Main Gas & Water Bonding

[Colin Integrale]

Evening folks,

I've got a bit of a problem,

My boss has just told me today that the main gas and water bonding CSA has to be upped on this job I'm on and it's damn near completion...

Originally 10mm was thrown in but was wrong so it was upped to 16mm.

Today I'm told it has to be 25mm.

Basically, the original 10mm and 16mm cables still remain in place to both services and I was wondering (I know it's not ideal) if I could use the combination of the two.

Both the cables are the same length on exactly the same route for each of the services.

I'm looking in the BRB at 543.2.2 ;

A protective conductor may consist of one or more of the following :

(i) A single core cable
(ii) A conductor in a cable

etc etc

I can put in new 25mm's if I have to, but it means ruining some finished ceilings and wasting time whilst I'm busy trying to finish up everything else

Any help here would be wicked.

Cheers

Colin

 

[morph]

its your boss problem then , he should of told you before . if he pays you then just rip out the old and put in new 25 mm

 

[Colin Integrale]

I'm just trying to avoid spoiling finished parts of a new build that needs practical completion in a week-and-a-half... And trying to save time for me to concentrate on the things that I need to nail.

Like I say, if I have to put new cables in, then so be it, but if it's not against regs to use the 16mm and 10mm combined then that's what I'd do. (not ideal as I said before, but **** happens)

 

[IQ Electrical]

Parallel cpc's are acceptable but not at different CSA's without careful consideration of current split so I think you're snookered!

I suppose your boss tried the adiabatic if the earthing system allowed?

Edit.

The regulations I was thinking of (433.4.2 and 523.8) seem to refer to live conductors.
I'm off out for a short while but maybe someone can check this?

Whatever the outcome is, I'd be going down the single, correctly sized MPBC route.

 

[DurhamSparky]

crimp 25mm to the ends of your 10 , poke a bit 25mm excess in cavity boss no wiser!! simples!!


all the rage on polish installs apparently!!

 

[Colin Integrale]

I've been to Poland, does that count?

 

[telectrix]

soon i think we will be getting food parcels from poland. i can't say too much as my lady's parents are polish- came here after the war.

 

[Colin Integrale]

Guess its a new 25mm then?

 

[Dunc]

What has made your boss come to the conclusion that 16mm is not adequate? What's the supply characteristics and distance from MET to gas/water?

 

[Colin Integrale]

PME 200A 3 Phase supply.

 

[Geordie Spark]

crimp 25mm to the ends of your 10 , poke a bit 25mm excess in cavity boss no wiser!! simples!!


all the rage on polish installs apparently!!

The last time I saw that it was 10mm chockblocked onto each end of 6mm.

I've also seen 22mm gas pipe running from a boiler to under the floor where it was connected to 15mm pipe. The boiler really needed the 22mm pipe to run all the way back to the meter to give it the correct rate of gas & wouldn't work properly.

 

[DurhamSparky]

lol....!

 

[telectrix]

simple solution. get your 25mm ready. then get 2 pikeys. tell em they can have the 10mm if they can pull the 25mm through with it as a draw wire.

 

[IQ Electrical]

PME 200A 3 Phase supply.

If he's gone from a 10mm to a 16mm to a 25mm it makes me wonder if he realises the requirements for PME protective bonding?

If the suppliers neutral (not the 'tails') is 50mm CSA or less then the 16mm will suffice.

This is assuming that there are no particular DNO special requirements.

 

[SimpleSimon]

Agree with IQ. 25mm seems overkill if the neutral is under 50mm. What's the building purpose? Has your boss gave a valid reason? I think I'm being dense but what do you mean by 200a?