main bonding to external boiler.

[sparkygg]

This is my first post and hoping someone can help?

Just wired an external combi oil boiler. I ran a 10mm bond from CU to the incoming pipes which are all 22mm and 28mm copper. They come through the wall from outside and I have put an earth bonding clamp on each pipe and looped the bond between them all. Now I am not sure if I should have run the bond out to the oil line entering the boiler? It comes through the ground for 20m or so and pops up just beside the boiler which is mounted on a paving slab plinth. The oil pipe doesn't enter the building and as i said any metal pipes which do are now bonded. The incoming water is in blue polypipe and is bonded where it turns to copper further into the installation. What should I have bonded? I am confused!

Any guidance would be appreciated.

 

[SirKit Breaker]

Sounds OK to me, working on the theory that we bond gas on the consumers side of the meter, so you have bonded the pipes on your set up on the consumer side of the installation. I did something similar with gas tanks recently.

Cheers.........Howard

 

[scott1]

I have the same problem, dont recon it needs bonding. elecsa coming to inspect that job on tuesday, will let you know.

 

[sparkygg]

Just to let you know I had my Elecsa inspection on Wednesday and this job was one that Paul chose to view. Showed him that I had "cross bonded" all metal work entering the house all looped off the main bond to the incoming water with out any breaks. He said this was fine and if I had bonded outside to the oil I would have actually been extending the equipotential zone which would have worsened the situation. So I guess if you have done what I did you will be ok, but still a bit of a grey area in my view.

Thanks for the response its always good to know when think you may have done right but not 100% sure.

 

[scott1]

i had my inspection with elecsa today. he said he would like to see a bond on the external oil pipe connecetd to the external boiler, gray area with them to.

 

[SimpleSimon]

i had my inspection with elecsa today. he said he would like to see a bond on the external oil pipe connecetd to the external boiler, gray area with them to.

IMO this should be bonded if the incoming pipe to the oil boiler is copper as this would introduce and earth potential into the house. It does say on the certificate bonding-other services.

 

[scott1]

all pipes are bonded entering building, flow, return, hw and cold mains.

 

[SimpleSimon]

Is it or is it not bonded Scott? I'm confused? Or is the piping GOING outside?

 

[MarkieSparkie]

There is no requirement to bond the oil pipe to an external oil fired boiler as it cannot introduce a potential into the property. As long as the water supply pipe to the property is bonded to the MET and if there is <0.05 ohms continuity between the MET and the heating service pipes at the boiler (as is usually the case due an all metal manifold) then there is no need to supplementary bond these either.

 

[SimpleSimon]

There is no requirement to bond the oil pipe to an external oil fired boiler as it cannot introduce a potential into the property. As long as the water supply pipe to the property is bonded to the MET and if there is <0.05 ohms continuity between the MET and the heating service pipes at the boiler (as is usually the case due an all metal manifold) then there is no need to supplementary bond these either.

Didn't think there was a supply water pipe to the boiler! How silly. Yeah Markie's right.

 

[sparkygg]

Basically as long as all pipes entering the property are bonded this is ok. I even rang the Niceic tech support line that my mate belongs to, and they say not to bond the oil if its external and never enters the building.

Be nice if the Elecsa inspectors could agree though!

thanks for all your replies.

Sparky GG

 

[Nightmare1308]

I agree really that u shouldn't bond the oil if it never enters The building as it would be at a different potential to outside the idea of bonds i thought was to bring everything extraneous to The same potential in case of a fault or a difference in potential ? I would like to here a electrical council advice as they cover us ?

 

[Engineer54]

Just to let you know I had my Elecsa inspection on Wednesday and this job was one that Paul chose to view. Showed him that I had "cross bonded" all metal work entering the house all looped off the main bond to the incoming water with out any breaks. He said this was fine and if I had bonded outside to the oil I would have actually been extending the equipotential zone which would have worsened the situation. So I guess if you have done what I did you will be ok, but still a bit of a grey area in my view.

Thanks for the response its always good to know when think you may have done right but not 100% sure.

Why would extending the equipotential zone worsened the situation?? I take it you have an electrical supply to this boiler which is being supplied with oil from an underground metallic pipe ...Right?? So the equipotential zone ''Needed'' to be extended didn't it!!!

What is the oil tank construction, ...metal or non-metallic?? How is the oil tank filled, ...via a filling pipe extending to the property boundary, or via a filling attachment close to the tank?? If these are metallic, then they need to also be ''Earthed'', as the filling tanker will need a connection point for his oil tankers equalisation extension lead.

 

[Deleted member 9648]

Why would extending the equipotential zone worsened the situation?? I take it you have an electrical supply to this boiler which is being supplied with oil from an underground metallic pipe ...Right?? So the equipotential zone ''Needed'' to be extended didn't it!!!

What is the oil tank construction, ...metal or non-metallic?? How is the oil tank filled, ...via a filling pipe extending to the property boundary, or via a filling attachment close to the tank?? If these are metallic, then they need to also be ''Earthed'', as the filling tanker will need a connection point for his oil tankers equalisation extension lead.

I'll take issue with this.
It is not possible to have an 'equipotential zone ' in an external situation...(such as surrounding an external boiler).....in such a situation the boiler is surrounded by the general mass of earth so it would be pointless trying to create an equipotential zone by bonding the oil line.
The equipotential zone is in the building , and the heating pipes coming from the boiler introduce an earth potential...(possibly from the oil line)....therefore it is correct to main bond the heating points at the point of entry.

 

[Deleted member 26818]

To my mind, if the oil pipe is considered an extraneous-conductive-part, it will require bonding.
If the boiler is within the building, the oil pipe will require bonding as close as practicable to where it enters the building, preferably within 600mm.
If the boiler is in another building, then it may be that it should be treated as a separate installation, and will require it's own earthing and bonding arrangements (i.e. TT).
In any event the oil pipe should be bonded.

 

[Q.S.]

Wirepuller is correct - your equipotential zone is within the house, you do not want to make it any bigger, or you can get to the stage where you put a potential where there is no need for one.
It is always correct to bond at point of entry to the building(s) and if it does not come into to the building leave it alone.

 

[Engineer54]

I'll take issue with this.
It is not possible to have an 'equipotential zone ' in an external situation...(such as surrounding an external boiler).....in such a situation the boiler is surrounded by the general mass of earth so it would be pointless trying to create an equipotential zone by bonding the oil line.
The equipotential zone is in the building , and the heating pipes coming from the boiler introduce an earth potential...(possibly from the oil line)....therefore it is correct to main bond the heating points at the point of entry.

Maybe i didn't read the OP's post too well!! lol!! I was under the impression that the boiler was situated/located within an external outbuilding of some kind, or even an outside cupboard type affair that is within the house boundaries but only accessible externally. Can't say i've ever seen an outside/externally mounted combi boiler, so never considered such an installation.

So if this is indeed the case, Yes your correct in what your saying above...

 

[Deleted member 9648]

To my mind, if the oil pipe is considered an extraneous-conductive-part, it will require bonding.
If the boiler is within the building, the oil pipe will require bonding as close as practicable to where it enters the building, preferably within 600mm.
If the boiler is in another building, then it may be that it should be treated as a separate installation, and will require it's own earthing and bonding arrangements (i.e. TT).
In any event the oil pipe should be bonded.

I disagree......if it's in an external situation it is impossible to create an equipotential zone,thats the whole point of bonding. If the boiler is completely external the potential from an oil line will be introduced to the equipotential zone via the heating flow/return....they will need bonding at the point of entry to the building.

@E54.......external stand-alone boilers are quite common around here...and I always bond incoming pipes at the point of entry to the building.

 

[Engineer54]

@E54.......external stand-alone boilers are quite common around here...and I always bond incoming pipes at the point of entry to the building.

That's fine wirepuller, it's just that i've personally never seen them, so didn't consider such an installation/situation in my reply/post!! I would still earth any metal oil tank and/or pipes though, if only for tanker equalisation filling purposes.

 

[Q.S.]

ERRRHHH NO - The tanker will if necessary earth to the tank , how ever if you have earth leakage (parallel paths and all that) from any electronic equipment or a low fault you will be putting a potential into the tank which may or may not cause a problem.

 

[Engineer54]

Every filling station, commercial or private that i have been involved with (and their have been many) had the fuel tanks earthed via Rod mat or other form of electrodes connected to both the tanks and a common reel lead position ( a statutory requirement in most of the countries i've worked within).

Because the reel lead is connected between the tanker and the underground tanks first, before any filling pipes are connected, both the tanker and tanks will be at the same potential!! It doesn't matter if the reel lead is mounted on the tanker or the installation being filled...

 

[Knobhead]

Not really relevant in this situation but every tanker discharge/loading point I’ve dealt with would have the static equalisation point fitted. In our case we were dealing with granulated or powdered product. Where the danger is after the pipe is connected and the product is travelling through causing some nasty static build up.