This is probably not what you want to hear but it is my professional advice.

Get you installation properly designed by a professional electrical engineer competent in electrical installation design. Then get the installation re-wired by a professional competent electrician to meet the design.

This is not a job for  a DIYer, however enthusiastic, who has gleaned some knowledge  from the internet.

JP

I did wonder why somebody who seems to be embarking on a complete installation was asking what amounts to basic questions. However, it is apparent from the ethernet discussion that wpqs has given some considerable thought to the project.

Having wired my step-daughter's self build and seen the effort which they have put in, I can understand why wpqs might want to do the work personally. I suppose that a reasonably bright person could, for example, terminate SWA after watching videos on youtube, but that is not the same as learning at college and on the job. Equally well, I dare say that I could put in new central heating in my house (save for the gas pipes), but I wouldn't know how to test it let alone having the correct equipment.

A friend is having an extension built. There is a 3-phase main to the corner of the house where it becomes a single phase service cable. Matey wants to extend the 3-phase supply to the garage, and then bring it back in the same trench to the house. The walls are up and there is ducting for the electrical supply. However, what has not been considered is whether there is room in the duct for two cables.

That is simple an example where proper design in advance saves a lot of bother.

The following applies to this thread as well as another about data comm / alarm wiring.

Just to be clear, I'm not intending to do any of the rewiring work myself with the possibly exception of connecting the CAT 6 cable and that's only because in a previous project I paid a lot of money to a 'professional' and then had to redo the work myself. I will be employing a fully qualified electrician. I am also employing a qualified ME engineer to provide design and oversight.

What I am trying to do is avoid paying this engineer for producing hundreds of pages of documentation that nobody will read and demanding compliance with standards intended for large office blocks and hospitals which have very different needs to my own small domestic house. I also want to avoid having a specification that only a large electrical contractor can undertake. It is for this reason that I want to understand what the standards require so I can get the job packaged in way an average electrician can understand and also create a relatively safe home - relative, because absolute safety against all eventualities can never be achieved imho.

The aim is to spend money on buying the best quality components I can afford and employing an electrician who will do quality job rather than generating a mountain of paper. Unfortunately finding an ME engineer who is a problem solver rather than a problem creator is difficult. This may be because there is far more money in creating problems.

Although I appreciate that it is difficult finding a good tradesman, I foresee difficulties if you do not agree with what is proposed. ME = "mechanical engineer"?

Although I appreciate that it is difficult finding a good tradesman, I foresee difficulties if you do not agree with what is proposed. ME = "mechanical engineer"?