Is it still a Main Protective Bonding Conductor?

[shazbutz]

B. Gas decided to a. relocate a customers meter and b. connect it to the gas main in plastic. The old meter was removed leaving a stub of pipe with the MPBC still connected. My view is that this is now an earth rod, auxiliary to the distributor earthing conductor.. Another guy looked at it and said its still good for MPBC.
It's a PME supply with good Ze.
Settle a debate please....

 

[Pete999]

Some say, that if it can still introduce a potential into the property then it should be bonded. as extraneous

 

[shazbutz]

Apologies, more info. The stub is about 150mm and located in a to be boxed in area under the stairs. It's going to be impractical to confirm its continuity in future when the builder has finished

 

[Pete999]

I believe you have to make the call, is it extraneous metal work? others when they get home from work may have a differing opinion, sorry I can't be of more help, how difficult would it be to bond it?

 

[shazbutz]

Pete, it is already bonded. I guess the question is what do I call it. Supplementary or main?

 

[telectrix]

if it's extraneous, entering the building, then the bond to it is a main bonding conductor. end of.

 

[shazbutz]

Main bonding it is then.

 

[telectrix]

and 10mm if it's PME.

 

[Engineer54]

If it was extraneous before the meter was moved, then it's still going to be extraneous NOW!!

If the pipe has been totally isolated from any gas supply both inside and outside, it could well also act as a local earth rod (if it has a Ra value in single figures) that can be used to reinforce the DNO PME's supply. Either way it needs to be connected to the installations MET ...and as Tel stated, with a 10mm conductor

 

[telectrix]

but if isolated from incoming gas supply, and acting as an earth rod, then the cable to it would be an earthing conductor, not a bonding conductor.:rofl:

 

[Engineer54]

but if isolated from incoming gas supply, and acting as an earth rod, then the cable to it would be an earthing conductor, not a bonding conductor.:rofl:

Call it what you like, so long as it gets connected to the MET, it's a Good-un as they say...lol!!

 

[shazbutz]

and B Gas input following ages being passed around and on hold? " get your angle grinder and the pipe off at floor level, it's not connected to our network"

 

[GMES]

And if the pipe is painted then ask uksparks to come and sort it out for you he's a dab hand at them . :rofl:

 

[davesparks]

Test it to see what it's Ra is, if it's any good then leave it connected as an earth rod and include the info with your certificate.

 

[shazbutz]

Thanks Dave, that's what I wanted to hear.

 

[Knobhead]

I found the original redundant steel gas pipe that had fed my house. Didn’t take me long to weld a stud to it and connect it to the earth nest. I was on a TT supply back then.

Don’t ask me why. A steel gas pipe makes nearly always makes a better earth than the old lead water pipes.

At work I had 4 x 8” welded steel ducts laid under a double rail track and two heavy haulage roads about 200’ in length each. Each had a stud welded at each end. One end was connected to the substation MET the other end to the switch room transformer bays MET.
My philosophy is if it’s conductive and it’s in the ground, use it.

PS I’ve only worked on private MV networks so don’t start quoting BS7671.

 

[Engineer54]

Thanks Dave, that's what I wanted to hear.

I told you the same thing back at post 9!!!

 

[davesparks]

I told you the same thing back at post 9!!!

Yes you did, and I was just repeating your advice. But some people just need to be told the same thing a couple of dozen times before they actually listen.