Main Bonding Question

[egg661]

I am sorting the wiring installation in my house, it is a Victorian terrace circa 1880. TT supply and the main gas incomer is at the front of the house and the main water incomer is at the back. It will be a massive problem to bond the incomers at 600mm of point of entry due to running in the cables.

So i have bonded them at the new combi boiler installation which is situated in the airing cupboard upstairs and run back the CU (17th Edition spec).
i have tested the continuity of all the gas, water pipes and central heating around the house back to the CU and all is OK.
Do you think that this is acceptable due to the difficulty of getting to the point of entry of the incomers?

Regards Mark

 

[sparks1234]

Itrs better than nought but its outside of the regulations, problems in the future could be that if the installation gets altered then the earth may get disconnected if the pipe are unused

 

[Mac]

I am sorting the wiring installation in my house, it is a Victorian terrace circa 1880. TT supply and the main gas incomer is at the front of the house and the main water incomer is at the back. It will be a massive problem to bond the incomers at 600mm of point of entry due to running in the cables.

So i have bonded them at the new combi boiler installation which is situated in the airing cupboard upstairs and run back the CU (17th Edition spec).
i have tested the continuity of all the gas, water pipes and central heating around the house back to the CU and all is OK.
Do you think that this is acceptable due to the difficulty of getting to the point of entry of the incomers?

Regards Mark

Where is the CU situated.If you are sorting all the wiring out at the house,can't you lift the boards.How did they get the gas supply to the new combi boiler,or was there one already there

 

[Gravid]

Couldn't you just write it on the installation cert that its a deviation from the regs and state where its bonded, doesn't mean its unsafe. Surely practicality comes into it.

 

[stretchyboy]

Couldn't you just write it on the installation cert that its a deviation from the regs and state where its bonded, doesn't mean its unsafe. Surely practicality comes into it.

Very true, it would be helpful if you put notice/ sticker/ label at the points where the earth connection should be to indicate where the connection actually is. This ought to stop the gas-board man making you look like a lemon to your customer when he says it isn't fitted.............. just a thought

 

[acat]

Think the actual wording is within 600mm of the meter on the consumers side or as close as practical so the practicality as mentioned above comes into it





Chris

 

[egg661]

The CU is mounted in the stairwell so is easily accessible by lifting the upstairs boards.
The downstairs flooring is laminated so will be a big pain to lift, plus a wall would also have to be chased out.(where gas incomer is)
The kitchen is at the back where the water incomer is and is an extension, there is no roof space access and the floor is tiled with electric underfloor heating, so again major problem getting cable to incomer.
(and is also decorated nicely ).
So to me makes sense to main bond at the new combi boiler installed upstairs were the mains water and main gas supply are easily accessible.
No need for supplementary bonding as 17th edition board installed.
I know that it deviates from the regs but surely it makes for less disruption and is still safe?
Thoughts please
Regards Mark

 

[demolution4o]

It's only code 4 in the PIR, so it\s not a big deal if it's not at place. Just make sure the Zs readings are OK and u have rcd protection

 

[scotsparky]

The CU is mounted in the stairwell so is easily accessible by lifting the upstairs boards.
The downstairs flooring is laminated so will be a big pain to lift, plus a wall would also have to be chased out.(where gas incomer is)
The kitchen is at the back where the water incomer is and is an extension, there is no roof space access and the floor is tiled with electric underfloor heating, so again major problem getting cable to incomer.
(and is also decorated nicely ).
So to me makes sense to main bond at the new combi boiler installed upstairs were the mains water and main gas supply are easily accessible.
No need for supplementary bonding as 17th edition board installed.
I know that it deviates from the regs but surely it makes for less disruption and is still safe?
Thoughts please
Regards Mark

Why no need for suplimentary bonding due to 17th edition boaard??? what about fault voltage on exposed coductive parts? I suggest you read 415.2 on the BRB and dont rely on RCds.

As for your main Bonding have a look at 411.3.1.2 and reg 544.1.2

 

[NoSparks]

Reg 415.2 only defines what supplementary bonding is.

Reg 411.3.2.6 Requires the use of Supplementary bonding only if the Automatic disconnection times specified in Reg 411.3.2.2 - 4 cannot be met.

An RCD as defined in 411.5.3 will give assured disconnection provide the resistance path (through the extranious metal to earth) is no greater than 1667Ohms.

I think this is what is coloquially referred to as a 17th Edition Board.

Geoff

 

[scotsparky]

Yes in a new install not a problem but would you go into a 10 year old house to do a PIR and say you would have to change the DB as there is no RCD for example the bathroom lights?

In this case its an old house so check the bonding with the long lead and prove if ADS can be acheeved before saying "Board change!" you will look like a fool if they get a second opinion and ADS can be acheeved and you didnt check.

Also sparks remeber with the RCD the book says max 1667 ohms but watch out for the touch voltage on exposed metalic parts and extranious metalic parts. less than 50v