Diversity

[Andy™]

Thanks everyone much appreciated, the only reason for the Diversity question is that NAPIT have slapped a non compliance on me for exceeding manufacturers recommendations on the 100amp main fuse LOL

what does the manufacturer say?

 

[Andy™]

The move to all electric living is fraught with problems not least the local cabling infrastructure. Chatting to a number of DNO guys over the last few years they have all said that the local cable networks will need major reinforcement to cope,

there#s a few street round here wired in 4mm from the cable in the street. cable in street is something like 25mm. no chance of that working if everything goes fully electric

 

[kerching]

Thanks everyone much appreciated, the only reason for the Diversity question is that NAPIT have slapped a non compliance on me for exceeding manufacturers recommendations on the 100amp main fuse LOL

Oooooh I'd like to meet him and it would be a very different kind of slap!
I suppose they are still quoting 10 x 100W lamps for a lighting circuit as well

 

[Phoenix]

If he wants I can show him a retirment living complex with 60 self contained flats, all with their own cooking facilities, some with electric showers where I tallied up the breakers and worked out diversity properly, would need an onsite 1mvA sub, and where if I was designing I'd probably think 250A/phase sounds about right, but where in actual fact we found the head has had 100A fuses in it since the place was built in the mid 80s.

As a side note, I had a few years working alongside the chap who as a young-ish man had worked on the install job, he retired in February, a 1985 install doesn't sound that old.... but its the best part of a working lifetime away....

 

[binky]

Maybe we've all been doing wrong for years

I gave up years ago

 

[Murdoch]

So we have to install more circuits so as to reduce the amount of Earth leakage / tripping

yet diversity calcs haven’t been updated

go figure

 

[mort2376]

So we have to install more circuits so as to reduce the amount of Earth leakage / tripping

Not only that we now have to space rcbos or equivalent out so long use ones are not together.

So no more nicely arranged boards going from large to small unless you put spacers inbetween.

It's getting crazy

 

[Murdoch]

It's crazy

edited that for you

 

[top banana]

Is it the 100A DNO fuse / service head they are putting as a non compliance or the 100A main switch in the CU

its the consumer unit 100amp NAPIT inspector says i'm over the manufacturers recommended ampage

 

[top banana]

I agree with you, but there seems to be a different agenda and method of working these days

When you look at the OP's figures they look to be very generous if not optimistic and probably the installation will never come close to the overall level indicated

This is more likely the NAPIT inspector has to find something and he was struggling so got a bit petty

yea and now I have to £295 for another assessment visit

 

[mort2376]

yea and now I have to £295 for another assessment visit

I would definitely put in a complaint formally to Napit and request that you are reassessed for free as that is totally ridiculous.

It's sounding like the olden days of the NICEIC and their own rules.

I know someone who was with NIC who failed their assessment because they had used the black in a 3 core cable as a neutral (sleeved blue) instead of the grey.

It was a recommendation that you did it that way, but what is the issue if its identified ?

I always thought it was an odd recommendation as black was neutral in old money !

 

[poni]

I always thought it was an odd recommendation as black was neutral in old money !

but when the colours changed we were told not to use the black as neutral, and to use the grey, this would denaturalise the black ( as its now a live conductor) and would be less confusing over time,

 

[mort2376]

but when the colours changed we were told not to use the black as neutral, and to use the grey, this would denaturalise the black and would be less confusing over time,

Yes I get that but I still get call out to "I've added a light" and they have cut a 3 core and used brown and black as live and neutral so it's either bang or my new light doesn't work !

But hey brown is the colour of soil so that's the earth. Black is negative on a battery so that's neutral so grey must be live and the bare copper is just for stripping the cable isn't it ?????

 

[Phoenix]

I always thought it was an odd recommendation as black was neutral in old money !

Because before harmonisation we always used the L3 conductor (blue) as neutral and the L2 conductor (Yellow) as earth and it makes sense to continue doing that even though the actual colours have changed. If you have to do a joint, it makes sense to join everything like for like, if you wanted to use black as the neutral then you've got to start doing joints that cross stuff over.

Bugger all to do with 'de-neutralising' the black, even if thats what the schemes say, we have a convention that it makes sense to stick to regardless of new/old colours

 

[poni]

Yes I get that but I still get call out to "I've added a light" and they have cut a 3 core

I used to love that sort of call out 5mins work, £50 in my pocket!
yes the bare copper is to make easy to strip the cable

 

[binky]

Not only that we now have to space rcbos or equivalent out so long use ones are not together.

So no more nicely arranged boards going from large to small unless you put spacers inbetween.

It's getting crazy

not heard that one before!

 

[mort2376]

Yep. It's like the "I've replaced a light but don't know where the wires now go, or I joined all the reds and all the blacks together and it went bang" type jobs.

5 mins with a test lamp and it's swipe your card here time.

 

[poni]

I thought we used blue because of 3core flex blue was neutral and yellow was half of the green/ yellow

 

[mort2376]

not heard that one before!

Only just starting to come in. Was at the last Napit event. Its to avoid circuits that are high use high current (ev) overheating theirs and neighbouring mcbs/rcbos. As ev chargers are high load over a long period.

Hence why Lewden now have a 39 way board

 

[Andy™]

yea and now I have to £295 for another assessment visit

complain. remind them they are assessing you for compliance with BS7671, not their opinion or what they think it should be