New consumer unit and part re-wiring.. how do you certify ?

[stillp]

I would expect any EICR to be thorough, but the electrician should be made aware that the house is a repo.

 

[ericmark]

Depending on make the maximum size of MCB varies can be as high as 50 amp but any MCB over 32A will have rather heavy cable and the likely reasons for the very large sizes are:-
Shower Feed
Cooker Feed
Second consumer unit feed (Like garage or Kitchen)
There is very little over 32A.
At 32A Cooker, ring (for sockets), even small shower.
At 20A radial (for sockets)
At 16A immersion heater, oven and where storage heaters are used then they too are often 16A.
At 6A lights.
Sometimes one finds lights on 10A MCB which rings alarm bells as most lights will have something somewhere rated at just 6 amp.

When doing an inspection alarm bells ring when one finds 6mm cables connected to a 40 A MCB and most will start with the consumer unit and look for tell tail signs of work done by some one who does not follow the rules.

With most inspections be it electrical or any other to complete in a short time the normal method is to inspect where you expect to find faults and if not found one assumes the whole to be OK. Once any fault is found then the inspecting goes to next level and one starts to look deeper. Yes checking all is correct way but in real terms if one realises everything is new and well done one does not look as deep as when it looks old with shoddy workmanship.

This will include previous paperwork. When one is presented with all previous readings as one should be and all the readings match with new readings one is reasonable certain all is OK. Find no MCB's marked and no paperwork and the work load is increased and labelling is extra work and some will charge extra for it.

Turning off all power testing all is dead then one at a time returning power and finding what it feeds is time consuming and clearly you don't want to be charged for that time so that is a job which lends it's self to DIY.

But to rent out you clearly want insurance and that includes having the inspections done by some one who is themselves insured should their report have errors. When working on commercial premises it's common to have to show insurance documents before starting which are normally copied and returned. It's all down to shifting the blame when things go wrong.

There was a report a few years back about an electrocution where the tenant had reported there was a problem before moving in, and my first thought was "If you know there is a problem before moving in then why move in?" How ever it was not the tenant the courts blamed.

We do seem to have an unfair system with an open fire should a child be injured we look at tenant for not using a guard or monitoring the child but with just as obvious dangers with electric it's the land lord who is blamed.

So even though I could easy inspect and test my own house if I was going to rent it out I would employ a third party to do the work. Although all faults would be corrected first.

The rules take some interpretation for example any metal part which can be touched should be less than 80 deg C, but clearly the cooker hob would not be much use if it only got to 80 deg C. Some common sense is required but this means some understanding so there is a limit to DIY.

 

[SimonH2]

I was just puzzled as to why there was only one 40AMp MCB

Two simple answers come to mind ...

1) Because whoever did the work determined that only one circuit required a 40A MCB - so only that circuit has a 40A MCB.

2) It looks (from the full board and lack of labels) like it might have been a package - ie buy the fully loaded board which comes with a pre-selected set of MCBs. In practice, the pre-slected set of MCBs will only match the requirements for a tiny number of installs - and normally the installer would remove the ones they don't need. IN this case, it could be that the installer simply left all teh MCBs in even though they are not supplying anything.

A key thing to remember is that there is absolutely no such thing a a standard set of breakers. It may be that in a development of identical properties, there will be a number of properties with all CUs the same, but that's a different matter. The number and rating of breakers will be determined by the requirements of the install - and it's very common to have nothing larger than 32A (or 30A if still using fuses).
A while ago I acquired a second hand CU fully loaded with 6off 16A breakers - nothing smaller, nothing bigger. It had been taken out of a property where it had been the supplies for off-peak storage heaters.