Consumer unit to be moved away from service head

[Chris]

Hi everyone.
I have been asked to relocate a consumer unit from a cupboard outside a house into the inside of the property. The main fuse and meter will be remaining outside however the run is about 6/7 metres long, i believe it states in BS7671 that the meter tails cannot exceed 3m in length.
would this require me to put a separate fused connection unit within the 3m of isolater and then run a 25mm SWA + 16mm earthing conductor from the fused connection unit, to the 6/7m away consumer unit location? If not who knows a better way?
thanks, chris.

 

[Leesparkykent]

Yes i havent ap

Ah my mistake ive just added the rating of the MCBs up

The old school rule of thumb is to exclude the highest rated circuit breaker, add up up the rest of the circuit breakers, times this figure by 0.4 and add this figure to the rating of the highest rated circuit breaker you excluded.

 

[Leesparkykent]

Yes i havent ap

Ah my mistake ive just added the rating of the MCBs up

The old school rule of thumb is to exclude the highest rated circuit breaker, add up up the rest of the circuit breakers, times this figure by 0.4 and add this figure to the rating of the highest circuit breaker you excluded.

 

[Chris]

The old school rule of thumb is to exclude the highest rated circuit breaker, add up up the rest of the circuit breakers, times this figure by 0.4 and add this figure to the rating of the highest circuit breaker you excluded.

Thanks, it comes in at 76.8

 

[Chris]

Considering the OP has told Pete that he has done his 17th and 2391 bit concerning.

Still learning!

 

[Toneyz]

What is the main REC fuse rating 100A? if so need 100A metal switch-fuse with 80A fuse.

Still learning!

Not a dig Chris but thought that you would have learnt regarding diversity prior to you doing 17th and 2391.

 

[Ian1981]

I often use the highest load such as a shower for example then add 40% of the remaining loads.
Similar to lees method maybe Just the formula transposed

 

[Chris]

What is the main REC fuse rating 100A? if so need 100A metal switch-fuse with 80A fuse.

Not a dig Chris but thought that you would have learnt regarding diversity prior to you doing 17th and 2391.

Yes main fuse rating is 100A, thank you.

And i know it wasnt a dig! I work for a housing association and havent done any maximum demand calculations since my college days.

 

[Toneyz]

Yes main fuse rating is 100A, thank you.

And i know it wasnt a dig! I work for a housing association and havent done any maximum demand calculations since my college days.

Fair enough as said Pete said no profile anyway know where you're coming from now and yes if not doing all the things learnt at college you soon get rusty no offence meant Chris.
I would run a three core SWA the only thing if you are using 25mm is that the core that you are using for the earth it fits in the main earth terminal.

 

[Chris]

Fair enough as said Pete said no profile anyway know where you're coming from now and yes if not doing all the things learnt at college you soon get rusty no offence meant Chris.
I would run a three core SWA the only thing if you are using 25mm is that the core that you are using for the earth it fits in the main earth terminal.

Yes i only made this the other day i am yet to fill in all the details, will get round to it soon.
Yeah the supervisors do all the drawings and calculations so the rust appears to have set in haha! No offence taken.
That was my thought too im almost certain it will be too large for the MET i may have to figure something out for that.

 

[Octopus]

The old school rule of thumb is to exclude the highest rated circuit breaker, add up up the rest of the circuit breakers, times this figure by 0.4 and add this figure to the rating of the highest circuit breaker you excluded.

I find multiplying by 0.25 a better calculation ......

 

[Midwest]

The old school rule of thumb is to exclude the highest rated circuit breaker, add up up the rest of the circuit breakers, times this figure by 0.4 and add this figure to the rating of the highest circuit breaker you excluded.

That sounds just as ridiculous as Appendix A in the OSG

 

[Bellendian]

I've not come across a 'standard' house yet that can't live on 16mm and 60A, even big ones. Max demand calcs are a pita, you can talk yourself into all sorts of absurd figures, but the reality is that these scenarios never arise, and on the off chance that they do, the dno aren't daft enough to let your error damage their network beyond the fuse in the cutout.

 

[buzzlightyear]

Yes main fuse rating is 100A, thank you.

And i know it wasnt a dig! I work for a housing association and havent done any maximum demand calculations since my college days

http://www.napitonline.com/downloads/CP 4 07 P 10-11 16th Diversity.pdf

 

[Pete999]

no worries pete, i served a 4 year apprenticeship and have been qualified for 2 years and have my 17th edition (18th booked in), the 2357 NVQ and just recently passed the Inspection and testing 2391.

Thanks Chris

 

[telectrix]

Yes i only made this the other day i am yet to fill in all the details, will get round to it soon.
Yeah the supervisors do all the drawings and calculations so the rust appears to have set in haha! No offence taken.
That was my thought too im almost certain it will be too large for the MET i may have to figure something out for that.

you can fit a reducing lug.