Changing a old board for new one

[smthdeedog]

hi guys its me again, well this should be straight forward i guess. iam going to take the old board off three bed room house.which has the
old style fuse's,rewire.two red,one white,and one yellow. so basically
tape and number each wire from the fuse it came from.and put back
everthing i took off the old board on to the new board is that right
don't think i can mass that up come on?

 

[mst]

Depends if your a DIYer

 

[plugwash]

its not as easy as you think:

firstly there are RCD arrangements to consider, general domestic practice is to use a split load board with lights on the NON-RCD side and sockets, showers on the RCD side, other stuff may be located on either side and there are pros and cons to both arrangements. Outside wiring should have RCD protection somewhere but its best if its a seperate RCD.

secondly there is the fact that if you put a circuits onto the RCD side that were previously not RCD protected there is a good chance you will expose hidden faults that will need to be corrected.

thirdly there is the issue of isolating the incoming tails, often this can only be done by pulling the service fuse which is only supposed to be pulled by the DNO. Some DNOs are reluctant to do this for diyers. Many people pull it themselves but this is illegal and can be dangerous (particularlly if the service fuse is old or in bad condition)

fourthly the circuits should really be tested as you are changing the characteristics of thier fault protection (though honestly they are far more likely to be safe on modern breakers than on rewirable fuses)

fithly some cables may not reach thier locations within the new CU, theese will need to be extended (by through-crips, terminal block or soldering and heatshrinking) inside the new CU.

finally you should note that this *is* notifiable under part P

 

[securespark]

Well, you asked!

Yes, you can mess up big style!

You need calibrated 16th Ed. test equipment to be sure that everything you are reconnecting is 100%. By this I mean you need to make sure Ze, Zs at the destination of each circuit is sound. You need to check IR readings, test RCD's Do R1's & R2's, check ring continuity, etc etc...

You need to fit the correct CU arrangement depending upon supply type.
You have to fit main equipotential bonding to all services and you may as well update supplementary bonding in the bathroom at the same time.

That should keep you thinking for a bit!

 

[DESL]

this should be straight forward i guess. iam going to take the old board off three bed room house.which has the
old style fuse's,rewire.

If only!!!!!

 

[securespark]

We've frightened SDD off...

 

[RF Lighting]

Lets hope we scared him off the idea of replacing his own cu, not from asking questions.

If you have to come on here asking simple questions, then IMO you are not competent to replace a CU.

I get the feeling the OP will replace it himself regardless, but lets just hope he doesn't kill him self either in the process or as a result of.

There is often much more to replacing a mains than simply moving wires form the old board to the new one, and it really pis*es me off that people do not understand this, regardless of how many times they are told by 'experts'

I wouldn't attempt a heart transplant.
I don't know how to.
To an experienced surgeon though, I'm sure its a simple case of disconnect all the tubes from the old heart and reconnect them to the new one.
Get it wrong and someone dies.

[/rant]

 

[DESL]

I was asked by a mate for a price of a new CU supply and fit

He said I must be joking that much just to swap some wires over I'll do it myself can't be that difficult!!

 

[Pensdown]

I must be getting soft because after seeing the Leeds post I'm beginning to agree that a CU change is not a DIY project

 

[DESL]

I'm beginning to agree that a CU change is not a DIY project

Never has been unless you have the appropriate test kit and knowledge!!

 

[Pensdown]

DESL, what's the difference between the average domestic sparks and a competent DIYer?

 

[plugwash]

I wouldn't attempt a heart transplant.
I don't know how to.
To an experienced surgeon though, I'm sure its a simple case of disconnect all the tubes from the old heart and reconnect them to the new one.
Get it wrong and someone dies.

I think thats a rather exaggerated and unfair comparision.

unless the person replacing a CU is really stupid (remember the pictures on here a while back of the CU with the cuircuit cables in the same end of the breakers as the bussbar) then replacing an old fusewire CU is very unlikely to make the installation less safe than it was before.

 

[DESL]

what's the difference between the average domestic sparks and a competent DIYer?

About £600 of test kit and an understanding of Inspection & Testing
A good knowledge of BS7671
Public Liability & Professional Indemmnity Insurance

I could go on....

I used to be a competent DIYer & I thought I knew it all being a qualified Electrical Engineer then redundancy made me take up my current business. Oh boy have I learned a lot since then including going back to college and getting the relavent quals

 

[smthdeedog]

guys rome wasnt built in a day.how else am i to get experience, how did the expert electrician get to were he is today! not saying to his self i better
not try that i'll leave it to the expert. I am not saying you guys are wrong in what you are tell me.otherwise i wouldn't come in to this forum all i'am asking you guys is to help me through it.Please there are two rings mains,one fuse for lighting.and a fuse that is yellow which might be for the boiler.what cu would be good for this house 5way or 8way 12way? the house is paid for. so up grading the cu will bring the property price up. thanks again and hope you guys can help me.

 

[securespark]

how did the expert electrician get to were he is today!

By learning his trade on the tools with a qualified guy, and by going to college to learn the theory.

That's how.