Calor Gas Bonding on a static caravan

[jc-electrical]

Hi Folks,

This is my first post so thanks for your patience,

I have just started testing caravans (static caravans on permanent pitches that are not intended to be moved) and have come across calor gas supplies on a few of them. My question is, do these services need to be bonded? They are just gas bottles, sat on a concrete base with a copper pipe running beneath the caravan and up to the boiler.

Maybe a silly question bit it seems that alot of people have alot of different opinions on this subject.

Any thoughts are much appreciated.

 

[snowhead]

The rule is no different for LPG, bond internally within 600mm, where practical, of entry of service.

 

[jc-electrical]

Thanks for the fast reply. Is this because the pipework is an extraneous part? I had thought that because the pipework is not in contact with the ground, it would not introduce any potential into the caravan? Normally I would err on the side of caution and bond anyway but in this case the site has previous certs from a reputable company and they have not flagged this up so I am treading carefully. Thanks again.

 

[Engineer54]

The rule is no different for LPG, bond internally within 600mm, where practical, of entry of service.

Explain how this copper pipe off the top of a gas bottle is going to introduce an extraneous earth potential?? If we were talking about a bulk storage system, things would be very different, but a gas bottle sat on a concrete plinth will introduce none!!

 

[tony mc]

Have you tested the pipe coming in to see if it needs to be bonded ?

 

[jc-electrical]

I'm not sure I understand what you mean by 'test the pipe'. Could you please clarify?

 

[telectrix]

IR test from pipe to MET. if reading is >22kohms, then don't bond it.

 

[jc-electrical]

I have not carried out this test but I have taken continuity readings between the gas pipe at the boiler and the cpc from the lighting circuit (nearest known connection to earth) with no readings being higher than 0.30ohms.

To give a little more info on the installation,
-CCU is a 5way with a 30ma rcd main switch
-Supple is TNS (as far as I can tell - there is no access to the supply equipment, just the meter and connection to the caravan, in a waterproof enclosure, which is a 6mm2 TnE with the earths connected together)
-Water is bonded back to MET in 6mm2
-Gas service comes directly form calor bottles into the bolier - the only gas appliance

There is also a 16mm2 earth that is connected to the chassis and directly onto an earth rod

 

[telectrix]

probably find that the gas pipe is bonded to the water via the metalwork of the boiler.

 

[jc-electrical]

Yes that was my thoughts aswell. Although it still doesn't help me with regards to the gas requiring its own main bond connection or not. As always I am tempted to say it does and be done with it, and if it was my own installation I most likely would bond it without hesitation. However as this is a condition report and has previously gained a satisfactory result in the past (3 years ago) I really want to make sure I am getting this right before I issue the cert.

 

[ifindoubtdont]

On statics you will usually find a pair of gas bottles, these will be connected via rubber pig tails to an automatic change over valve. It will be all copper pipe work from there on. Gas connection at boiler is usually compression fitting. All gas pipe work will be copper all the way to hob/oven/grill. Water pipe work on more modern caravans will be plastic even the intake (to stop pipe splits in winter if you don't drain down properly). It is unlikely you will find any metallic connection between the caravan and ground other than the cpc or ground anchors.

 

[jc-electrical]

Ok thanks, so would I be right in thinking that as the pipework is not going to introduce any potential then there is no requirement for a dedicated main bond to this service?

 

[Geoffsd]

You cannot get yes or no answers on a forum.

If it is an extraneous-conductive-part then it must be (main) bonded. Is it?

 

[jc-electrical]

Thanks Geoff, I appreciate that and I am just hoping to tap into the wealth of knowledge on this forum and thought maybe there might be people here that have more experience with working on these installations than I do. As I said I cannot see how it could introduce an earth potential into the installation (no part of the pipework is buried or in contact with the ground) so therefore I would say that it cannot be called an extraneous conductive part. That is not to say that I am right, and any opinion is valuable to me, hence the post

 

[Geoffsd]

As I said I cannot see how it could introduce an earth potential into the installation (no part of the pipework is buried or in contact with the ground) so therefore I would say that it cannot be called an extraneous conductive part.

There you go, then.