Bonding

[Mattrod]

Hello sparks.

I have a job at the mo, on which i need a bit of advice on.

The property has a gas oven fed from a gas bottle, which is sited outside. It feeds straight through the kitchen wall into the cooker. I can't get to the pipe work behind the cooker, but will it still need a bond, say on the outside before it goes into the wall?

Also the centre heating is an oil fired. This is fed straight through the wall, again. I think I can just about get to the pipe work behind the boiler and bond there. Then do I just have to cross-bond the pipe work on the heating side?

Any advice received with thanks.

 

[Deleted member 26818]

Is the gas bottle not connected with a rubber hose?
Does the solid part of the pipework come into contact with the ground at all?
You can cross bond the heating pipework, but it probably isn't necessary as it's most likely connected via a metal manifold.

 

[Rockingit]

It has always been my understanding that gas and oil supplies should be bonded as per the BGB, it doesn't matter where they come from.

Others may have an alternative view, though.

 

[Deleted member 26818]

Only need bonding, if they introduce a PD.
No point for instance in bonding services, if they're plastic.

 

[technospark]

I agree with spinlondon. No chance of introduction of PD especially if the bottle is connected in rubber.

 

[Rockingit]

OK then, so what happens when the connecting pipe is copper, gas hob with electric ignition? I don't think the OP is talking about the actual bottles, just the pipework.

 

[Deleted member 26818]

OK then, so what happens when the connecting pipe is copper, gas hob with electric ignition? I don't think the OP is talking about the actual bottles, just the pipework.

That is why I asked if the solid part of the pipework came into contact with the ground.

 

[Mattrod]

That is why I asked if the solid part of the pipework came into contact with the ground.

I'm not sure if it is in contact. I go there next week to do the job. Have to check out the state of the pipework then. I hope it is in rubber then I can forget about it. I have to bond the oil, I know. Think I will cross bond the pipework, just in case. Can't be to careful. I am putting in a new 17th board so with the RCD's, there will be alot of protection.

On another ongoing job, I have a lighting circuit with no earths. I have to sup bond the bathroom but not sure on where I can take this back to. I thought the bond had to go back to a earth situ'ed within the bathroom zone, due to PD. Or can I either run in back to the MET or pick up a earth outside the zone?

Sometimes this job is a minefield on the head!

Keeps me thinking though!!

Thanks for the replies, guys. Always good to knock heads together.

 

[Deleted member 26818]

No you can take the bonds back to a point in close proximity to the location, then run a single conductor from that point back to the CU/MET.

 

[technospark]

No you can take the bonds back to a point in close proximity to the location, then run a single conductor from that point back to the CU/MET.

No need for this at all if the installation is fully protected by RCDs as per 17th edition. If not then you only need to create a 'Farady Cage' within the bathroom itself. i.e. bonding all the items specified ink the Regs within the bathroom or in the viscinity of it. You do not need to connect this supplementary bonding back to the origin.

 

[Engineer54]

No need for this at all if the installation is fully protected by RCDs as per 17th edition. If not then you only need to create a 'Farady Cage' within the bathroom itself. i.e. bonding all the items specified ink the Regs within the bathroom or in the viscinity of it. You do not need to connect this supplementary bonding back to the origin.

Really?? How does supplementary bonding a few water pipes etc, produce a ''Faraday cage''??

 

[technospark]

A Faraday cage is an area where all the metalwork is of the same potential i.e. 'equipotential' This potential may be true earth zero volts but in many cases, particularly some industrial environments it will not be.
Hence the need to bond everything within the bathroom (in Scientific terms the Faraday Cage ) so that one piece of earthed metalwork is not at a different potential from another piece of earthed metalwork.

I have measured considerable voltage differences between supposed earthed metalwork over my testing & inspection career.

 

[DPG]

I wouldn't say that bonding some metal items together creates a Faraday cage. A Faraday Cage is not the same as an equipotential zone. Daz

 

[technospark]

I would have agreed with you Daz before I did the inspection & testing course at York College!

 

[DPG]

A Faraday cage is intended to keep out electromagnetic interference. An equipotential zone is intended to minimise the chances of electric shock by keeping all exposed metalwork at the same potential. The 2 terms are not directly interchangable. Daz