1st 17th ed board

[Chri5]

Here's a couple of pictures of my latest work

1st 17th board installation-11 circuits and a few spares..

No problems other than planning the offset for RCD1 and RCD2 circuit designation, trying to balance the potential load across both RCD's and making sure there was an RCBO for the smoke detection on the direct rail.

Critic invited, would you have done anything different?

17th ed with excel labels

• Chri5
• 12 Jun 2008
• 2

cover off

• Chri5
• 12 Jun 2008
• 4

isolated at dno switch

 

[Chri5]

What I would add is that on RCD 1x and 5x tests the 17th edition boards do highlight 'lazy' rcds.

All tests well inside the guidelines, but RCD for circuits B was 50% slower than RCD for circuits C.

If only the makers kept the tolerances a bit closer- the test results looked odd when RCB 'B' was circa average 40ms and the RCB 'C' was averaging about 25ms.

I did the an4l thing and swapping some circuits around and it was the lazy RCD rather than any installation issues.

 

[dannyboi2003]

Hi Chri5,

Very neat job mate, one question though.... Why fit MCB's in the spare ways and not blanks? Do you plan to use them, if not then just seems a bit pointless.

All the best
Dan

 

[Steve]

To add to dannyboi's comment, the two MCBs on the non-RCD rail are badly placed, since a householder may connect a circuit to these, not knowing the regs regarding RCD protection. Would definitely have got some blanks. Are there any circuits that you could connect to these, within the regs??

 

[sparkybird]

Steve

Yes - in domestic, anything that is not a socket outlet and the supply cables are not concealed (eg run surface in trunking/conduit/clipped) or run concealed in earthed metallic conduit.

I am now using one of these ways for the 'fuseboard' cupboard light where possible - clipped or run in trunking - means that even if both rcd's go, the customer can still see the fuse board!

SB

 

[Chri5]

Customer is always right

They asked for the spares to be populated with MCB's left over from previous works rather than blanks.

I agree that having 2 spare MCB's populating the direct side is a bit naughty, but the concern was that some earth leaky equipment may pop the RCD sides. Fridge, freezer, oven and computer are all older equipment.

The whole site has >50mm depth cable runs due to building controls requirement for 50mm kingspan and 32mm foam back plaster boards on all external walls. All non lighting cabling has been run via the floor voids and conduit up walls (to keep away from the insulation de-rating issues).

If you notice there's quite a few 20A rings (3 of 5) because client wanted them that way.

One thing that still makes the job look good, is 15 minutes on MS excel making decent, clear labels for the CU designation- well I think so!

I'm back there in a few weeks and if there's no issue with eath leaky equipment I'll take out the spare MCB's on the direct since I agree with the comments.

 

[dannyboi2003]

Ahh those type of customers are always the best

20amp rings - utterly pointless

Spare mcb's in a new installation are not likely to ever be needed and as wylex is a big brand spares are likely to be available for the life of the CU anyway. Also you have fitted higher rated mcb's after lower rated ones, i always thought rule of thumb was to work upwards from the main switch/rcd so the spare mcb's just make it look untidy. I'd pull them all out and fit blanks.

At the end of the day if the customer wants to waste money then thats their concern not mine but i certainly would not have cabled ring circuits and fitted them with a 20amp mcb regardless of what the customer wants. You should be designing the circuit not the customer.

Anyway thats my 2 pennies worth, not having a go in any way Chri5 as its a neat and tidy job, i just hate it when people (the customer in this case) stick their nose in where its not needed!

All the best
Dan

 

[Spark123]

What size are the tails?

 

[Chri5]

16mm Earth and 25mm L/N

 

[plugwash]

Spare mcb's in a new installation are not likely to ever be needed and as wylex is a big brand spares are likely to be available for the life of the CU anyway.

IIRC wylex have a nasty habbit of slightly changing the dimensions of thier breakers without changing the model number sometimes requiring the busbar to be bent to get different generations of breaker in the same board.

 

[Sherbertlion]

If you notice there's quite a few 20A rings (3 of 5) because client wanted them that way.

Why not just wire as 20A radials and save yourself a bit of cable!

 

[GaryMo]

What size are the tails?

I thought that, they look more like 16mm L&N (compare them to the main earthing conductor) but as Chris pointed out they're actually 25mm.

Chris, why use the 'wiring colours to two versions' sticker then handwrite 'harmonised' on it?
If all cabling is of harmonised colours then no sticker is needed. It looks a little untidy.

 

[RF Lighting]

I use these:

View media item 1853

 

[Sherbertlion]

I hope you haven't got too many of those labels left!

 

[RF Lighting]

I was just thinking that as I posted that pic.

Wonder how long until they are being sold off cheap in the wholesalers?