Both my son and I started with other trades and professions, I started as a vehicle mechanic and bridge builder, my so went to university to study maths. In both cases the transition was slow, I moved to auto electrician and went to collage and got my final certificate as an auto electrician while still in my apprenticeship so electrician appears on the deeds. He worked as an electricians mate, then as alarm engineer, and like me also a radio ham and took the RAE exam. Plus taking the C&G 2381, 2391, 2377, and 2382 exams which are 6 and 12 week night class courses when I took them.
Again in both cases we had family in the trade, so some one to ask questions when required, in fact for a time my son worked for me. So I clearly trained him as well as I could.
My move from Auto Electrics to Mains was in around 1978, I had been trained in traffic light repair, and SLD Pumps considered easier to train me to repair pumps than a pump electrician to repair traffic lights, so I went to Leeds for a crash 2 week course on how to repair pumps. It was only pumps at that point any other electrics I was not taught.
1980 I went to Algeria as a Plant Electrician, which was my apprentice trade. However as the only man with any electrical knowledge on site I had to learn quickly how to repair other items, most important was the freezers, size of a shipping container these were ²the most important things on site, I could not re-gas, but I did everything but that, when the refrigeration guy arrived all he had to do was re-gas. No one was interested in regulations.
I flitted between auto and mains, again when working on the Falklands and became full time main electrical working on the building of Sizewell 'B' power station. Did drop back to kind of working auto on the Seven Bridge job working on the 200 ton straddle carrier which was a mixture of both. After that all main work mainly industrial, including working as the site electrical engineer and did in the end get my degree in electrical and electronic engineering. I did a little house bashing, but only when nothing else on offer.
My son moved from alarm engineer to house bashing, then went self employed, then got his big brake, and got a job in a glass works as electrician, they allowed him day release and he too now has level 5 qualifications and has moved up the scale. He found it easier than me, as he had the maths back ground. I would say the maths was the hardest part. Boolean logic is of course required when programming some PLC's and even when working out cable runs there is some maths involved.
Mistakes cost a lot of money, I remember my boss ordering a role of 185mm² flex only to find it was not permitted so sat there unused until end of contract. Not sure what 100 meters of 185mm² flex costs but not cheap some thousands of pounds. So in industrial electrics one really does have to know what one is doing. However in some sections one never works with anything live, working in Belfast on the last ship made there nothing was made live during my whole contract it was a case of following plans, and not marking the glands, I spend days just putting tie wraps on cables. Unlike domestic every cable was marked and every wire in the cable was marked, and the plans covered every last detail.
Job interviews often one was give a plan and asked what is that? I have even been given a mini exam at an interview with questions like what size overload should a 3/4 horse power 3 phase motor starter have when wired as shown in the diagram. So maths required before you even step on the job.
When my son started there was no Part P and so builders and electrical firms could employ electricians mates to do the donkey work. Often it was in real terms cheap labour. As to if they still do this I don't know? However some way you need to work with other electricians. There is no way you can do a course and come out as an electrician. Although my son went as a sole trader by that point he had worked cards in with an electrical firm wiring houses so he knew what is expected, he also had family with dad, and grand dads all in the trade.
So you need to find some one who will employ you, minimum wage has not helped, in the days when employers could pay a pittance, they could afford to employ mates, today they are rare. My son worked as a mate wiring an estate of 30 houses, he only saw the electrician once a week as he came to inspect and test. Yet his wage was very low.
Other ways to get a start was to work abroad, the Falklands Islands Company would employ people with very low qualifications and they learnt on the job, again very low pay but all food and keep found, but they are no more. VSO was the same, many who worked with me started with VSO for a couple of years then found high paid jobs as a result. But voluntary work clearly only gives you food and keep, your wife would need to support the family at home.
My son took it in turns with his wife going to Uni. There are few ways of gaining the qualifications and experience without loss of earnings. Some families do have connections and can get their sons trained as helicopter pilots, but most of us don't have that luck.