Mk II: How does my DIY effort at a consumer unit look?

[rcd1976]

Few days back, I posted this:
//www.diynot.com/forums/electrics/how-does-my-diy-effort-at-a-consumer-unit-look.311484

Following on from some helpful comments I've had another go:
- Biggest change was putting the earthing banjo on the SWA gland. Note it does have the black plastic shroud on too, I just removed it temporarily to show the SWA termination.
- I rerouted the incoming earth which made life a lot easier, and a bit neater
- Couldn't get less than 100m of sleeving so I've just left the mix of old and new colours, but I've put the sticker on the cover warning people
- I've left the 20A MCB dedicated 'ring' (two connections of 2.5sqmm T&E) for now, even though people thought it was odd, as it just seems silly to take it out and put the extra strain on just one cable.
- Incoming is definitely three 25sqmm incoming cores, in SWA.

Will probably get it checked by Building Control electricians at the end of the week. Anyone want to shoot me down before then?

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• rcd1976
• 12 Feb 2012
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• rcd1976
• 12 Feb 2012
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• rcd1976
• 12 Feb 2012
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• rcd1976
• 12 Feb 2012
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• rcd1976
• 12 Feb 2012
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[JohnW2]

- Couldn't get less than 100m of sleeving so I've just left the mix of old and new colours, but I've put the sticker on the cover warning people

I don't think this was discussed very much in the previous thread ... because it's 'old colours SWA', your incoming conductors are red for L and blue for N. 1-phase-wise, that is a mixture of old and new colours in the same 'pair', and I'm not at all sure that the 'different version' sticker really covers that sorts of 'mixed'. I would personally think that either the blue one should be sleeved (or marked with tape) black, or the red one sleeved (or taped) brown, so at least both conductors of 'the pair' correspond to the same (old or new) colour system. Also, the incoming earth (yellow of SWA) should really be sleeved G/Y (or, again, G/Y tape would do). ... but all that's just my opinion; others may disagree.

Kind Regards, John.

 

[securespark]

Nope. Concur with John. Have old & new colours in the install by all means, but don't mix colours within the same cable.

 

[rcd1976]

because it's 'old colours SWA', your incoming conductors are red for L and blue for N. 1-phase-wise, that is a mixture of old and new colours in the same 'pair', and I'm not at all sure that the 'different version' sticker really covers that sorts of 'mixed'. I would personally think that either the blue one should be sleeved (or marked with tape) black, or the red one sleeved (or taped) brown, so at least both conductors of 'the pair' correspond to the same (old or new) colour system. Also, the incoming earth (yellow of SWA) should really be sleeved G/Y (or, again, G/Y tape would do). ... but all that's just my opinion; others may disagree.

Kind Regards, John.

Thanks that's really clear. I'll try a couple more places for some sleeving, otherwise I'll just use tape. Shouldn't be a big job to put them on with the way the incoming tails run now. (unlike fitting the banjo on the SWA, which meant pulling everything out and starting again...)

 

[PrenticeBoyofDerry]

Why no RCD protection on cooker ?
I take it this is the cooker circuit:

I've left the 20A MCB dedicated 'ring' (two connections of 2.5sqmm T&E) for now, even though people thought it was odd, as it just seems silly to take it out and put the extra strain on just one cable.

Do the two lengths only supply cooker and nothing else?

 

[riveralt]

- Incoming is definitely three 25sqmm incoming cores, in SWA.

Are you sure about that. The three cores look about the same size as the internal cabling provided by the consumer unit manufacturer and they are normally 16mm2.
According to Eland cables cataglogue the external diameter of a 3 core 25mm2 SWA cable is nominally 25.5mm . Its 21.6mm for the 16mm2.
When clipped direct the current carrying capacity of SWA 25mm2 cable is 124Amps and for 16mm2 94Amps.
Unfortunately counting the number of strands doesn't help because both 16 and 25mm2 cores have the same number of strands, 6 or 7,
so the diameter measurement is only measurement available without measuring and calculating the resistance value of each core.

One other thing, some testers may raise the issue of ranking your mcbs/rcbo in power order with the highest power nearest to the switch.
And make sure the designated earth cable, which needs to be green/yellow by the way (70% of one colour) does not foul the buzz bar.

 

[crystal ball]

With regard to highest rated MCBs nearest the main switch, is this a manufacturers recommendation, surely the busbar is rated at 100amps or more so why would it matter, if I was picked up on that I would want to see the relavent reg/ruling

 

[EFLImpudence]

Didn't a recent thread deduce that, while everyone does it that way, no one could actually think of a reason.

 

[Alarm]

Older CU`s made you fit them that way with the way the fuse holders were made. So a continuation I assume.

 

[sparkwright]

Gland looks good.

I admire the effort you're putting into this, but you still didn't put the larger circuits nearest the main switch!!!

 

[sparkwright]

You could reduce all that copper showing on neutral number three, bugs me.

And just a small bit of green and yellow tape on the yellow earth of the SWA.

 

[EFLImpudence]

Older CU`s made you fit them that way with the way the fuse holders were made. So a continuation I assume.

Oh yes, agreed.

Perhaps I should have said - no one could think of a reason against not doing so in a modern CU.
E.g. the one in this thread.

 

[mattylad]

You could reduce all that copper showing on neutral number three, bugs me.

I was just about to say the same - too much copper showing - unscrew & push further in.

 

[JohnW2]

- Incoming is definitely three 25sqmm incoming cores, in SWA.

Are you sure about that. The three cores look about the same size as the internal cabling provided by the consumer unit manufacturer and they are normally 16mm2.

Are you sure about that. If one magifies the picture, the SWA looks (to me) apprerciably fatter than the internal N cable:

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• JohnW2
• 12 Feb 2012
• 1

Kind Regards, John.

 

[crystal ball]

Older CU`s made you fit them that way with the way the fuse holders were made. So a continuation I assume.

I can't remember that, I've ripped out plenty of old CUs and never noticed any keyways etc, some wylex CUs had a seperate way for larger fuses but that was on the other side of the switch I recall