From my perspective, the educational qualifications now required to teach / assess a subject are not insignificant and are generally at a higher level that the trade qualification required. In essence, an understanding and knowledge of eduction practice is valued more highly than the trade skills you are teaching. I’ll let you draw your own conclusions on that.
That was a fantastic post! To follow on a little on the subject I have quoted from you, I think I can give a little input. Although I hold a different teaching qualification to the one you mentioned (things are often done slightly differently here in Guernsey in comparison with the UK) the principles of education will be the same.
The teacher training focuses on a few main areas at level 3 and goes more in depth at level 4 as one would expect.
The main areas, all relating to the student, are:
Initial Assessment e.g. Finding out a learner's current knowledge before they start, their level of experience if any, their learning style or preference (Auditory, visual, practical hands on) their ability levels, their expectations for the course or qualification, what will be expected of them, ground rules, where they see themselves in future, that kind of thing.
Formative Assessment e.g. As a student is working through a task, how they are managing, any gaps in knowledge needed to be filled to complete the task, how they are coping, do they need more support, what they might need to improve or focus on to achieve and using your peers for formative assessment and feedback.
Summative Assessment e.g. Looking at the finished article, marking, feedback, areas of strength and weakness "uncovered" by the task being completed, resubmissions where the agreed/expected standard was not met, praise, what went right, what went wrong (feedback) and progression.
The teacher training also focuses on various teaching methods for example, demonstration, question and answer, handouts/online resource links, competition, assignments, research tasks.
You will be expected to have a good understanding of these methods, how and when to deploy them, their advantages and limitations, how students of different types and abilities might react to or benefit from the various methods and justifying why you chose those methods.
Then there is all the stuff about equality and diversity, how you will tailor a course to the individual and their special needs if any. Nobody must be excluded from learning because of these things, all within reason of course. For example if the job/course entails climbing around scaffolds and wind turbines a wheelchair user could not be reasonably accommodated but every effort must be made, again within "good reason" with regards to cost and practicalities.
There is also a lot of focus on lesson planning for group activities, individual activities, tailoring lessons to suit individuals, risk assessment, how and why you will use various methods and when. You must state objectives and desired learner outcomes in your planning and how you will achieve that using your methods.
Finally just like plumbing there are a lot of education specific terms and language used which you need to get to grips with to get by but that is all part of the progression and training in becoming a teacher.
As you can see, there is nothing plumbing trade specific in there. It is all about methods of teaching. It means that - up to a point - one teacher can teach another's subject or at least transition more smoothly. Educating people is most certainly a trade in its own right. The subjects change and the individual methods change but overall teaching is done within a framework that is transferable between subjects.
I hope this helps those to understand a bit more about the subject of teaching. I'd like to finish by saying that before I undertook my Level 3 Award in Education and Training I had no idea about any of this. I finished the course with nothing but the utmost respect for teachers and what they do to get there.