Metal Bath Waste Pipes

[Bulmer]

Should lead waste pipes have a main equipotential bond back to the MET, even if they dont come into contact with the main cast iron soil stack outside, or just supplementry bonded along with the hot/cols/rads in the bathroom.

Cheers Guys

 

[ashrow]

my understanding of the regs
16th continual cross bond to hot, cold, light, shower etc
17th no cross bond required if install meets the regs ie RCD to circuits. main bonding correct size, test readings are below maximum in the BRB

Ash

 

[steamboatwilly]

BBC NEWS | England | Cornwall | 'Faults' caused tenant bath death

It's this kind of tragic situation which makes you think about the belt and braces of RCD protection AND bonding?

 

[Spudnik]

Testing between the pipe and earth will tell you whether it needs bonding, not the 17th edition.

 

[steamboatwilly]

Testing between the pipe and earth will tell you whether it needs bonding, not the 17th edition.

...and from the story above...

"He had measured 175 volts between the bath taps and a waste pipe in the bathroom..."

 

[Spudnik]

Indeed but an IR test should be carried out as i described.

There is a danger of introducing a potential if the pipe is isolated from earth and its bonded.

Just because its metal, doesnt mean it needs bonding.

 

[electricAl]

Indeed but an IR test should be carried out as i described.

There is a danger of introducing a potential if the pipe is isolated from earth and its bonded.

Just because its metal, doesnt mean it needs bonding.

e.g. if you have metal window frames they won`t need bonding - but they may need painting

As Jason said, an IR test between a metallic `object` & earth should be conducted - a reading 20-30k or above dictates the item should NOT be bonded (below 20k ohms then it should)

...as in: test voltage of 500v divided by non-lethal current of 25mA gives 20,000 ohms

...yet another instance of the use of Ohms law basically. Modify non-lethal current to manipulate max resistance reading as you see fit...

as in: 500v/20mA=25kohm