Shower near cu and main bonding

[Apache]

My take on it would still be to bond main gas and water. The 17th regs are still hazey on existing installations. You will find that although the main gas service will be poly pipe underground, it should be steel galv above ground.Gas should be bonded within 600mm of the meter. Have also come across situations were copper pipes through out the house have been joined by plastic push fit joints. This meant that all pipe work had to be bonded between every joint. That was a real pain.On the point of the c.u. being in the same room as the shower. This is a total bend on building regs. Sounds like the electrical cuboard has been altered to make room for an additional shower room. This should have been moved during the original conversion.

That surly isn't main bonding but supplemental bonding that has been done away with under the 17? Would look absolutely awful and what benefit would you get? The water itself conducts.

:|

 

[binky]

The water itself conducts.

:|

Water is actually a poor conductor of electricity - its the impurities that conduct it along, sea water especially. Any poly pipe over 1m long is such a high resistance as to be almost infinity (that's from memory - there is an article on the subject somewhere). As for pipe work with joins????? I think I would test the conductance over exposed lengths of metalwork in bathrooms and other special locations, back to to MET and make descision accordingly - anything over 8000ohms don't bond (based on 240v/30mA). The whole point is avoiding an earth path whilst at higher risk during fault conditions

 

[EL Zappo]

The example i gave on the push fit scenario was a few years ago. Supplementary bonding was essential at the time. Earth continuity tests between water pipes and the main earth were in excess of 400ohms .

I have come across situations in the past where the earth impedence has been so high that under fault conditions pipe work has become live and acted like an immersion heating water to a degree where it was spewing hot water out of the cold taps. Steel conduits in the walls heating up like radiators is also a sure sign of poor earthing. Early symptoms are your customers electric bill suddenly doubling.

 

[EL Zappo]

Sorry. deviating from the original questions.

Q1. Fit main bonds on both gas and water.

Q2. Install 17th edition board. This will help cover the whole house including the lighting for the shower room.