[Article] New earth bonding test

[Alfred M]

https://ecasa.co.za/technical/sans-10142-1-and-the-bonding-test/

[Dylboy]

I have seen this and I dont agree with testing socket to exposed metal as a socket is earthed not bonded....

However I say this but I am undecided on what to really think, spoke to one guy when doing the unit standards and he says its wrong too.

But what does everyone else think ?
I will try read it better later this weekend and see if I agree with it or not

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[Dave A]

Doesn't this introduce a risk that we may fail to detect that accessible conductive parts may not be connected to the earth terminal?

[Dylboy]

That test is confirmed with the Resistance of earth continuity conductor.

But that test is technically the conductor but we often test the metal class 1 stuff with it too. And the reading as to be of table 8.1.

So earthed is items that carry electricity.
Bonding is items that don't carry electricity.

Fine line stuff this but the article makes sense to have it all at same potential and to verify that.

I like the test but perhaps a voltage check and not 0.2ohm bonding check as voltage proves bonded per say and same potential.

What you all think ?

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[Derlyn]

Does a geyser have an earthing terminal or is it a bonding terminal ?

[Dylboy]

Geyser is earthing terminal but we bond the hot and cold pipes.

So generally people bring 2.5mm earth cable to earth the geyser but then they take a lead off to hot and cold taps to bond so not to run extra bonding only cable.

That is how I see it and the train of thought.

In the UK they run separate bodming cables and say one is water, other is gas etc...

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[Derlyn]

Geyser is earthing terminal but we bond the hot and cold pipes.

So generally people bring 2.5mm earth cable to earth the geyser but then they take a lead off to hot and cold taps to bond so not to run extra bonding only cable.

That is how I see it and the train of thought.

In the UK they run separate bodming cables and say one is water, other is gas etc...

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The bonding conductor needs to be minimum 2,5mm, however the earth continuity conductor need not be.
The size of the earth continuity conductor will depend on the cable used to supply the appliance.

So if a geyser is wired with 1,5mm FTE then the ECC will be less than 1,5mm sq.
Now you bond the hot & cold pipes with 2,5mm and bond to the earthing terminal on geyser with 2,5mm.
The ECC is also connected to same earthing terminal on the geyser.

The bonding conductor is now 2,5mm and the ECC is less than 1,5mm.

Acceptable ?

I'm reading 6.13.2.2 and the above situation ticks the boxes.
I suppose one would first have to define "earth continuity conductor system"

What sayeth the other toppies ?

[Alfred M]

ECC or Earth Continuity Conductor is the part of the earthing or grounding system which joins or bonds together all the metallic parts of an installation network: Conduit, ducts, boxes, metal casing of switches, switch-fuses, distribution boards, regulating and controlling apparatus, exposed metal work of machines and any metal framework on which electrical apparatus are mounted.

[Derlyn]

I am aware of the difference between an earth continuity conductor and a bonding conductor.

The regulations state that the bonding conductor must be connected to the earth continuity conductor SYSTEM.

I am, however, not 100% sure of where, physically, this connection should be done.

Can it be made to any earth continuity conductor or must it be made directly to the consumer's earthing terminal. Hence my question regarding the definition of the earth continuity conductor SYSTEM.

[Dylboy]

Ahhh I see what you are saying ! Intresting observation.

I think somewhere it states about earth terminal connections... Will try look later

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[Alfred M]

I think what they are actually trying to achieve is if 2 conductive exposed objects are above 0.2ohms(specified tester) within arms reach they needed to be bonded together to the earth conductor back to the db creating more parallel paths on the installation earthing SYSTEM creating overall less chance for touch voltage on any given metal exposed object within arms reach

[Dylboy]

@Derlyn I found the below which I copied and states should be on E terminal in DB board

6.11.2 In every installation where main equipotential bonding is used, the
following shall be connected to the main earthing terminal in the distribution
board:
a) main equipotential bonding in accordance with 6.13;
b) earthing conductors;
c) bonding conductors, except for supplementary equipotential bonding
conductors for medical locations in accordance with 7.7.

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[Dylboy]

Morning Oom

I agree ! Never seen a dedicated bonding cable... I feel its always the cable feeding geyser that some is just what is used and luckily we get 0.2ohm on testing haha.

Once more in the UK they have dedicated 10mm˛ conductors or I think 6mm˛ depending distance and its labled and all.

Look when even I do a new build or renovation I will be running separate conductors and lable etc. Just neater and then I know its good

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[Derlyn]

@ Dylboy

I must have pressed the wrong button on my cellphone and my previous post has gone awol ...

It seems as if we have been doing it wrong all these years as I have never seen a bonding conductor from the geyser and water pipes going directly to the DB.
I have always bonded the water pipes in the attic to the ECC going to the geyser, as I'm sure many other guys do.

Now onto something else regarding earthing terminals ........ there are 4 types of which I am aware. Gonna name them in order from the supplier to the appliance.

1. Supplier earthing terminal.
2. Main earthing terminal.
3. Consumer earthing terminal.
4. Appliance earthing terminal.

Now picture a domestic installation.

1. The supplier earthing terminal is at the Supply authorities transformer.
2. The main earthing terminal is outside, on the pavement, in the stubby box.
3. The consumer earthing terminal / terminals are in the main DB and Sub DB's if there are any Sub DB's on the installation.
4. The appliance earthing terminal is on the appliance itself.

All too often, when it comes to earthing and bonding, I feel the incorrect terminology is used in SANS 10142 to describe the earthing terminal in question.
ie. 6.11.2 talks about the main earthing terminal in the distribution board. As far as I'm concerned, that's the consumers earthing terminal. The main one is on the pavement in the stubby.

Check out 6.13.2.6 refers to a distribution board earthing terminal and refers to 6.11.5 that calls it, quite correctly, the consumer's earthing terminal.

Why can't they just stick to one name for one thing ?
All very confusing.

Rant over.
Time to head to the distillery.

[Dylboy]

Hahaha sorry about that! I sometimes type a whole message, then phone down to help the small one do something and then its gone hahaha.

But with the geyser and the bonding, if you ran it in 2.5mm˛ at least its min size for bonding so good. In that case the geyser earth cable is also binding cable.

I did the unit standards course this week and the guy says thats how its been done and ok so then feel ok if the geyser earth wire 2.5mm˛. He says it saves running another conductor to then bond.

And yes agreed !!! I have drawn out that earth terminal thing from supplier and it confuses me with other things in the book. Now in UK the MET is on the box where the supplier stuff is haha.

Also off to the bar fridge a bit later, got a stew on the go and mates coming over... Happy Easter Sunday haha.

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