more bonding questions.........sorry!!

[ashm]

hello and thanks to all that answer,
Could somebody please talk me through bonding requirements for a bathroom. At the moment all the copper pipes are bonded from the earth point at the CU with 4mm cable at the combi boiler ,situated across the landing (approx 1.5 metres). The lighting and shower circuit are protected by by an RCD on a split load CU.

Am i still required to bond each copper pipe in the bathroom to each circuit entering it?

 

[davy_owen_88]

At the moment all the copper pipes are bonded from the earth point at the CU with 4mm cable at the combi boiler

The main bonding back to the CU should be run in 10mm^2 cable and take effect within 600mm of the meter/stopcock.

Supplementary bonding does NOT go back to the CU. Either you have undersized main bonding conductors or have incorrectly installed supplementary bonding. Supp. bonding isn't a requirement anywhere apart from in bathrooms but some plumbers still cross-bond all pipes around the boiler.

The lighting and shower circuit are protected by by an RCD on a split load CU.

Am i still required to bond each copper pipe in the bathroom to each circuit entering it?

Yes.

Davy

 

[Spark123]

At present it is a requirement to eq. bond at the bathroom. This is to keep all metallic items that can introduce a potential at or very close to the same potential inside the bathroom in the event of a fault (inside or outside the bathroom). This bonding does not need to connect to the main earthing terminal (MET).
Any water pipes, gas pipes etcneed to be main bonded to the MET where they enter the building, see main equipotential bonding in the Wiki

 

[ashm]

okay... thanks for the replies...... bit confused!!! could you confirm the following

water/gas pipes entering the house need to be bonded from the CU with 10mm^2 within 600mm of the stop cock

each pipe in the bathroom needs bonding to a circuit

bonding at the boiler not required

thanks

 

[davy_owen_88]

That is correct. Cross bonding around the boiler is not a bad thing, it just isn't required. It should not be connected back to the CU either but again it isn't going to make it unsafe or anything.

Davy

 

[Spark123]

Cross bonding the boiler is not required by the IEE regs, it may however be a gas reg. What does the boiler installation instruction book say? The size of your main equipotential bonds (gas, water etc to MET) changes with varying supply types hence I said look in the wiki //wiki.diynot.com/electrics:main_equipotential_bonding.
There is also a section on supplementary bonding in a bathroom: //wiki.diynot.com/electrics:sp...l_bonding:supplementary_equipotential_bonding

 

[ashm]

that clears things up,

at the moment the only bonding is a 4mm^2 6 metre long cable run from the MET to the boiler and then cross bonded to the other pipes!!

 

[ashm]

great advice and links.

i will bond both the gas and water within 600mm of the stop cocks.

the boiler is cross bonded will check cable size etc

how do i bond the pipes in the bathroom to the circuits, there are hot/cold and radiator pipes and lighting and shower circuits, each pipe and circuit
only needs bonding once so i need bond 2 pipes to each circuit?

do i run the cables in the wall and exit using a special plate?

what size cable should i use?

 

[davy_owen_88]

Buy suitable clamps for the pipes you have to bond. Use 4mm^2 cable.

CPC's can be used as bonding conductors so you only need to bond the shower circuit at the shower or at the shower switch, same applies with the lights.

E.g you could bond the hot and cold water pipes together, then bond the cold to the earth terminal at the shower and then connect the earth terminal at the pull switch for the shower to the CPC of the light fitting.

Davy

 

[ricicle]

. Use 4mm^2 cable.

Davy

If you need to do mm² just type mm and hold down Alt key and type 0178 and release Alt.

(some kind soul showed me this a while back)

 

[ashm]

If you need to do mm² just type mm and hold down Alt key and type 0178 and release Alt.

didn't work for me???

 

[ashm]

okay excellent advice,thank you all very much, finally if i want to make a neat job and bury the bonding cables how do you 'exit' the wall. do you use a flex entry type plate or do you just plaster around the cable?

 

[bernardgreen]

If you need to do mm² just type mm and hold down Alt key and type 0178 and release Alt.

didn't work for me???

You have to use the numeric keys on the right hand side of the keyboard for this. (NUM LOCK on) The ones above the letters do not work...