Too many circuits?

[RF Lighting]

Is that a neutral tail made up of loads of individually twisted cores?

The board is fed with a 25mm² split concentric cable.

If you’re not familiar with it, it’s a 25mm² live conductor surrounded by 11 insulated wires which equal 25mm² to form the neutral conductor, and 4 uninsulated wires which equal 16mm² to form the CPC.

 

[plugwash]

I'm personally no great fan of (2.5mm²) 20A radial sockets circuits, since 20A is theoretically not enough for more than just one 'fully loaded' double socket - but (4mm²) 32A radial sockets circuits seem fine.

One issue with 4mm² 32A radials is that they are pretty closer to the line on cable rating. So a slightly more adverse installation method can easily push you up to 6mm² which in turn means most sockets won't have the terminal capacity to take 3 conductors.

 

[JohnW2]

One issue with 4mm² 32A radials is that they are pretty closer to the line on cable rating. So a slightly more adverse installation method can easily push you up to 6mm² which in turn means most sockets won't have the terminal capacity to take 3 conductors.

Yes, strictly speaking that is all true, and I was obviously talking about the situation in which a 4mm² 32A radial was 'possible' (compliant). I would personally not consider a 6mm² sockets circuit so, if 4mm²/32A were not possible, I might consider 4mm²/25A (if an MCB were available) or else would probably revert to a 2.5mm² ring, with 1 or 2 x 20A radials as my least-favoured option.

However, when 4mm²/32A is possible, then I would favour that over a 2.5mm²/20A radial, for the reasons I previously mentioned. The designer is expected, amongst other things, to minimise the 'likelihood' of the load on a circuit exceeding its 'rating' (cable and OPD) and, with a circuit consisting of multiple "13A" outlets, that likelihood undoubtedly would be less on a 20A circuit than on a 32A one.

Kind Regards, John

 

[Taylortwocities]

The question with these upstart importers/distributors (i'm fairly convinced they aren't real manufacturers) is are they doing their due diligance to ensure their products are actually compliant and are they going to stick around and support their customers if/when bad product slips through.

All good stuff, it’s important to be able to add to the CU in later years, so a reliable substantial manufacturer would appear to be the best thing to do.
When I started out, the CU manufacturers that I tended to use were big, long established names: MK and GE.
Both are no longer in the CU business.

 

[veedee]

Here’s the last 4 bedroom house I rewired.

View attachment 212139

That's a very tidy job! Absolutely gorgeous

Ultra cheap non-compliant junk.



That's because it's ultra cheap non-compliant junk.
Obsolete before it's even installed.

What 10 way consumer with RCBO would you guys recommend?

I want to do a decent job, but not break the bank

 

[veedee]

OOI If you're rewiring are you only considering final finals? Would radials be a consideration?

I will do a radial for the loft

I will also consider doing a radial elsewhere (after a bit more thought/research) as there appears to be a few posts questioning wherher a ring is required in all the places I'm proposing

Fuse box are good value.
£10 rcbo.

Look at consumer unit world.

Is Hager a good brand?

https://www.consumerunitworld.co.uk/hager-vml110-10-way-rcbo-consumer-unit-1796-p.asp

Would this CU fitted with RCBOs be a decent job?

 

[Taylortwocities]

Hager are a good brand, in my opinion, and my CU of choice. But you won’t get quality at a low price.
Hager RCBOs are £20ish plus vat.
Fusebox RCBOs are half that price.

Which is your priority?

 

[ericmark]

With firms like MK dropping there consumer units, going for well established names is clearly no good, so the question is Wylex two RCD or Fusebox all RCBO at very little more than Wylex, seems to me clear go for all RCBO, as to Wylex all RCBO to FuseBox all RCBO well then not so easy, the more expensive makes only do type A you can't buy type AC even if you wanted, and also the more expensive makes offer two pole switching, so if on a TT supply there may well be a case for the more expensive makes. But £80 to £180 to go all RCBO one can see the gain, but looking at Hager.
Consumer unit £88.96 ex vat 13 way with surge protection unit.
RCBO £35.26 ex vat
Total £547.34 ex vat can't see point in working out vat, as I know I got whole lot, cable, box, 14 RCBO's SPU and external isolator with box for under £250 including vat. Looking at £60 v £80 for FuseBox v Hager OK go for Hager but at an extra £300 to have a well known make, then sorry FuseBox most times unless some thing special like double pole switching required.

Of course with double pole switching with RCBO's that does mean the RCBO isolates, where single pole you should use main isolator, but the gain double pole to single pole is so little can't see worth £300 unless TT.

 

[imroberts]

The board is fed with a 25mm² split concentric cable.

If you’re not familiar with it, it’s a 25mm² live conductor surrounded by 11 insulated wires which equal 25mm² to form the neutral conductor, and 4 uninsulated wires which equal 16mm² to form the CPC.

View attachment 212205

Definitely not familiar with it

Is that a similar kind of cable to the DNO feed that comes into the home? In what scenarios would it be used to feed a consumer unit rather than a set of "standard" tails?

 

[SUNRAY]

Ultra cheap non-compliant junk.


That's because it's ultra cheap non-compliant junk.
Obsolete before it's even installed.

How are they non compliant?

 

[JohnW2]

.... and also the more expensive makes offer two pole switching, so if on a TT supply there may well be a case for the more expensive makes. .... but at an extra £300 to have a well known make, then sorry FuseBox most times unless some thing special like double pole switching required. ..... Of course with double pole switching with RCBO's that does mean the RCBO isolates, where single pole you should use main isolator, but the gain double pole to single pole is so little can't see worth £300 unless TT.

Do a significant number of people (I suppose there have to be some ) really use DP MCBs and RCBOs in TT installations? I certainly don't in my house.

Unless I'm missing something, there is no requirement to be able to isolate an individual final circuit (so, as you say, true 'isolation' would require use of a main switch if the OPDs were SP). In any event, let's face it, a CU full of fuses (rather than MCBs/RCBOs) is still theoretically acceptable, and DP fusing is very much forbidden!

More generally, I'm not sure that I necessarily agree with the 'logic' behind the reg's view that, when isolation is required, it should be DP for TT but can be SP for TN-S (SP for TN-C-S is probably OK, provided main bonding is present and satisfactory) ... but that's a different matter!

Kind Regards, John

 

[flameport]

How are they non compliant?

Supplied with 63A RCDs, which are useless unless the installation happens to have a 60A or less main fuse, or the MCBs are configured to have less than 63A of capacity on each one - doing that using the supplied MCBs is impossible.

RCDs are type AC, useless for the vast majority of modern equipment, not the type specified for use by manufacturers of various electrical appliances, totally unsuitable for connecting solar, electric vehicles or battery storage to.

As supplied it's 5 MCBs per RCD, which gives you less than 2mA of residual current per circuit - with modern installations, next to impossible to achieve.

Doesn't contain any surge protection, and has no space for any either.

 

[flameport]

What 10 way consumer with RCBO would you guys recommend?

Electrium (Wylex/Crabtree), Hager, or Schneider.

 

[SUNRAY]

Supplied with 63A RCDs, which are useless unless the installation happens to have a 60A or less main fuse, or the MCBs are configured to have less than 63A of capacity on each one - doing that using the supplied MCBs is impossible.

RCDs are type AC, useless for the vast majority of modern equipment, not the type specified for use by manufacturers of various electrical appliances, totally unsuitable for connecting solar, electric vehicles or battery storage to.

As supplied it's 5 MCBs per RCD, which gives you less than 2mA of residual current per circuit - with modern installations, next to impossible to achieve.

Doesn't contain any surge protection, and has no space for any either.

Sadly much of that can be thrown back at most CU manufacturers, at least 2 of your objections are not a compliance issue.

 

[JohnW2]

• Supplied with 63A RCDs, which are useless unless the installation happens to have a 60A or less main fuse, or the MCBs are configured to have less than 63A of capacity on each one - doing that using the supplied MCBs is impossible.
• RCDs are type AC, useless for the vast majority of modern equipment, not the type specified for use by manufacturers of various electrical appliances, totally unsuitable for connecting solar, electric vehicles or battery storage to.
• As supplied it's 5 MCBs per RCD, which gives you less than 2mA of residual current per circuit - with modern installations, next to impossible to achieve.
• Doesn't contain any surge protection, and has no space for any either.

As has been observed before, it's interesting how thinking changes over time, even though electrical principles don't (and the nature of loads on electrical installations change only gradually and fairly slowly).

Many/most/all of the characteristics to which you refer must apply to a high proportion of (the countless millions of) in-service domestic CUs, and it hasn't taken a lot of time for 'the norm' (maybe even 'state-of-the-art' in some cases) to have turned into 'non-compliant junk'.

Your view (interpretation of the regs) appears to be that CUs with RCDs+MCBs (rather than all RCBOs) and/or with Type AC RCDs/RCBOs are necessarily all 'non-compliant' and also, by implication, that a CU with a "100A" main switch is non-compliant if the total of the OPDs it contains is >100A (which will very commonly be the case). Do you really believe that the the regs really intend that those things (particularly the first two) must be regarded as 'non-compliant' - and, if you do, should the regs not explicitly say that such things are 'not allowed'?

Kind Regards, John