Main Bonding

[EFLImpudence]

I thought that the gas pipework has to be bonded has it enters the house ,

Ah ok yes, it does because it is entering the house - not because it is going to the boiler.

 

[Spikes Mavic]

Ah ok yes, it does because it is entering the house - not because it is going to the boiler.

The boiler gas pipework is the only place to fit a bond inside the house , it comes into the house under the floor boards and up into the kitchen to the boiler

 

[SUNRAY]

Oh my goodness.

each building has to be treated as a zone in it's own right, therefore:

In the garage there is a MET bonded to the CU and extraneous metalwork

In the house there is a MET bonded to the CU and extraneous metalwork

The fact that the garage feeds gas to the house is irrelevant

The fact that the house feeds electricity to the garage is irrelevant

My interpretation of the various documents (and I don't claim to know every single detail) is:

In the garage I have shown 2 wires in green to the gas pipes and alternatively one wire in purple to both pipes as long as it is in one piece, this can be achieved by not cutting it or some other means of making the join between the 2 wires permanent ie by putting both wires into a single crimped connector or soldering/sweating.

Also it is permissable to use the CU earth bar as the MET if there are sufficient adequately sized terminations.
The earth from house to garage should be 10mm² due to the gas bonding. Ideally without a joint but not a necessity.

 

[SUNRAY]

...
Anyway, if three are required then this would comply:

View attachment 381844

This arrangement does not comply and never has.

 

[Spikes Mavic]

Oh my goodness.

each building has to be treated as a zone in it's own right, therefore:

In the garage there is a MET bonded to the CU and extraneous metalwork

In the house there is a MET bonded to the CU and extraneous metalwork

The fact that the garage feeds gas to the house is irrelevant

The fact that the house feeds electricity to the garage is irrelevant

My interpretation of the various documents (and I don't claim to know every single detail) is:View attachment 381880
In the garage I have shown 2 wires in green to the gas pipes and alternatively one wire in purple to both pipes as long as it is in one piece, this can be achieved by not cutting it or some other means of making the join between the 2 wires permanent ie by putting both wires into a single crimped connector or soldering/sweating.

Also it is permissable to use the CU earth bar as the MET if there are sufficient adequately sized terminations.
The earth from house to garage should be 10mm² due to the gas bonding. Ideally without a joint but not a necessity.

The only thing in question now, is where to fit the 10mm bonding to the gas pipe in the house, I can't fit a bond to the gas pipe has it enters the house, it comes in under the floor boards, so was asking now if bonding to the gas feed to the boiler will be ok !

 

[Spikes Mavic]

This arrangement does not comply and never has.

Your attachment is what I am doing !

 

[SUNRAY]

The only thing in question now, is where to fit the 10mm bonding to the gas pipe in the house, I can't fit a bond to the gas pipe has it enters the house, it comes in under the floor boards, so was asking now if bonding to the gas feed to the boiler will be ok !

There are differences between documents on this point,they all say as it enters the house but some duplicate the requirement at the meter, ie within 600mm and before the first tee, others say

as near as practicable to the point of entry of that part into the
premises.

So if the position at the boiler is the earliest practical position then so be it

But I thought that the 10mm bonding from the MET to the Meter had to be continuous, if I put in a earthing terminal before the meter it wil have broken the continuous run !

Yes it does have to be continuous, but it is to the MET in the same building, The link between the 2 METs is different rules

That is good then so will pull through a the 10mm from the MET to a earthing block in the garage, then 10mm to the CU, outlet pipe of gas meter, and the gas riser , job done !.
ps: The difficult part is attaching a bond to the riser, not sure how to go about doing that, would have to be some sort of heavy clamp that will dig into the steel pipework, just the normal SS steal straps wond do I suspect !

That is correct but if you are describing my sketches purple wire then yes a single wire as in the description or 2 seperate wires as in my sketches green wires.

 

[Spikes Mavic]

There are differences between documents on this point,they all say as it enters the house but some duplicate the requirement at the meter, ie within 600mm and before the first tee, others say

So if the position at the boiler is the earliest practical position then so be it

Yes it does have to be continuous, but it is to the MET in the same building, The link between the 2 METs is different rules

That is correct but if you are describing my sketches purple wire then yes a single wire as in the description or 2 seperate wires as in my sketches green wires.

Am doing the 2 green wires, and tks for making it clear, it was getting a bit messy

 

[SUNRAY]

Am doing the 2 green wires, and tks for making it clear, it was getting a bit messy

You are welcome.

For what it's worth I'm sorry that the waters were so badly muddied for you when your question was basically answered in post #8

 

[EFLImpudence]

Yes it does have to be continuous,

No it doesn't.

In fact other conductive-parts may (are allowed to) be used as a main bonding conductor - including e.g the SWA armour, metal building parts, even a water pipe (not a gas pipe though) - so how could they be continuous?

 

[JohnW2]

Oh my goodness. .... each building has to be treated as a zone in it's own right, therefore:

As you presumably saw, I had that discussion with EFLI and, although I don't think either he or I are absolutely certain, as I see it ....

In the garage there is a MET bonded to the CU and extraneous metalwork
In the house there is a MET bonded to the CU and extraneous metalwork

My view is that if the house's earth is 'exported' to the garage, then there is only one true MET - that to which the DNO's earth (or,if TT, the earth rod) is connected. There might be things that resemble a "MET" in other places, which are electrically connected to the actual MET, but they lack the "M" and therefore aren't METs (any more than an earth terminal in a JB or accessory is).

I have explained how I believe that situation (exported earth, so only one MET) impacts on the bonding business - in particularly my view that, if there is only one MET, it is not necessary to bond both ends of a short length of pipe to that (single) MET.

 

[pete01]

I would just run a 10mm earth into the garage and onto the gas meter.

 

[JohnW2]

This arrangement does not comply and never has.

Since when, and why? I would be totally comfortable with that.

 

[JohnW2]

No it doesn't.

As far as I am aware, BS 7671 has never said that bonding conductors must be 'continuous'. If I recall correctly, the myth arose because there was a day when the wretched OSG (but not BS7671) said this, but it's not even in the OSG now.

Let's face it, people are extremely unlikely to simultaneously touch the MET and an extraneous-c-p. Main bonding exists to protect people whole simultaneously touch an extraneous-c-p and an exposed-c-p - there will often be umpteen (usually 'screwed') joints in the path between the extraneous- and exposed-cps (probably a very minimum of 4, often/usually more), so one or two additional ones in the bonding conductor (which is part of that path) is really neither here nor there.

 

[Spikes Mavic]

Completed 10mm from MET to garage .