16mm T & E flat supply

[shocking_eg]

At the meters which are just inside entrance lobby to communal staircase on ground floor, 1 flat on 1st floor & 1 on the 2nd floor!

Okes, and you say each flat is on its own DNO supply ? Or a 3phase split etc... ?

 

[craig1000]

One single phase supply into communal mains cupboard, split out of head with two sets of tails to two DNO meters! One set of tails then to isolator & up to top flat, one set to CU in communal cupboard feeding some communal circuits some level 1 flat circuits as well as a sub mains to level 1 flat CU!
Cafe is a complete separate DNO supply in a separate location!

 

[shocking_eg]

At the meters which are just inside entrance lobby to communal staircase on ground floor, 1 flat on 1st floor & 1 on the 2nd floor!

Well as both flats come off one supply, in my opinion bonding at the intake after the meter seems perfectly fine to me for the two flats.


But the cafe should be bonded off its own supply If you say it's different to the flats supply.

 

[rattlehead85]

Confirm adequacy of 6mm earthing conductors to the flats by using the adiabatic equation. The fusing arrangements are incorrect. Main fuse being 60A serving two s/f 60A isolators. This is a discrimination issue. The main fuse and supply tails idealy need to be uprated to 100A to eliminate this although this warrants only a C3 on an EICR. The 6mm water bonding would be sufficient as long as there are no signs of deterioration or signs of overheating at the points of connection if this is a TN-C-S system.

 

[craig1000]

Thanks rattle head, yeah have logged the 60amp fuse etc & the need to uprate! The whole place is a bit of a mess, last tested 2 years ago according to stickers on all CU's! Some of it although IMO rough as assholes though I guess they may get away with! Would love to see previous cert but not available! New tenant taken property on after previous had gone bust running the cafe below! Should have 3 CU's IMO, one small one for communal stair case lighting & power! 1 in each in flat! Instead there is one in top flat fed via isolator & then they lighting circuit from that flat serves communal lights as well!
CU in communal hall cupboard serves FA panel Spur, lighting in 1st floor flat & ring & immersion spur + a CU int 1st floor flat feeding cooker & 4 radial single sockets for heaters in each room! ;-/

Will confirm using adiabatic! System is T-N-S

 

[rattlehead85]

Sounds like a right dogs dinner. I tend to agree with the c.u set up you suggest but justifying doing that on personal preference if the existing installation stands up to BS7671 may prove difficult let alone the cost of altering the wiring configuration and associated disturbance to the building fabric.

 

[craig1000]

Yeah I know ;-(
To be fair customer is really good & is keen to get things not just passed but up to current regs & more practical!
for example the top flat is to be letted out yet the communal lights are fed from it so the tenant would have a good cause for a right old whinge as they would be paying for the communal lights & the lower flat when letted would be paying for FA panel! Minimal cost I know but still a good gripe from a tenant!
Will plod on through do report etc & then also give recommendations!

 

[rattlehead85]

Surely the FA panel needs to be on either a communal board set up or its own dedicated supply and not from flat 1. If a fault condition occurs within flat 1 ( pending how the c.u. is layed out) this could cause power loss to the panel and may leave the system on battery drain.

 

[craig1000]

Yeah I know, as it is it is on the CU in the communal cupboard on non rcd side but this CU alsi feed multiple circuits in flat 1 as well as the CU in flat 1 ;-(

 

[Engineer54]

That seems a totally pointless task

You will end up making the resistance higher with the longer cable runs

And it all goes back to the same place anyway !

What's totally pointless? And no it doesn't go back to the same place!! The internal bonding of each flat is taken from the service pipes as they enter the flats, (or near too) to the the consumer unit (or MET earthing block) of the flat!! Same as you would do in any other domestic installation. They Don't go down to the main intake point!!


I don't understand why you need to disconnect any of the existing bonding that's present??

 

[Silly Sausage]

I'm thinking...scrap the 17th edition multiple joke test, there should be a closed book GN8 exam, well they should be all no books written exams.

 

[craig1000]

I don't understand why you need to disconnect any of the existing bonding that's present??[/QUOTE]

I have not said to disc connect any of the previous bonding, just due to the nature of how it is done & the sizes I am confirming its correctness or not!

 

[craig1000]

I'm thinking...scrap the 17th edition multiple joke test, there should be a closed book GN8 exam, well they should be all no books written exams.

You may be referring to me & my in some areas lack of understanding, I would in fact agree with ya! I did 17th earlier this yesr & tbf it is far to easy to pass with out a real proper understanding! I however will admit my lack of knowledge in some areas & always try to learn it as it comes up which is all I can do!