Swapping over my consumer unit this weekend...

MisterE · 13 May 2010

Alright everyone??

Yeah, yeah, I'm good ta...

Right then - I want to swap out an old consumer unit with a newer one, and bring it up to date with the current regulations... I've picked up one of these badboys from screwfix (http://www.screwfix.com/prods/32831?cm_sp=CatBanners-_-position1-_-ElectricalSupplys&ts=53807) and will probably rip the old one out over the weekend.

What I'd like to know is can I just cut all the wires out of the old box, and plug them into the new one? Should they all match up in the same place?? Pretty sure I can, but a bit worried about shocking myself again. If I turn the main trip switch off, I should be safe yeah?

Anything else I should look to replace while I'm doing this work - power sockets, light switches etc? Need to order stuff by this evening to ensure getting stuff for the weekend..

Thanks guys.

bongos · 13 May 2010

Afternoon MisterE.

There's a mass of things to consider. Too many for me to be bothered to list here!

You will require an EFLI meter to check your earth loop readings are withing spec. An insulation resistance and also an RCD tester will be required for this install to make sure there are no problems and that the cables you are reconnecting are upto spec. I apologise if you already have these.

The Wylex board you link to looks just fine for the job.

One other minor point too //www.diynot.com/wiki/electrics:part p.

Monkeh · 13 May 2010

MisterE said:
What I'd like to know is can I just cut all the wires out of the old box, and plug them into the new one? Should they all match up in the same place??

No, the layout is likely to be very different. You'll have to tag each circuit as you disconnect them, and may need to extend them.

Pretty sure I can, but a bit worried about shocking myself again.

Then perhaps you should leave the work to a competant electrician?

If I turn the main trip switch off, I should be safe yeah?

Define 'main trip switch'. If you mean the isolator on the board, no. The tails will still be live.

MisterE · 13 May 2010

bongos said:
Afternoon MisterE.

There's a mass of things to consider. Too many for me to be bothered to list here!

You will require an EFLI meter to check your earth loop readings are withing spec. An insulation resistance and also an RCD tester will be required for this install to make sure there are no problems and that the cables you are reconnecting are upto spec. I apologise if you already have these.

The Wylex board you link to looks just fine for the job.

One other minor point too //www.diynot.com/wiki/electrics:part p.

Cheers for the quick reply mate - it's much appreciated.

Do I definitely need them tools? Don't have them at the moment you see... Everything works fine at the moment - no problems with the insulation & am pretty sure that my ELFI must therefore be within acceptable limits.

Never done this before though, so if I have to get more tools I'll buy them - bit pricey though, but I guess they'll pay for themselves after doing this a few times!

MisterE · 13 May 2010

Cheers for your help.

The consumer unit I've got already has everything separated into 'zones' - downstairs ring, upstairs ring, shower, lights, kitchen etc... so I can just move them over to the new CU, right?

I was going to get a sparky in, but can get the bits cheaper from screwfix (until I saw matey's reply above about the tools, that is!) and do it myself for a fraction of the cost - will be a good learning experience anyway, for when I need to do it again.

Cheers.

Monkeh · 13 May 2010

MisterE said:
The consumer unit I've got already has everything separated into 'zones' - downstairs ring, upstairs ring, shower, lights, kitchen etc... so I can just move them over to the new CU, right?

You're assuming the preconfigured CU you've bought matches exactly your existing wiring. This is rarely the case..

I was going to get a sparky in, but can get the bits cheaper from screwfix (until I saw matey's reply above about the tools, that is!) and do it myself for a fraction of the cost - will be a good learning experience anyway, for when I need to do it again.

You should not need to do it again. You most likely do not need to do it now.. The most likely learning experience from attempting this yourself is learning how well your flesh cooks when you short a 100A supply.

Steve · 13 May 2010

MisterE said:
Do I definitely need them tools? Don't have them at the moment you see... Everything works fine at the moment - no problems with the insulation & am pretty sure that my ELFI must therefore be within acceptable limits.

This is exactly why consumer units are changed by electricians, and not DIYers.

"no problems with the insulation" - How do you know? Have you tested it?
"pretty sure that my ELFI must therefore..." How do you know? Have you tested it?

That preconfigured board may not suit your needs. What will you do if you need another 32A MCB? What will you do if you connect a circuit and it trips the RCD, because it wasnt on an RCD before and therefore you didnt know it was faulty? How do you intend to shut of the supply to the CU? What are you doing to comply with Part P?

Theres much more to this than you think - please get an electrician in. He may be able to use the board you bought - but he might not like the brand and want to fit something else. He might decide it doesn't suit your system. He might be right.

MisterE · 13 May 2010

Monkeh said:
MisterE said:

The consumer unit I've got already has everything separated into 'zones' - downstairs ring, upstairs ring, shower, lights, kitchen etc... so I can just move them over to the new CU, right?

Click to expand...

You're assuming the preconfigured CU you've bought matches exactly your existing wiring. This is rarely the case..

Ok, see what you mean - sort of thing you won't know till you try though I suppose...

I was going to get a sparky in, but can get the bits cheaper from screwfix (until I saw matey's reply above about the tools, that is!) and do it myself for a fraction of the cost - will be a good learning experience anyway, for when I need to do it again.

Click to expand...

You should not need to do it again. You most likely do not need to do it now..

Definately needs doing - old one is all broken and covered in yellow paint... we're redoing the kitchen and I want to make a bit of a feature of this as its right in the middle of the room and can't really box it in.

The most likely learning experience from attempting this yourself is learning how well your flesh cooks when you short a 100A supply.

Going to be extra careful doing this, don't worry about that - will turn everything off first... last time I got zapped hurt like hell!

Monkeh · 13 May 2010

MisterE said:
Going to be extra careful doing this, don't worry about that - will turn everything off first... last time I got zapped hurt like hell!

How are you going to turn it off?

You really, really need to get an electrician in. You do not understand the depths of what you're dealing with.

MisterE · 13 May 2010

It definately seems more involved than I thought - will get a sparky in if I get stuck... don't want to be left with anything dangerous, but if it looks like a simple swap, then I should be ok with that.

Thanks for all your help guys - love this site...

Steve · 13 May 2010

Sparkies charge more for emergency callouts at weekends, than a pre-booked half day slot.

holmslaw · 13 May 2010

westeleven · 13 May 2010

Mister E if against all the well meant advice you attempt this yourself then do please clock in to tell us you are safe as if you are never heard of again we will be sure you 'got zapped Real Good'

Taylortwocities · 13 May 2010

You have a whole host of things to test and check before you start and during the change over.:

Have you notified the local authority that you will do this work and paid their fee (at least 48 hours before starting)?

What is the type of supply? Is the earthing and main bonding conductors up to the new requirements?
Is there an earth electrode?
Are the rings really rings? What is the R1+R2 value for each?
Have you tested the insulation resistance of each circuit?
Are the test values within limits?
Are there any SELV devices?
Do the two RCDs in your new circuit board operate within acceptable limits?
Have you tested that the Zs for each circuit is within limits?
Do you have BS7671 installation certificates to complete with all of your test results so that the local authority can check your results and give you a completion certificate.

Note, some of the above are LEGAL REQUIREMENTS.

If you do not have the correct paperwork evidence then you will have real problems when you come to sell the property as the buyers and their solicitors will want to see it.

bongos · 13 May 2010

MisterE said:
It definately seems more involved than I thought - will get a sparky in if I get stuck... don't want to be left with anything dangerous, but if it looks like a simple swap, then I should be ok with that.

There is alot involved and unfortuantely if you don't know what you're looking for it could end up being an absolute nightmare.

Definitely get a spark in. If you were going to change yours legitimately and notify it to the LABC then you will probably find it cheaper using a spark who can self certify and save all those man hours scratching your head over nusiance RCD trips!

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Swapping over my consumer unit this weekend...

holmslaw

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