EICR LOCAL BONDING FLATS

[APElectrical]

I’m sure this has been covered a squillion times before but advice please. EICR on block of 5 flats all with separate electrical supplies & meters. One boiler serving hot water via one system to all flats. Main bond to water and gas on entry to building. There is no bonding locally within the flats from the flats DB . C3 for no local bonding as shared water / gas supply? Or C2 as the zone within the flat itself needs dedicated local bond. Thanks

 

[timhoward]

I’m not sure any regs have been broken as both gas and water are bonded at point of entry?
Supplementary bonding may be needed locally in each flat depending on RCD protection and presence of anything that needs bonding.

 

[Pretty Mouth]

I’m sure this has been covered a squillion times before but advice please. EICR on block of 5 flats all with separate electrical supplies & meters. One boiler serving hot water via one system to all flats. Main bond to water and gas on entry to building. There is no bonding locally within the flats from the flats DB . C3 for no local bonding as shared water / gas supply? Or C2 as the zone within the flat itself needs dedicated local bond. Thanks

Good question.

411.3.1.2 gives us:
In each installation main protective bonding conductors complying with Chapter 54 shall connect to the main earthing terminal extraneous-conductive-parts including....

Is the whole building one installation? Or, is every flat, and the distribution/communal areas, each installations in their own right?

I think the latter. I think it's possible, through strategically placed plastic sections in the pipework, and earthing problems in one flat, for pipework to introduce a potential into another. I would like to see bonding in each flat.

 

[Pete999]

Good question.

411.3.1.2 gives us:
In each installation main protective bonding conductors complying with Chapter 54 shall connect to the main earthing terminal extraneous-conductive-parts including....

Is the whole building one installation? Or, is every flat, and the distribution/communal areas, each installations in their own right?

I think the latter. I think it's possible, through strategically placed plastic sections in the pipework, and earthing problems in one flat, for pipework to introduce a potential into another. I would like to see bonding in each flat.

 

[timhoward]

411.3.1.2 also gives us
"where an installation serves more than one building the above requirement shall be applied to each building"
This helps us a bit with the definition of installation and the possibility it is much bigger than one flat.

While I totally agree a potential could be introduced within the building if the pipework is insulated at any point, I thought the main intent of these regs is preventing introducing a potential from outside the building or exporting a potential outside the building.

I do agree that common sense says each flat would be best off with the services bonded so a C3 doesn't seem unreasonable.

The definition of installation from part 2 -
Part 2 - "Installation - see Electrical Installation"
"Electrical installation - An assembly of associated electrical equipment having coordinated characteristics to fulfil specific purposes"
...not sure that helps much!

Love to hear more views on this though - it's a very interesting question.

 

[loz2754]

The NICEIC official view is that each flat should be main bonded inside the flat if there are extraneous parts entering the flat, regardless of whether there is bonding at the source on the ground floor.

Which makes sense, as the requirement for main bonding refers to an extraneous conductive part that is likely to bring a potential (mainly earth potential, but not exclusively) into the installation. A potential could be introduced into the flat from another flat, in certain circumstances, for example if there are insulating sections of pipework in the other flat(s).

In other words, it's better to take the belt and braces approach.