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Discuss What CU? in the Electrical Wiring, Theories and Regulations area at ElectriciansForums.net

T

Thunderpants

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I have been asked to carry out work on a mates new ground floor extension. Putting in a ring main, lighting circuit + external lights. This is all for my initial NAPIT assessment (date to be confirmed) so itsquite a good install to show.

Including with this will be a CU replacement in which his dwelling has 2 rings, 2 lighting circuits, cooker and shower. Bonding and tails need upgrading as well.

I have been told due to the price of RCBO's dropping it is getting just as cheap to buy a basic board and fit each circuit on an individual RCBO. A split load board would also provide protction in this way except a whole bank of circuits would be lost instead of just 1. My last thought is protect sockets, shower and external lights on MCB's via RCBO protection with the other circuts on MCB's.

What are your thoughts? They all have their pro's and cons. I have yet to do any price comparisons.

Thanks TP
 
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A

acat

  • Thread Starter Thread Starter
  • #2
As its for your assessment dont go to complicated as you may end up shooting yourself in the foot with lots of questions. So long as it complies with 17th you cant go wrong.

However having worked out the total amount of circuits buy a CU that will have at least two extra slots for more circuits and explain that it was done to save the customer changing his CU at a later date if he had another circuit added. That tends to go down well as you are thinking about the customers future needs.

Good luck

Chris
 
D

DHES-LTD

  • Thread Starter Thread Starter
  • #3
In CEF proteus 17th edition DB complete with main switch, 2 RCD's and 10 MCB's £65.00 + VAT or proteus RCBO's 48.00 + VAT each so could get expensive doing it that way.
 
G

Guest123

  • Thread Starter Thread Starter
  • #4
My last thought is protect sockets, shower and external lights on MCB's via RCBO protection with the other circuts on MCB's.
Dont forget that under the 17th the other circuits will probably need RCD protection also depending on installation method i.e in a wall at a depth of less than 50mm with no earthed metallic conduit etc.
 
M

MTI

  • Thread Starter Thread Starter
  • #5
all the above are fair coments but id certainly do your periodic first. will you be informing building council etc? part p says you have to report and certify the work within 28 days of completion to napit/elecsa etc. im having this problem at moment and going in for my assessment soon hopefully. currently paying approx 200-250 on every job to get cerified by a pal who i often work for/share work with
 
S

skirby

  • Thread Starter Thread Starter
  • #7
I would count up the number of circuits required and add at least 2 for spares.

Using 17th Ed CU is good with 2 x RCDs and put the lighting circuit and ring main nearest to the CU on RCBOs to help to see the board when tripping occurs.

RCBOs are more expensive but worth it when trying to locate faults if you get an evening call for nuisance tripping on replacement CU jobs.

I have found Wylex to be very easy to work with and reliable for domestic jobs, but a bit short of space in the top right hand corner above the RCBOs (just as most makes).

Good luck.
 

sparks1234

-
Arms
Hager for me, split load board about £50-00, MCB £3-25 each or if you want about £25-00 for consumer unit with main switch and £20-00 per RBCO
 
hi all

mk 17th ed board i normally use, plenty of room at top. offer on at eddies at the mo 10 useable ways c/w 8 mcb's £69.00 +vat. mk rcbo's are about £22 a piece. must admit though i have had a few faulty mcb's lately.
 
M

mags1972

  • Thread Starter Thread Starter
  • #10
hi all

mk 17th ed board i normally use, plenty of room at top. offer on at eddies at the mo 10 useable ways c/w 8 mcb's £69.00 +vat. mk rcbo's are about £22 a piece. must admit though i have had a few faulty mcb's lately.
Hi all, where are you getting these RCBO's for £22+VAT ea, my local Eddies charge £32+VAT ea for Wylex and Hager RCBO's, I thought they were expensive but this is taking the ****!!
Cheers

Ian
 
Last edited by a moderator:

sparks1234

-
Arms
Hi all, where are you getting these RCBO's for £22+VAT ea, my local Eddies charge £32+VAT ea for Wylex and Hager RCBO's, I thought they were expensive but this is taking the p***!!
Cheers

Ian
With the Hager RCBO's make sure you are getting the model for the Consumer unit rather than the 3-phase distribution board, the neutral tail is longer in the dis board model and for some reason Hager have not been giving the discounts out so easily on these.
I deal with a small wholesaler in Welwyn Garden City and City elec in Luton and both are about the same price at £20-00 + VAT
 
hi

eddies were charging £34 each but wf wades started selling the mk rcbos for £21.50 so i had a winge to the eddies rep and he then came back and said the best they could do was £22. but a few months later the local wf wades closed down...must have been because of the rcbo's :D
 

stretchyboy

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Arms
try twisting their arm with a copy of this thread, we have accounts with 6 wholesalers and half of them provide rcbo's from 22-25 quid with the rest between 25-30
 
A

ajelec10

  • Thread Starter Thread Starter
  • #14
if you really squezze the wholesaler you can buy crabtree/wylex rcbo's for under £20! i like crabtree as the bus bar is insulated.
 
M

mags1972

  • Thread Starter Thread Starter
  • #15
Cheers guys I'll try twisting their arms again, they love it when I bring the screwfix book in so they'll love me now, serves em right for chrging too much!! :D
 
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