I actually carry stock of CBI L+N 5kA SPD's (cheaper than 2 x single pole units), and 6mm gp wire.  If no-one can without a shadow of a doubt tell me that it is not required I'll rather not take the chance, and see it as the safer option?  Maybe someone will read this and comment with a more definitive answer?

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## 123

_1.3 Where this part of SANS 10142 is not applicable
This part of SANS 10142 does not apply to
a) electric traction equipment,
b) automotive electrical equipment (excluding the caravan part of a
roving vehicle),
c) electrical installations on board ships,
d) electrical installations in aircraft,
e) electrical installations for underground and open cast mining
operations,
f) telecommunication, television and radio circuits (excluding the power
supply to such equipment),
g) lightning protection of buildings and structures, and
NOTE The installation of surge protection is not compulsory, but where it is
installed, compliance with annex L is required. Amdt 1; amdt 5
h) extra low voltage control circuits between different parts of machinery
or system components, forming a unit, that are separately installed
and derived from an independent source or an isolating transformer
(excluding ELV lighting circuits). Amdt 5_

I think this should clear it up?

Note of interest: television circuits? does this include the antenna? is the antenna part of the signal circuit?

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Jacques#1 (19-Mar-10)

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## Jacques#1

> [I]1.3 Where this part of SANS 10142 is not applicable
> 
> [B][U]NOTE The installation of surge protection is not compulsory, but where it is
> I think this should clear it up?
> Note of interest: television circuits? does this include the antenna? is the antenna part of the signal circuit?


I yield, it looks like that specific part may indicate that SPD's is not required.  Now, try explaining this to an inspector (they don't exist in the old format anymore....now AIA's).......I've had an hour long debate with two inspectors about the definition of space heating.....and references to underfloor heating a few pages further :Smile: .

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## AndyD

> 1. As far as I know you can do an industrial jobbie on the main switch.......take a 1.5mm stainless steel rope, ferrule it around the switch, make the bottom end lower than 2.2m, loop it and ferrule it.  Add a sign on the rope (switch off this main switch in the event.......), and one on the DB.


I think you would need to be careful with loose or hanging type of arrangement that it would not present a 'contact' hazard if the door is opened.



> 2.  Db in the cupboard, put a lable on the cupboard door stating the DB is inside the cupboard, and must remain un-obstructed.  Take a photo of the lable and you are set.  (We all know the home owner pulls that ugly lable off before you turned on you ignition)..


This has always been a problem area especially with domestic installations. Knowing damn well that any labels are destined for removal and that the cupboard will be cluttered in a week means that in the event of an accident, a certain amount of liability would be on the shoulders of the issuer of the certificate surely. Maybe a firm rule of no DB's  in cupboards would be better.



> 3.  The TV guy should put an earth wire, some does others don't.  They should also adhere to any standards related to their industry, regardless of its origin.


Apart from the earthing requirement, the TV dish or antennas would not fall under the electrical COC. The earthing should be removed from the electrical regs in my view and made a part of the TV installation regulations. I think they included it in the electrical regs as a cop-out rather than trying to enforce good TV installation practices.




> _Annex L.1
> (normative where surge protection 
> is required or installed (see 6.7.6))_ 
> 
> It *may* be installed, and if it *is* installed, it *shall* be at least in the *main db....*
> 
> Thanks Jacques, I see your point.
> 
> I was more thinking as a requirement in order to validate a coc.
> ...


If I remember rightly, in one of the amendments surge protection was made compulsory then in a later amendment there was some backtracking and it was made discretionary. In some areas of Cape Town it might not be necessary, on the very few new installations we get involved in we include it in quotations but if price is an issue it's often the first thing to go.

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## Dave A

> If I remember rightly, in one of the amendments surge protection was made compulsory then in a later amendment there was some backtracking and it was made discretionary.


That's how I remember it too.

 :Hmmm:  Which makes a wiki based guide that highlights the "debatable" points and code changes a good idea, come to think of it. Then with each update we can edit the relevant page if affected and update the "changes" page.

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## murdock

this is what i like to see...tell us more about the space heater dicussion.

i will make a point of updating my sans book and get more involved in the discussion.

surge protection was engforce a couple of years ago then they scrapped it and now only if it is a high risk area it is required.

i agree with the DB in the cupboard but being a contractor and inspector...i have been involved in too many projects where customers have requested the cupboard be installed over the DB...most times you cant even ge tthe cover off...but to move it can be a huge job.

All DBs should be installed in the passage behind the passage door...it is the most practical place...nothing gets put in front of it...it is easily accessable from most places in the house...and by just closing the door you have full access to it...and if you mount it at a reasonable height you can put a picture over it...which can be removed to do work.

tv aerial earth should be installed by the aerial installer...but then the earth bar should be accessable in the roof...their argument is they cannot open the DB because they are not qualified to do so...and i agree...an earth bar in the roof could be of great assistance to everyone for geyser bonding...tv aerials...etc.

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## 123

Guys, let's put this one to bed, and kiss it goodnight. SPD's is NOT required for a valid CoC.

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## 123

Apologies, but the general interpretation of SANS 10142 1.3 (f) is: Excluding TV circuits... (pse read).

 Since "Television Circuits" , which most definitely includes the antenna, is excluded from "this part of sans 10142 -1" ... it is a no brainer. sans 10142 does not apply.

Or am I wrong?

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## AndyD

> tv aerial earth should be installed by the aerial installer...but then the earth bar should be accessable in the roof...their argument is they cannot open the DB because they are not qualified to do so...and i agree...an earth bar in the roof could be of great assistance to everyone for geyser bonding...tv aerials...etc.


Why can't they install a separate earth spike for the antenna?




> Guys, let's put this one to bed, and kiss it goodnight. SPD's is NOT required for a valid CoC.


As far as I know they're not a requirement but I would wait for better consensus on this if I were you.

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## murdock

the spike in the ground would be great but imagine tv people doing ground resistance tests...i cant see it happening...another test...better for the electrician to supply an earth point...just getting them to fit an earth will be a challenge on its own...still having to put in earth mats etc i cant see it happening...unless of course you add a hefty fine if not installed...i like the way the people who cut off hands for stealing do things...you dont see tooo many people walking around with no hands.

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## murdock

thanks for the link to sans..

just the fact that we are discussing sans is a step in the right direction...now we just need to get more people involved so that different views on various subjects can be discussed and practical issues being experienced...then all we need is to get the whos who in decision  making at sans to hear what the contractors are experiences in the field...who knows there might still be hope for this industry.

regardless of any of the guidelines mentioned in the sans book...there is one important factor...did you take apropriate steps to ensure the safety of humans and animals whether it be guide lines form sans book or justu use  plain old common sense....becuase the next question will be...with your experience and qualifications why did you not take apropriate action as required to protect them if you believed it was unsafe.

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## Dave A

> regardless of any of the guidelines mentioned in the sans book...there is one important factor...did you take apropriate steps to ensure the safety of humans and animals whether it be guide lines form sans book or justu use  plain old common sense....becuase the next question will be...with your experience and qualifications why did you not take apropriate action as required to protect them if you believed it was unsafe.


Which brings us to earth leakage units on plug points - how can anyone sign off an installation as reasonably safe without an earth leakage unit covering the plug points, just because the installation is older than a certain date?

We know better and have the equipment available nowadays - so why must we be obliged to accept outdated safety standards?

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## murdock

i agree with you 100%...i ended up buying one of the houses i did a coc for...at the time of inspection there was no e/l unit fitted...i signed over the house and wrote on the coc in bold letters...i would strongly advise an e/l unit is fitted.

i ended up buying the house...what do you think the first thing i did...fitted an e/l unit.

the reason...20 years ago i moved into a house which had no e/l unit...i had to replace a plug socket...so i went to the DB and switched off the plug circuit...assuming it was the correct circuit i removed the cover and grabbed the plug to pull it out because the wires where a bit short...because of the way i was holding it i didnt get thrown clear instead i was pulled against the wall...and stayed there for a period of time...god must have had other plans for me because i couldnt get myself loose and stayed there until i fell over which released me...i can still remeber that day like it was yesterday...it is a horrific experience.


my advice to anyone who has not got an e/l unit on the plug circuits no matter how old the house have one fitted asap...especially if you are an electrician...because that is always where the worste accidents happen because you think you are too smart and tooo relaxed when you work on your own property.

an earth leakage is a "personal protective device"...designed to protect human beings from electricution...not stop fires as some people think.

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## AndyD

At the risk of kicking a hornets nest, I'm in two minds about earth leakage breakers. Even if you get a shock off a system that's protected the time for the unit to disconnect is long enough to defibrilate you and possibly cause heart failure. If having an earth leakage installed makes people less concerned about getting shocks it could actually be a counter-productive measure.

Under normal circumstances to get an electric shock from an appliance you need two separate faults simultaneously and the person to be in contact with the appliance chassis at the same time. Firstly there needs to be a low-insulation fault which providesa path for current flow between the live wiring and the chassis. Secondly there needs to be a missing or poor earth which means there's no low resistance path for this fault current to safely flow. 

If it was a choice between having an earth leakage fitted to an installation and having all your appliances tested twice a year, I think the latter option might result in less deaths from electric shock.

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## Dave A

> At the risk of kicking a hornets nest, I'm in two minds about earth leakage breakers.


More like stepping into poo  :Stick Out Tongue: 
Let's see if we can get you off the fence on this one  :Big Grin: 



> Even if you get a shock off a system that's protected the time for the unit to disconnect is long enough to defibrilate you and possibly cause heart failure.


If 20-30 mA is enough, then that's always going to come down to the path the current takes. (I thought it takes about 50-100 mA, but I suppose that it will vary according to each person's own constitution).

I'd far rather have protection that's going to automatically kill the juice within a fraction of a second than get hooked up and have to wait for blind luck to take a hand, or for someone to realise there's a problem and kill the supply.



> If having an earth leakage installed makes people less concerned about getting shocks it could actually be a counter-productive measure.


Valid comment, but I think people are too blasÃ© about electricity already. Consider the "if it works, it's fine" attitude test inspectors get from their clients. Ultimately, it's hard to see people becoming more casual about it than they are already.



> If it was a choice between having an earth leakage fitted to an installation and having all your appliances tested twice a year, I think the latter option might result in less deaths from electric shock.


Testing an earth leakage unit is far simpler, and how often do people do that?

I think extending the earth leakage protection debate to appliances is a bit tricky anyway. That takes us right into the "everthing on earth leakage regardless" scenario. Plug points are a special risk zone, I reckon, as they present a number of problems and risks you shouldn't be getting elsewhere, particularly when it comes to reliable earthing.

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## Jacques#1

The rope DB thing:  We used to install the SS chain in DB's where lowering the DB is just not possible.  What is safer, doing joints on the cables because they are too short or fitting the chain?  As far as cost go its also just too expensive fitting seperate ciruits like a mains outside the DB (since most db's are flush mounted).  I started my electrical career at an explosives and chemical manufacturing facility, where I learned the SS rope thing.  Think of any electrical standard......they doubled it.  If 1 Mohms is good enough for SANS, they said 10Mohms etc.

The DB in a Cupboard:  The unfortunate part of the DB in cupboard as wrong as it may be, no-one will give you permission to dismantle their cupboard.  The argument that I've heard more than once when telling people its not really ideal/right, is, we bought the house like this, the house was built like this.

Bonding an antenna:  As the word may could possible exclude SPD's from an installtion, Page 186, 6.13.2.3 says "An antenna (including a satellite dish) shall be bonded to the installation earthing system by means of a conductor of at least 2.5mm2 copper or equivalent".  This piece says SHALL.

The Space heater:  The argument went around Page 199.  Note 2  talks about the appliances for space heating, and  6.16.4.1.2 talks about space heater.  We eventually agreed that a "Space Heater" regardless of the interpretation is actually an infra red or element heater that normally fits on a wall (thats where the out of arms reach bit comes in).  And a heater that heats a space i.e. its generally doing space heating.  Hope this makes sense......I don have a better way to discribe it?   Why is this important you ask..... A space heater shall have its isolation in the same room/or on the appliance.  If underfloor heating fell under the same category, it would have meant that installing a double pole CB in the db which is lockable and marked and under the safe principles of a fixed appliances would not have been allowed  :Smile: .  Since I was working in the underfloor heating industry, it affected my customers that could not get a COC because there was no Isolator in the same room.  Installing a 2xCB in the DB was ideal....

Fitting an E/L:  If SANS relaxed a bit as far as old (1992) and new installations go we would get more done.  Installing a new EL means a change to the electrical system, which in turn means the system has to comply to SANS 10142.  Replacing items as I see it is not a change in the system.  If SANS said.....you can install a E/L, it does not mean that the system is all of a sudden post 1992, more people would do it as its not going to cost an arm and a leg.  I too inform people, but they argue that if it was only installing a new EL they would do it, because its ten other things as well once the new EL is in, no way.....?

Thats enough for one day..... :Smile:

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## 123

> Bonding an antenna:  As the word may could possible exclude SPD's from an installtion, Page 186, 6.13.2.3 says "An antenna (including a satellite dish) shall be bonded to the installation earthing system by means of a conductor of at least 2.5mm2 copper or equivalent".  This piece says SHALL.


Hi Jacques, if i thought i was confused, i was mistaken. I am confused :Stick Out Tongue: 

We have, in our area, 12 MIE's, registered. One of which marks the IE exams. Another the ecb representative. I have clarified this with some of them (incl. Mr x which marks paper 1 and 2), on numerous occasions, and the consensus was that it is not required according to SANS 10142 (1.3) (f) on page 21 of the new sans 10142 from sabs.co.za.

Their argument being that the "equivalent" part", as stated in 6.13.2.4, is preceded by 6.13, which refers to "note 2":   ""NOTE 2 No external conductor is required if compliance with the requirements for continuity can be proved by the test in 8.7.2.""

Which means: _8.7.2 Continuity of bonding Amdt 4
Test the continuity of the bonding between the consumer's earth terminal
and all exposed conductive parts using a supply that has a no-load d.c. or
a.c. voltage of 4 V to 24 V, and a current of at least 0,2 A. In each case,
the resistance shall not exceed 0,2 Ω. Amdt 4_

Which means, if you have tested for the values, it would have indicated if a separate earth was needed. (Cost implications)

Regards - Christo
 :Surrender:  :Surrender:

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## AndyD

> More like stepping into poo


*(nods)*




> If 20-30 mA is enough, then that's always going to come down to the path the current takes. (I thought it takes about 50-100 mA, but I suppose that it will vary according to each person's own constitution).


The figure of 20_30mA you quoted is the leakage current that starts the tripping process of the earth leakage breaker or RCCD. As with any disconnect device there is a time between the start of the fault current being over the tripping threshold and the disconnection of the supply. During this window of time the fault current flows uninhibited by the disconnect device. In the case of an earth leakage current through a person receiving a shock this current would be determined by the resistance of the path to earth through the person. This resistance would very depending on a thousand and one variables such as footwear being worn, flooring surface, etc. If the person is touching an earth with the opposite hand they have contacted a live supply then this current would be large and particularly prone to causing defibrilation. The path of current flow would be across the chest.




> I'd far rather have protection that's going to automatically kill the juice within a fraction of a second than get hooked up and have to wait for blind luck to take a hand, or for someone to realise there's a problem and kill the supply.


Point taken. What I'm questioning is how effective at saving live these devices are. Are they saving more lives than compulsory appliance testing would be saving. Are they giving people a false sense of security causing them to work live instead of isolating etc. I would like to see some hard figures on how much higher survival rates are with shock victims if an earth leakage breaker is installed.




> Valid comment, but I think people are too blasÃ© about electricity already. Consider the "if it works, it's fine" attitude test inspectors get from their clients. Ultimately, it's hard to see people becoming more casual about it than they are already.


I think you would be surprised at the depths of some peoples stupidity :-)




> Testing an earth leakage unit is far simpler, and how often do people do that?


 Good point. Appliance testing would need to be legislated. It might be more appropriate for commercial premises where people have a more 'devil may care' attitude toward the machinery and appliances.




> I think extending the earth leakage protection debate to appliances is a bit tricky anyway. That takes us right into the "everthing on earth leakage regardless" scenario. Plug points are a special risk zone, I reckon, as they present a number of problems and risks you shouldn't be getting elsewhere, particularly when it comes to reliable earthing.


I think plug in appliances are more likely to suffer damage that may result in user shocks due to their mobile/portable nature. How many times have you seen a steam iron or lawn mower with a damaged trailing cable compared to a static appliance such as a geyser? These kind of faults are protected against already by the earth leakage breaker supplying the plug points.

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Dave A (23-Mar-10)

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## Jacques#1

> Which means: _8.7.2 Continuity of bonding Amdt 4
> Test the continuity of the bonding between the consumer's earth terminal
> and all exposed conductive parts using a supply that has a no-load d.c. or
> a.c. voltage of 4 V to 24 V, and a current of at least 0,2 A. In each case,
> the resistance shall not exceed 0,2 Ω. Amdt 4_
> 
> Regards - Christo


I fully agree with that.  The thing is, if you test the continuity by connecting one lead to the earth bar in the db, and the other on a geyser, the reading must be less than 20 Ohms (i think), so too for all continuity of bonding.  If you stick the tester on the DSTV aerial and the reading is say 10 Ohms, then  :Thumbup: .  I remember talking to an inspector about this.  He said it is not so much the lightning, rather the voltages the decoder gives off.  Have you ever touched the cable coming out of the decoder?  Sometimes that thing really bites you.  I haven't yet tested an aerial that passes, maybe I will get one and reduce the time I spent on site.  

PS... They talk about bringing it down to the earth continuity of the system.....I don't see this as taking the cable all the way to the DB, but rather any earth point that passes less than 20Ohms, like the geyser bonding, or a junction in the roof with space for one more earth. Don't take my word on this one though, I may be wrong.

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## Dave A

> I remember talking to an inspector about this.  He said it is not so much the lightning, rather the voltages the decoder gives off.


That inspector might want to consider the floating earth situation that could arise in a lightning strike if the earths aren't directly connected to each other.

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## AndyD

> Have you ever touched the cable coming out of the decoder?  Sometimes that thing really bites you.


There may be voltages present on the inner conductor of the antenna cable but the outer braided shield should be at 0 volts (earthed). The decoder or DVD player etc that the antenna cable plugs into won't earth the braided cable shield because most of this type of appliance are of such a class that an earth isn't required and they only have a two core electrical supply cable with no earth bond to the electrical installation. If the antenna cable gives shocks from the braided shield then the decoder could have a low insulation fault.

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## I need help

I have recently done a course,and believe it is now compulsory to install an auxillary earth terminal(bar) for "others",therefore the installation does not comply without this auxillary earth bar.
To be installed and indicating it is an earth bar (earth sticker,label)

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## Jacques#1

> I have recently done a course,and believe it is now compulsory to install an auxillary earth terminal(bar) for "others",therefore the installation does not comply without this auxillary earth bar.
> To be installed and indicating it is an earth bar (earth sticker,label)


That earth bar is usually located at the main entry point of the house.  (most new houses.....its at the ripple junction).  If there is a free standing bolt and nut in the box, its an earth stud, AKA earth bar.  :Smile:

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## Jacques#1

> That inspector might want to consider the floating earth situation that could arise in a lightning strike if the earths aren't directly connected to each other.


What I meant was....you connect the wire any other place in the earth system on the same grid, not install a new and seperate spike for this.  Besides, spikes are not really recommended anymore, you are only allowed to spike if you have no other choice (as far as I know)?

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## Dave A

My turn to explain - my point was around what the real hazard is...

I've got a door handle in my office that hands out a fairly dramatic static jolt from time to time, but hasn't killed anyone yet.  :Wink:

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## AndyD

> My turn to explain - my point was around what the real hazard is...
> 
> I've got a door handle in my office that hands out a fairly dramatic static jolt from time to time, but hasn't killed anyone yet.


This is a common problem easiest way to fix this problem is to wear high heel shoes with a pair of rubberised odour-eaters inside them :-)

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## Dave A

Sounds enticingly kinky, but I'm not sure my dodgy back could take the high heels...  :Stick Out Tongue:

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## Jacques#1

I've got a new one...Has anyone come across this before?

Overhead lines across the road, feeds down the pole and under the street to a house more than 100 years old (assuming).  The cable runs up the wall and in under a galvinised roof.  A makeshift connection is done at this point and a 10mm earth cable runs back down the cable to a spike about 50cm from the house.  Inside the house the db sits surface mounted with one entry hole only.  L+N cables comes through this hole and only 3 earth wires.  The ceiling is also steel.

Without having done any faultfinding yet, here's the problem...I'll go back there in the daylight to see whats happening.

The house constantly gets hit by lightning.  The lightning however fires blue flames out of all the socket outlets and the lightswitches, which are all steel.  You can see the evidence by looking at the black burned coverplates and walls surrounding the S/O's and switches.  Now, not having done a loop impedance and a spike test yet, i'm in 2 minds about this.  

When lightning hits your house it searches for the fastest possible route down to earth, it also hits your house because it is grounded.  It hits often because it is grounded, and everything is metal, but, the blackening of all the electrical equipment indicates that the lightning hits the house and rather than running down to earth (with some damage to equipment), it fires out at every end.  It would seem that there is no ground on the house, and the lightning actually follows the live conductor, hoping to piggyback to an earth?????  But then again, with no ground, why does it get hit so many times?????  There are plenty of other houses very close?

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## Dave A

Two things come to mind on the regular strikes - 

The roof of the house could be sitting at a different potential to the houses around it due to not being earthed back to the transformer, or

There's a sharp metal point somewhere on the roof which intensifies the electromagnetic field and could be atrracting the unwanted attention.

The sparks are probably because the earth is floating too far off the neutral during the strike. The loop impedance test should pick that up. You might get an interesting voltage reading between neutral and earth too.

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## AndyD

I like Dave's theory, sharp edges or acute angles etc might attract lightning. 

I'm not sure if I understand the layout you're working with here. There's an earth spike close to the house, does the earth wire from the spike go directly to the DB earth bar or is it bonded with the neutral where the supply wires enter the house? Is there a meter somewhere on the premises or is it an ED? 

The lack of earth wiring coming from the DB is not uncommon in old installations where the steel conduit was the earth and it was common practice to just bond all the conduits at the DB with straps and a single earth wire. I woul test the earth spike first and post the results if you feel like it. The neutral - earth bond resistance would also be nice to know as well as the neutral - earth voltage when there is a load on the system.

Is the roof steel sheet construction? If it is then maybe the roof is bonded to earth by physical contact with the steel conduiting. If it is then this might make it more attractive to lightning. If you can 'unearth' the roof so it's just at floating potential and perhaps you can install a separate earth spike far away from the electrical earth and install a lightning conductor.

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## Dave A

I suspect metal roofs are supposed to be bonded to earth i.t.o. the regulations - and for good reason.

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## Jacques#1

I've got some work to do on the premises, but will only go back once the builders do their thing.  The entire roof and ceiling is metal.  I do not believe the earth is joined with the neutral at all anywhere close to the premises at least, it looks like a TT system (can never tell as you don't know if council used the armouring as earth......which is allowed if the impedance is low enough.....but from a visual perspective....TT).  I went to council and they said that if I don;t come right, they'll come join the N+E at the pole.

The E to N voltage was the first thing I tested in the house, to make sure E is not Live all of a sudden, and touching a SO may be the last thing I touch.

What I did see, thought it was strange at the time, but pondering over it the last few days:  "the main cable runs up the wall and a 10mm earth runs back down to a spike about 50cm from the house".....wrapped around the earth was a small 2.5mm earth wire - bare - all the down and also joined.  What I think they did:  the council supply runs up the wall, where the armouring is earthed and runs back down.  From the DB a 2.5mm wire runs down the earth wire, and is connected to the spike.  "Potentially", if this is true, that thin 2.5mm earthing the entire house, and being so damn flimsy, could have broken off by the last guy that walked through the roof?

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## Jacques#1

This though...still leaves me with the question, if my hypothesis is correct....why all the strikes on a floating earth???

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## Jacques#1

Sory Andy, you were asking about the meter....it sits about 10 cm from the db on the wall, with a CB with open ends next to it (main), luckily they put is around 2.2m, so a normal person would not accidentally bump the exposed main feeder!!!!!!!! :Mad:

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