Bonding of cast iron toilet waste??

[Underpaid]

Has anyone ever bonded a cast iron waste pipe? and if so what were the circumstances? Can u buy some kind of freaky long bonding clamp? As it states in the regs not to join two clamps together.

 

[Marvo]

Have you tested the pipe?

You get a perforated bonding strap that comes in long lengths.

 

[davesparks]

Yes I have, in the circumstances where it was an extraneous conductive part and I used earth clamps with a suitable length strap (obtained by asking for them at the wholesalers)
It doesn't state anything in the regs about joining two clamps together, but it does in the guidance notes.

 

[Marvo]

Hmmm, maybe scratch my idea then, it might not be suitable for the UK.

 

[davesparks]

Hmmm, maybe scratch my idea then, it might not be suitable for the UK.

Your idea should be fine, but there is an off the shelf bs951 earth clamp that will fit

 

[Marvo]

Thanks Dave, I'm always a bit wary about different UK requirements. We use the strapping quite regularly, it's handy for larger pipes plus and other components and you can use the strap as the wire so no need for joints.

 

[Knobhead]

I've used miles of that stuff over the years.

The only problem with bonding a cast iron pipe is the joints. You’d stuggle to get any continuity through them.

 

[Leesparkykent]

AEC 5/4 £9.45| AEC 5/6 £10.50 | Niglon Long Earth Clamp | Ntech Supplies Ltd

 

[LeeH]

I've used miles of that stuff over the years.

The only problem with bonding a cast iron pipe is the joints. You’d stuggle to get any continuity through them.

Begs the question is it really extraneous then.

 

[ian.settle1]

I've used miles of that stuff over the years.

The only problem with bonding a cast iron pipe is the joints. You’d stuggle to get any continuity through them.

Yep as cement is used to seal the joints

 

[Knobhead]

Traditional joints were tarred jute string and capped with putty. Cement cracks with any expansion/contraction.

 

[PEG]

Yep as cement is used to seal the joints

Hemp,and mortar,on older systems,as Tony said,continuity would be dubious.:icon12:

 

[Leesparkykent]

Why would you be worried about continuity on the sections of the cast iron waste if you have bonded the parts that have been proved as extraneous?

 

[Knobhead]

Hemp,and mortar,on older systems,as Tony said,continuity would be dubious.:icon12:

With modern ductile iron pipe would be even more dubious. Rubber seals are used.




One of the many weird things I’ve got involved with was pumping water continuously around four 8m sections of 1000mmID ductile iron pipe. I don’t know why but out of interest I checked for continuity across a joint. I can’t remember the reading but you certainly wouldn’t rely on them for any form of continuity.

As for why we were pumping water around in circles? If I was to say for the good of our health you’d think I was being sarcastic. Far from it, it was to find out the amount of solubles leached out of the cement lining. As I said, for the good of our health.

 

[Knobhead]

I’ve just looked in the 16[SUP]th[/SUP] OSG. Bonding a metal soil pipe in a bathroom was a requirement.

I’m going to make a wild guess being as the OP has cleared off, he’s found a bonded pipe doing an inspection and it’s not in his IET comic book.

 

[Deleted member 9648]

I've used miles of that stuff over the years.

The only problem with bonding a cast iron pipe is the joints. You’d stuggle to get any continuity through them.

Why would you want continuity through them?
If a cast iron soil pipe was extraneous then it would be bonded at the point of entry to the equipotential zone,it's purpose has then been fulfilled.
Your lack of understanding of main bonding never ceases to amaze me.

 

[7029 dave]

Well he's not an cable monkey like the rest of us. hee hee

 

[Silly Sausage]

I get a feeling the Mods maybe busy this evening! :smilielol5:

 

[Knobhead]

Your lack of understanding of main bonding never ceases to amaze me.

My lack of understanding of the IET’s requirement for bonding is simply because they fall miserably short of any standards I’ve worked to.

Now if you care to explain the physics and electrical principals behind your statement, I’ll listen to you.
Quoting the IET comic book cuts no ice with me. You have to use physics and electrical principals.

I’ll just add, BS7671 is a minimum standard.

 

[GB.Kayak]

Why would you want continuity through them?If a cast iron soil pipe was extraneous then it would be bonded at the point of entry to the equipotential zone,it's purpose has then been fulfilled.Your lack of understanding of main bonding never ceases to amaze me.

I am taking an educated guess here ... I am open to correction! If there is no continuity across the joints of a cast iron soil stack then it cannot introduce a potential into the 'equipotential zone' and therefore does not need bonding ... QED!

 

[Leesparkykent]

I am taking an educated guess here ... I am open to correction! If there is no continuity across the joints of a cast iron soil stack then it cannot introduce a potential into the 'equipotential zone' and therefore does not need bonding ... QED!

You may find the part of the cast iron stack that comes out of the ground maybe extraneous (obviously carry out a test to find this out). If the joints of the soil stack as it goes up the building don't allow continuity then obviously it's unlikely the rest of the stack is going to be extraneous.

 

[Deleted member 9648]

My lack of understanding of the IET’s requirement for bonding is simply because they fall miserably short of any standards I’ve worked to.

Now if you care to explain the physics and electrical principals behind your statement, I’ll listen to you.
Quoting the IET comic book cuts no ice with me. You have to use physics and electrical principals.

I’ll just add, BS7671 is a minimum standard.

OK.
The internal structure of a building that a person is likely to come into contact with is essentially electrically insulated from the general mass of earth.In the event of a fault to conductive parts within the building those conductive parts may be subject to a dangerous voltage relative to the general mass of earth until the protective device disconnects. A person within the building in contact with conductive parts during the fault will be subject to that dangerous voltage,but by being effectively insulated from the general mass of earth by the building will not be at risk of a serious shock.
An extraneous part is effectively introducing the general mass of earth into the insulated structure of the building,and hence the possibility of being in simultaneous contact with a dangerous voltage and the general mass of earth within the building during a fault.Once within the building metallic pipes are no longer likely to gain an external earth potential. Therefore as long as the bonding is at the point of entry to the building the hazard has been dealt with and the rest of the metallic service is no longer extraneous regardless of continuity.

 

[Knobhead]

I am taking an educated guess here ... I am open to correction! If there is no continuity across the joints of a cast iron soil stack then it cannot introduce a potential into the 'equipotential zone' and therefore does not need bonding ... QED!

You may find the part of the cast iron stack that comes out of the ground maybe extraneous (obviously carry out a test to find this out). If the joints of the soil stack as it goes up the building don't allow continuity then obviously it's unlikely the rest of the stack is going to be extraneous.

Good point, except the jointing methods used in CI soil pipes are electrically unstable. The resistance across a joint can vary with the weather or if you and the wife had a vindaloo the night before.
Regarding the foot of the pipe being buried. Maybe 18” will be buried before it joins salt glaze pipe. Salt glaze is used as an insulator for LV.

I’m not arguing whether the pipe should or should not be bonded, I simply stated that if you wanted to rely on a CI pipe you can’t due to the joints. If anyone wants to get in to an argument over CI pipes, I worked on them for 12 years 5 in R&D. That’s how I happened to carry out the test across a socket and spigot joint.

I also said I think our OP had found a bonded pipe and as it’s not in the latest thrilling episode of the OSG he didn’t understand why it was done.

Just to make a point my first house I wired to the 14[SUP]th[/SUP]. I didn’t bond the soil pipe, the metal window frames or the knives and forks.

 

[GB.Kayak]

OK.
The internal structure of a building that a person is likely to come into contact with is essentially electrically insulated from the general mass of earth.In the event of a fault to conductive parts within the building those conductive parts may be subject to a dangerous voltage relative to the general mass of earth until the protective device disconnects. A person within the building in contact with conductive parts during the fault will be subject to that dangerous voltage,but by being effectively insulated from the general mass of earth by the building will not be at risk of a serious shock.
An extraneous part is effectively introducing the general mass of earth into the insulated structure of the building,and hence the possibility of being in simultaneous contact with a dangerous voltage and the general mass of earth within the building during a fault.Once within the building metallic pipes are no longer likely to gain an external earth potential. Therefore as long as the bonding is at the point of entry to the building the hazard has been dealt with and the rest of the metallic service is no longer extraneous regardless of continuity.

... but if there is no continuity between t'pipe in t'ground and t'pipe entering t'house then the cast iron is not an extraneous part!

 

[Underpaid]

First i isolated the installation, then using an insulation resistance tester, connect one lead to the main earth terminal and the other lead to the soil pipe, tested at 500v and my reading was much less than 23,000 ohms meaning that the soil pipe is considered an extraneous conductive part and needs main bonding