Rewire of upstairs

When notifiable work eg . A new circuit or a new consumer unit is done you have no more than 30 days to notify building control . So in answer to your question yes you can get the upstairs of your house re-wired and the new consumer unit done first . An installation certificate should then be issued for this work along with the building control notification certificate. Then when you rewire the downstairs an installation certificate and building control notification certificate would be issued again for the new circuits added . A registered electrician would be able to easily do all of this in your behalf .

If you are having work that is notifiable for Building control I.E new consumer unit , any new electrical circuits then this would automatically happen through the electricians registration with Napit/NICEIC once the spark finishes the certification. The cost for having work notified twice isn’t massive , unfortunately all sparks have to adhere to the regs and the notification process. I would go ahead and get the work done and signed off and then when you are ready to do the downstairs you will have to get that signed off. You are talking hundreds and not thousands for certification. Once upstairs is finished and the new consumer unit installed , the additional work downstairs would be a separate certification and upstairs wouldn’t be done twice unless it shares a ring or other circuit with the new work to be done. So the answer is yes you can do upstairs and a new C/U and yes downstairs will need an additional certificate once it’s finished. But it’s not a massive expense to be signed off.

When you get quotations for the upstairs work, ensure you get a Part P registered electrician, someone who is a member of one of the schemes. You can search online for registered electricians. The electrician will automatically include in his price for testing, certification and Part P compliance for all of the new work no additional costs to be added for those items. When you get the second stage quotations for the downstairs same applies. It is two completely separate jobs. Non-registered electricians have to apply separately to Building Control to have their work inspected and tested. Those costs will be in addition to his price. It is much easier to employ a registered electrician and much less hassle. Just ask to see their membership details and verify them online. It may be possible to use the same electrician for both jobs if you are happy with him when he's completed the first. In fact it would be preferable to do that to avoid potential petty quibbling about the other electricians work which often happens.

Basically Yes. You can have the rewiring done first and the installer can leave circuits and cables ready to be used for the extension later on. You'll need lights, sockets, cooker etc. Your electrician should furnish you with two certificates. One with the test results of the circuits and another building compliance certificate to demonstrate the work is lodged with building control. You need an electrician that is registered on a competent persons scheme like NAPIT or ELECSA to do the work and issue certificates. DO NOT accept any generic paper certificates. Also I would dispute quite vigorously Houston Electricals assertion that issuing certificates or 'signing off' work is hundreds not thousands? If an electrician is doing electrical work they are obliged under law to certify the work, it's not 'extra'. That's rogue trader practice whereby the customer is effectively blackmailed at the final hurdle to hand over extra for certification. Any electrician should be pulled up on this practice. All certification is inherently part and parcel of installation, not separate.