Bonding Cast Iron Pipe

[bureaucrazy]

Hello.
The toilet is connected into a cast iron waste/soil pipe O.D. 150mm.
Apparently, this is an extraneous conductive part and is thus supposed to have a main protective bonding conductor connected back to the MET.

There is a bonding clamp for 150mm O.D. pipes available.

However, the pipe will be painted to prevent further corrosion, so the contact with the clamp will be poor.
If paint is removed to contact the clamp, the pipe will corrode due to the high humidity of the location.

Would rather not drill or screw anything into the pipe.

What is the correct way to deal with this? If the pipe is painted so that it is not conductive enough to have continuity with a bonding clamp, perhaps it is not conductive enough to warrant bonding?

According to the regs, it seems this needs bonding. According to the EICR guide, missing main bonding is a code 2 fail.

Would any of you code a lack of bonding of a soil pipe on an EICR?

What is the standard way to deal with this and comply with the regs?

 

[Spoon]

Has the waste pipe actually been tested to see if it's an extraneous conductive part?

 

[Sintra]

Firstly I would test to see if it is actually extraneous rather than being told that it is.

RCP >U0–ZTL where: Rcp is the measured resistance between the conductive part concerned and the MET of the installation (in ohms), Uo is the nominal voltage to Earth of the installation (in volts), Ib is the value of current through the human body (or livestock) which should not be exceeded (in amperes), and Ztl is the impedance of the human body or livestock (in ohms). Guide to effects of current on human beings and livestock provides data for Ztl and Ib. For hand-to-hand contact, the value of the body impedance is given as 1000 Ohms in dry conditions where Uo is 230 V. You can then select a value of Ib between the two extremes: 0.5 mA – the threshold of perception and 10 mA – the let-go threshold Rcp>(Uo/Ib)–Ztl=(230/0.01)-1000=23000–1000=22Kohms

 

[pirate]

Angle grinder, scrape the paint off. big Jubilee clip, bond it, paint over...them find somewhere to connect your cable...and do a nice laminated label

 

[pirate]

Clearly out of my depth here...

 

[davesparks]

Assuming bonding is needed then clean the paint off, fit an earth strap like the ones used for lightning protection systems. These are made of a copper band which clamps around the pipe and can be easily painted over leaving a copper tag sticking out to connect the main bond onto.

Something like this Pipe Bonds - https://www.jointingtech.co.uk/Pipe-Bonds

 

[Megawatt]

Assuming bonding is needed then clean the paint off, fit an earth strap like the ones used for lightning protection systems. These are made of a copper band which clamps around the pipe and can be easily painted over leaving a copper tag sticking out to connect the main bond onto.

Something like this Pipe Bonds - https://www.jointingtech.co.uk/Pipe-Bonds

Does the pipe have flanges with bolts?

 

[Pete999]

Hello.
The toilet is connected into a cast iron waste/soil pipe O.D. 150mm.
Apparently, this is an extraneous conductive part and is thus supposed to have a main protective bonding conductor connected back to the MET.

There is a bonding clamp for 150mm O.D. pipes available.

However, the pipe will be painted to prevent further corrosion, so the contact with the clamp will be poor.
If paint is removed to contact the clamp, the pipe will corrode due to the high humidity of the location.

Would rather not drill or screw anything into the pipe.

What is the correct way to deal with this? If the pipe is painted so that it is not conductive enough to have continuity with a bonding clamp, perhaps it is not conductive enough to warrant bonding?

According to the regs, it seems this needs bonding. According to the EICR guide, missing main bonding is a code 2 fail.

Would any of you code a lack of bonding of a soil pipe on an EICR?

What is the standard way to deal with this and comply with the regs?

Apparently this is an "extraneous part", who says? has it been tested to see if it actually is an extraneous part?

 

[davesparks]

Apparently this is an "extraneous part", who says? has it been tested to see if it actually is an extraneous part?

Obviously it does need testing but my experience is that cast iron soil stacks that are exposed within the installation do test as extraneous and need bonding.

 

[davesparks]

Does the pipe have flanges with bolts?

Not usually, old fashioned cast iron soil stacks in the UK had a socket at one end of the pipe which the next pipe slots in to. The joint was then packed with some kind of rope and caulked with a cement.

 

[Pete999]

Not usually, old fashioned cast iron soil stacks in the UK had a socket at one end of the pipe which the next pipe slots in to. The joint was then packed with some kind of rope and caulked with a cement.

Soil stacks are usually installed in a Bathroom, within which the electrics should be protect by an RCD! which MAY negate the need for bonding extraneous conductive parts.

 

[davesparks]

Soil stacks are usually installed in a Bathroom, within which the electrics should be protect by an RCD! which MAY negate the need for bonding extraneous conductive parts.

An RCD doesn't negate the need for main bonding, it only affects supplementary bonding.
Soil stacks pass through other rooms too, and the times I've had to bond them has been when they are exposed inside other rooms such as a garage or other lean-to type construction on the side of a house.

 

[Pete999]

A cast iron Soil stack could be considered as an Extraneous Conductive part, in fact it would require both main equipotential and Supplementary within the Bathroom. Unfortunately BS7671 does not consider service pipework which is not accessible.

 

[PEG]

When considering bonding connections,i would confirm that it is cast,and not wrought,steel or other...and i have seen aluminium and copper,painted,which confuses further.

I would test first,of course,but in larger,older properties,the bit which would ensure it's connection with terra,is usually the part altered first,and may well be plastic.

 

[Timbo]

Weld a tag on the pipe to bolt to.