I went from self employed to on the cards, haven't looked back since.
Set myself up a nice little business a year after finishing my apprenticeship. Started out bashing houses but very quickly left it behind in favour of commercial and industrial work as my company grew. The domestic market is a free for all and the vast majority of 'successful' domestic electricians making good money aren't electricians but businessmen. Chancers that make their money by paying a load of apprentices peanuts and charging what they can get away with for rushed and shoddy work. It's next to impossible to compete with them. I only know a handful of sparks who stay as one man bands and bash houses for £150 a day (its doable with minimum overheads). They're content with knowing they'll never grow or progress their business and all power to them. But that wasn't me.
I kept my toe in domestic work by doing EICRs but we never carried out remedial work. It was a good way to market the business as a lot of landlords cottoned on pretty quick that we weren't there to just invent jobs that 'needed' doing.
The more we moved into the corporate world the harder we found it to compete also. The minute you find yourself competing with national companies the more you find yourself being undercut as they can afford to take clients on a loss leaders.
The only way we managed to stay profitable was finding a niche, but we had to travel far and wide for the work. We developed good relationships with a few key clients and kept their work because we were leaders in the field and we looked after them. The majority of successful electricians go this way. They find a niche industry and become specialists in their field. It takes a lot of learning and a lot of dedication. I never stopped putting down books and I spent a lot of time actively seeking out opportunities to surround myself with people who knew more than I did. You may be able to apply your skills to this given your background with process control (not a million miles from what I was doing with my company in the end), but it will take time. You'll struggle to find a stable customer base for years only doing that.
The electrical industry is incredibly hard to compete in now. Its saturated and nobody values quality. That said, I did run a successful business however it came at a significant cost to my personal life. 70 hour weeks were really taking their toll.
I ended up being headhunted after making contacts in the railway industry whilst teaching part time. I was made an offer I couldn't refuse. Eventually I stopped resisting, sold up and moved on. Initially I took a fair sized pay cut but I'm telling you this, 35 hour weeks, 30 days holiday pay, 6 months full sick pay, the ability to turn off my work phone when I leave the office and never ever ever having to spend another day with the anxiety over next months wage bill never felt so good!
Now after two and a bit years I'm earning what I was with considerably more benefits and I have only a fraction of the stress. I've also enjoyed learning a whole new set of skills and a specialist set of knowledge in a whole other area of the electrical industry. I also enjoy the fact that there are never a shortage of learning opportunities where I am now.
My advice, think very very carefully before jacking it in and going your own way. The grass may appear greener, but there are only two ways to actually achieve it;
1. Legitimately, with patience and years of grit, determination, sleepless nights and a good few years of running at a loss, or
2. Illegitimately, by sacrificing your principles and being prepared to cut corners in every way imaginable.
There will be others who will give other examples of how its possible, but they will likely be the exceptions, not the rule.