Earthing the gas mains

[tusharinuk]

I recently replaced the boiler in our first floor flat with a combi. The guy who did it gave me a certificate for it, but also has put in an observation stating that the gas mains is not earthed on a different piece of paper.

1. Is this a serious problem?
2. If I were to rent out the flat, will this stop me from getting a gas safety certificate?
3. If I were to mend this, does it mean that I will need to get an electrician to connect an earthing lead somewhere from the mains meter in the hallway, to the kitchen (running behind walls and floors which might need to be opened up to conceal the earthing cable)
4. There is a water mains pipe which is earthed from the mains and is near the kitchen. Can I get the electrician to extend this to the gas main?

The wiring in the flat was done in 1980 regs.

Sorry I am not an electrician, but trying to understand the easiest way of resolving this issue, if at all it needs to be. We may be forced to rent the property soon, so want to get this sorted if required.

Any suggestions will be helpful. If this has already been discussed, please point me to the right forum as I tried searching but probably due to lack of right words ended up here.

with regards
Taz

 

[riveralt]

This is the type of 'bonding' you should expect to be installed in your property.
//www.diynot.com/wiki/electrics:main_equipotential_bonding
If any are missing then you should get someone in connect the correctly sized cables.

 

[PrenticeBoyofDerry]

1. Is this a serious problem?

Yes!

2. If I were to rent out the flat, will this stop me from getting a gas safety certificate?

probably not, but your property is not electrically safe, so you could end up in court.

3. If I were to mend this, does it mean that I will need to get an electrician to connect an earthing lead somewhere from the mains meter in the hallway, to the kitchen (running behind walls and floors which might need to be opened up to conceal the earthing cable)

depend where the gas meter pipe on the consumer side is in relationship to the MET or consumer unit.

4. There is a water mains pipe which is earthed from the mains and is near the kitchen. Can I get the electrician to extend this to the gas main?

No! but they can be connected together, the earth cable must be in one continues length piece, no joints or cuts in the cable, not even at the earthing clamps.

Any suggestions will be helpful.

The main earth bonding to the gas pipe needs to be made as close as practical to the pipe work on entering the building and after the the gas meter, also if any branches are the pipe they bond should be made before them to.
Ideally within 600mm of entering the property and after the gas meter.

 

[PrenticeBoyofDerry]

out of interest what type of supply earth have you?
what size is the main earth bonding in place at the moment?
and what size earthing conductor do you have from the supply earth to you MET/CU?

 

[PrenticeBoyofDerry]

4. There is a water mains pipe which is earthed from the mains and is near the kitchen. Can I get the electrician to extend this to the gas main?

No! but they can be connected together, the earth cable must be in one continues length piece, no joints or cuts in the cable, not even at the earthing clamps.

if the existing cable passes past the gas pipe before connecting to water, you could clamp it on if enough slack in cable

 

[PrenticeBoyofDerry]

delete

 

[tusharinuk]

4. There is a water mains pipe which is earthed from the mains and is near the kitchen. Can I get the electrician to extend this to the gas main?

No! but they can be connected together, the earth cable must be in one continues length piece, no joints or cuts in the cable, not even at the earthing clamps.

if the existing cable passes past the gas pipe before connecting to water, you could clamp it on if enough slack in cable

Thanks, I wish it was, But the water pipe comes first and then the gas pipe. Assuming that the MET (which I haven't seen yet) is at the door with the electric meter to the flat.

 

[PrenticeBoyofDerry]

Assuming that the MET (which I haven't seen yet) is at the door with the electric meter to the flat.

It could be or it may be with the CU if the CU is a different location.
So you have a flat, as there was another alternative, which would mean routing the cable externally and back in to the property.
Not my favourite option as it's open to mechanical damage.
The main earth bonding does not need to buried or concealed, if there is accessibility to run the cable behind or under kitchen cabinets it can be done.

 

[tusharinuk]

Not sure. Will check this out today. Is this how a MET looks like (just picked a reference image of web to compare)?

 

[JohnW2]

4. There is a water mains pipe which is earthed from the mains and is near the kitchen. Can I get the electrician to extend this to the gas main?

No! but they can be connected together, the earth cable must be in one continues length piece, no joints or cuts in the cable, not even at the earthing clamps.

That's an assertion we often see, and I think we can agree that it represents good/best practice - and we can also all think of scenarious related to work on gas/water pipes when an MPB conductor 'joined at the earthing clamp' might present a hazard. However, is there actually any regulation, or even guidance, which forbids this ?- I've never been able to find any in either BS7671 or the OSG.

Kind Regards, John.

 

[tusharinuk]

4. There is a water mains pipe which is earthed from the mains and is near the kitchen. Can I get the electrician to extend this to the gas main?

No! but they can be connected together, the earth cable must be in one continues length piece, no joints or cuts in the cable, not even at the earthing clamps.

That's an assertion we often see, and I think we can agree that it represents good/best practice - and we can also all think of scenarious related to work on gas/water pipes when an MPB conductor 'joined at the earthing clamp' might present a hazard. However, is there actually any regulation, or even guidance, which forbids this ?- I've never been able to find any in either BS7671 or the OSG.

Kind Regards, John.

Also will it be better to have a earth wire connecting the gas main running from the water mains rather than not having any all?

 

[JohnW2]

Also will it be better to have a earth wire connecting the gas main running from the water mains rather than not having any all?

That is clearly true - although some would, of course, argue that this is not a good reason for not doing it 'properly'.

Another possibility for an electrician who was competant at, and happy with, crimping of cables would be to cut the present cable just short of the connection to the water pipe, join a new length of cable by crimping, and then use that new bit of cable to connect to both water and gas pipes, without a break - or even join the new bit of cable with an (accessible) (screw terminal) junction box (not really any 'worse' than the screw terminal connection which exists at the MET) - although those approaches obviously would still not satisfy those who believe that an unbroken cable is required.

Kind Regards, John.

 

[tusharinuk]

Also will it be better to have a earth wire connecting the gas main running from the water mains rather than not having any all?

That is clearly true - although some would, of course, argue that this is not a good reason for not doing it 'properly'.

Another possibility for an electrician who was competant at, and happy with, crimping of cables would be to cut the present cable just short of the connection to the water pipe, join a new length of cable by crimping, and then use that new bit of cable to connect to both water and gas pipes, without a break - or even join the new bit of cable with an (accessible) (screw terminal) junction box (not really any 'worse' than the screw terminal connection which exists at the MET) - although those approaches obviously would still not satisfy those who believe that an unbroken cable is required.

Kind Regards, John.

Appreciate the thoughts. In fact I was wondering : if you are allowed to put 4 earth wires into a MET and then one to go to the actual earth itself is considered as "continuous" connection to the earth. Then I can use a MET (no clue to what it costs) at the water pipe to connect the earth lead coming from gas pipe. If screwing wires in MET is safe and maintains the desired continuity, then it will be safe anywhere ?

(This is a just a logical thought in my mind and and I do respect any opinion that professionals are giving here as well as the starndard that need to be followed.)

If an MET is considered 'electrically continuous

 

[JohnW2]

Appreciate the thoughts. In fact I was wondering : if you are allowed to put 4 earth wires into a MET and then one to go to the actual earth itself is considered as "continuous" connection to the earth. Then I can use a MET (no clue to what it costs) at the water pipe to connect the earth lead coming from gas pipe. If screwing wires in MET is safe and maintains the desired continuity, then it will be safe anywhere ?

I'm certainly not going to argue with your common sense. Those who think that 'continuous cables' are required would probably not be happy with the joint (at present MET) in the cable from 'actual earth' to the newly-positioned MET you are postulating. Furthermore, there can, by definition, only be one 'MET' ('Main Earthing Terminal'). Hence, in the minds of the purists, if you moved the MET close to the pipes, you would theoretically have to run a cable from that moved MET back to the consumer unit (which, to my mind, would be plain daft!), rather than from the 'old MET'.

Kind Regards, John.

 

[sparkwright]

4. There is a water mains pipe which is earthed from the mains and is near the kitchen. Can I get the electrician to extend this to the gas main?

No! but they can be connected together, the earth cable must be in one continues length piece, no joints or cuts in the cable, not even at the earthing clamps.

if the existing cable passes past the gas pipe before connecting to water, you could clamp it on if enough slack in cable

I don't think it would be very wrong to extend the cable at the water with a butt crimp.