Equipotential Bonding dilemma

[crane]

I have been reading alot of information provided and believe my circumstance is a bit unusual....heres hoping someone can help??

I have an ex pub which has an unusual layout, we have a water main that enters the house underneath the concrete floor and pops up anywhere that it is needed......we have no internal stopcocks so its out to the street to turn off the water supply.

So heres the question,

Do I have to have send a 10mm cable to each point it pops out the concrete .....if so in 1 conected run or will mulitple runs from the CU be ok?

and the dilemma,

The pipe pops out the ground in the downstairs shower room, assuming it will require a 10mm cable connecting it to the CU and then will require supplementery bonding. According to the 17th edition you must not connect the supplementry bonding back to the CU .........surely thats exactly what you are doing as its a small shower room and all "exposed" pipes are right next to the point the cold feed leaves the concrete and so will be connected together??

Thanks in advance

Any advice appreciated!

 

[ricicle]

Does this pipe also leave the shower room. I would be inclined to supplementary bond it inside with all electrical cpcs and extraneous metalwork.
That way all metalwork's potetial inside the shower room would rise together in the event of a fault. I would then provide a main equipotential bond outside where it leaves the shower room.

 

[crane]

Thats is part of the problem,
there is no "outside" anywhere in the house. The pipes rise in each room that requires water.

As far as I can trace no main bonding is in place which will need sorting out. There are a few 2.5mm wires connecting some of the rooms together and then onto the CU....not really a solution and certainly not safe IMHO !


Is an answer to dig up outside and place a main earth bond where the mains water enters the concrete?

Would this be within regs?

 

[ricicle]

I meant outside the shower room but inside the house if the pipe left to go to another room but by the sounds of it, it doesnt.
I would treat the shower room as it's own equipotential zone and just supplementary bond to the circuit cpcs and extraneous metalwork if this cold pipe does not go anywhere else.

 

[crane]

Just been and checked the water pipes again and the cold feed does leave the shower room ,it goes through the wall to another bathroom....doh

definitely stops there, makes it even worse?

Do both bathrooms need supplementery bonding together?

Can this be main bonded somewhere between the 2?

 

[ricicle]

No the bathroom and shower room should be kept as independant equipotential zones. I personally would still omit the MEB

 

[RF Lighting]

Could you use a low ohms meter and test the pipework is effectively connected together at each point and if so, just bond at one point, and then supplementary bond as required.

 

[SgtTrojan]

Agreed ^^
1. Main protective bonding (single 10mm²) to the point of entry where the suppliers and consumers' installations meet. As there is no stop cock make the connection 600mm from the floor. This will ensure any changes made by the Water Authority will not affect your equipotential zone.
2. Using a low resistance ohm-meter conduct a Method 2 earth continuity test (wandering lead) to the newly earthed point (value to be less than 0.05 Ω ).
3. Continue this test to each point of pipe entry in each room. Assuming it's all metal pipework they will, in the eyes of BS7671, all be bonded from the one connection. Theoretically the value should not exceed 1667 Ω but start worrying if the value is anywhere near that!