Mains cable to consumer unit top floor flat

[JJONESY4]

Im starting a re-wire of a top floor flat, they have run an 16mm T&E with a 6mm earth from the ground floor to the 3rd floor feeding the CU, replacing this cable is practically impossible as there is no way of getting down without going through other flats. Looking for some advice of how others have gotten around this?
Do I fit a small board at the main incoming downstairs and protect the cable with a time delayed RCD?

 

[DPG]

Im starting a re-wire of a top floor flat, they have run an 16mm T&E with a 6mm earth from the ground floor to the 3rd floor feeding the CU, replacing this cable is practically impossible as there is no way of getting down without going through other flats. Looking for some advice of how others have gotten around this?
Do I fit a small board at the main incoming downstairs and protect the cable with a time delayed RCD?

Will a time delayed RCD meet regs?

At the end of the day if you can't meet regs then the cable may need replacing.

 

[westward10]

What is currently protecting the cable?

 

[7029 dave]

What is currently protecting the cable?

At a guess 60A hrc fuse in a switch fuse?

 

[7029 dave]

Im starting a re-wire of a top floor flat, they have run an 16mm T&E with a 6mm earth from the ground floor to the 3rd floor feeding the CU, replacing this cable is practically impossible as there is no way of getting down without going through other flats. Looking for some advice of how others have gotten around this?
Do I fit a small board at the main incoming downstairs and protect the cable with a time delayed RCD?

Hi, being its top floor, could you not run SWA cable from downstairs drill out and run up externally into loft space and drop down to CU position.
The only problem suppose would be gaining permission from the L/Lord to run a cable up the building worth making inquires or even running internally up landing stair case if possible.

 

[Pretty Mouth]

What is the earthing arrangement for this flat @JJONESY4 ?

 

[JJONESY4]

Hi, being its top floor, could you not run SWA cable from downstairs drill out and run up externally into loft space and drop down to CU position.
The only problem suppose would be gaining permission from the L/Lord to run a cable up the building worth making inquires or even running internally up landing stair case if possible.

Hi, thanks for reply problem is it’s in central London so there’s no chance of running a cable directly through the landings or exterior as they won’t alow it.

 

[JJONESY4]

What is the earthing arrangement for this flat @JJONESY4 ?

Tns

 

[JJONESY4]

At a guess 60A hrc fuse in a switch fuse?

Correct

 

[JJONESY4]

What is currently protecting the cable?

Just a 60a fuse from the incoming which is down 3 stories.

 

[westward10]

So what is the problem?

 

[7029 dave]

So what is the problem?

The distribution circuit is not compliant t&e not protected IMO this should be a departure. If that the supply cable shouldn't stop anyone rewiring the flat.

 

[westward10]

Isn't protected by what, a 30ma RCD?
Not going to be part of the job if you are rewiring the flat.

 

[7029 dave]

Isn't protected by what, a 30ma RCD?
Not going to be part of the job if you are rewiring the flat.

Yes no RCD protection

 

[davesparks]

Do I fit a small board at the main incoming downstairs and protect the cable with a time delayed RCD?

What would the RCD be for? Is it a TT system?

 

[westward10]

Yes no RCD protection

Submain is fine so needn't be included in the installation.

 

[cliffed]

sub main looks like it will need Rcd protection, the other issue is the size of the cpc which will be ok if MBPC are not required at the Flat.

 

[littlespark]

The only reason it may need rcd protection is if it’s buried <50mm inside the other flats, and we don’t have that information.

It’s no different than regular meter tails in terms of mechanical protection… it’s just a long length, which is taken care of by the 60A fuse.

 

[DPG]

OP - is this T&E run on the surface or in conduit all the way? Or is any of it below the surface?

I'm guessing not as you were talking about changing the cable or adding RCD protection.