Bonding clips in the approved position

[Evans Electric]

It cropped up yet again this week ,  we'd left a bonding cable  by the incoming water , there were a load of copper pipes there , obviously to altered etc  .    So now all the pipework had been removed except for ...stop ****... then copper pipe with plastic fittings .   So what is the point of any bonding when there is no mechanical  continuity throughout the system . ?

I've raised this with various parts of our industry and have been told to  do as the regs state .  bond  just above the stop valve  , the rest is not my concern.     

In my opinion this is carp. 

In fact I've often fitted the water bond  to have the plumber chop the pipe and shove a plastic tee in the system  right above it . 

 

[ProDave]

I had one recently where there was a soldered copper tee almost touching the stopcock so I had to bond to one side of that tee. Of course we are supposed to bond before a branch, but as it's a soldered tee it makes no difference where it is bonded.

 

[Tony S]

Due to a total PC crash I can't give the mm2 for copper pipe. What I can say is the pipe is far superior as an electrical conductor 

 

[Sharpend]

If the copper is less than a metre with rest as plastic the bond is not needed. 

 

[Sidewinder]

If the incoming pipe is plastic, then no matter what comes after no main bond is needed.

 

[kerching]

Many years ago we did a conversion of one building into 6 workshop units

remote metering room

next to this was a Bulk gas meter....each unit had its own sub meter

incomer to meter 4" plastic

output from meter 4" plastic

nothing else in room...not even a light

took NIC man to it.....he insisted that we ran a BFO Earth wire to it as the meter was metal. I asked him what we should do with it when it got there. He didn't know...I proferred a suggestion which involved 'short jerky movements and travel'

 

[Andy™]

If the copper is less than a metre with rest as plastic the bond is not needed. 

nope, length has nothing to do with it. if the incoming pipe is not extraneous it doesnt need bonded. only useful thing from 18th draft so far is the requirement to bond or not is made clearer

 

[Evans Electric]

The job I'm referring to has a lead pipe incomer  ...then a load of copper pipe  for heating , cold & hot  etc  all with continuous  soldered joints  ,  its all in a utility room  and its  all extraneous  ...but  the plumber has fitted an insulated section ,  as in thousands of other premises &  the powers that be  make no comment .  

In this case I have moved the bond to the mass of copper at the boiler . 

 

[Andy™]

the mass of pipes at the boiler are not extraneous (and indirectly earthed through boilers CPC), the bit of lead pipe coming in is and its what should be bonded

 

[Blue Duck]

@Evans Electric

Did you bond the radiators also?

:innocent

 

[Evans Electric]

No radiators to be seen Ducky.

the mass of pipes at the boiler are not extraneous (and indirectly earthed through boilers CPC), the bit of lead pipe coming in is and its what should be bonded

Doesn't matter about all the pipes within the building then  ?    My incorrect reference, should have said Exposed Conductive Part.  

The gas on the other hand is a plastic incomer  with our bond just after the meter , so it's purpose must be to bond the internal copper work  to the same potential as the electrical earth.  Gas seems to use solid mechanical joints throughout  but it doesn't follow with  water .  

 

[Doc Hudson]

No radiators to be seen Ducky.

Doesn't matter about all the pipes within the building then  ?    My incorrect reference, should have said Exposed Conductive Part.  

My understanding would be as follows;    An exposed conductive part is described as a piece of equipment that can be touched that is not normally live but could become live during a fault conditions.  e.g. the metal outer casing of some switchgear, distribution apparatus, a load or accessory performing some function etc. But basically the exposed conductive part will typically have live parts inside of it.

Copper water pipes themselves are not exposed conductive parts by the definition of BS7671, as they don't have live internal parts, just water or gas etc.  (even though they could be both an exposed pipe and if a potential was applied they could conduct a current).  Whereas a metal cased central heating pump or a 2-port valve do both have exposed conductive parts, but they are both earthed by their integral earth wires.

Extraneous conductive parts are metal conductive parts with no internal live parts, but they are in contact with the general mass of earth so can introduce an earth potential and a direct path back to the supply transformer in the event of a fault.

If the pipes in the building cannot introduce an earth potential, and do not have live internal parts that could introduce a dangerous potential with respect to earth, then whatever they are made out of they cannot introduce any danger therefore do not need bonding.

Doc H. 

 

[Sharpend]

nope, length has nothing to do with it. if the incoming pipe is not extraneous it doesnt need bonded. only useful thing from 18th draft so far is the requirement to bond or not is made clearer

This is the interpretation of the regs according to the niccy people, although this may have changed as this was a few years ago that I was advised. 

Personally on new properties both the gas and water incomers are plastic so don't see the need to bond either. Obviously older properties it may be different as incomers were metallic. 

 

[Andy™]

Doesn't matter about all the pipes within the building then

nope. internal pipework is fairly irrelevant. its the imcoming pipes that are the problem. unless some copper pipes run under the foor and are in contact with earth, then they may be extraneous and require bonding.

if you have a TT supply coming in from a lead service cable, then that should be bonded too because its extraneous....

in older properties, if the soil stack is cast / lead coming into the property then you should be bonding that too.

 

[Evans Electric]

Have things changed then ?    What happened to  bonding water pipes  in case a fault causes them to become live  ?  

And to creating a "Gage"  within the building .  

I've had quite a few cases of live pipes & sink tops ..where the board was 3036  and the immersion heater had become two exposed  rods in the water cylinder ,  fuses tend not to blow in those cases .

 

[Lurch]

What happened to  bonding water pipes  in case a fault causes them to become live

When was that a thing?

Are we back to the old metal window frames and teaspoons thing? Not everything metal needs an earth, on my desk I have a stapler, a metal ruler, some metal pens.....

How would you expect the pipes to become live?

 

[Andy™]

thy never were bonded in case a fault made them live. they should never become live from something inside the property since everything should be DI or earthed. they are bonded so that they cant introduce a potential into the property, or if they do, then everything is at the same potential

 

[Evans Electric]

then everything is at the same potential

Thats what I'm saying ,   a gage is formed by strapping all the various  internal pipes together ...irrespective of whether they are metallic  in the ground.    Which would put them at earth potential anyway . 

The plumber inserting his plastic fitting after  the earth clip  would negate the connection to the water  pies  IMO 

 

[Andy™]

The plumber inserting his plastic fitting after  the earth clip  would negate the connection to the water  pies  IMO 

if there is a bit of plastic fitted, then the pipe now cannot become live due to external influences, so no problem

 

[Mark2spark]

This is the interpretation of the regs according to the niccy people, although this may have changed as this was a few years ago that I was advised. 

Personally on new properties both the gas and water incomers are plastic so don't see the need to bond either. Obviously older properties it may be different as incomers were metallic. 

Tell me, have you (everyone?) stopped bonding gas incoming copper pipes, because the service pipe is plastic?

We stopped bonding water pipes a good few years ago now, but still 10mm bond gas pipes because (I suppose) the copper pipe (consumer side of the gas meter) enters the building through the brick/blockwork, and is therefore in contact with the fabric of the building, i.e., earth.

I'm talking about new build, building sites.