It's very unsatisfactory for you.
In the 'old' days when apprenticeships operated, one had to serve one's time like this, more recently coupled with a day release C&G type theoretical training. But at least one got the ticket after serving the time.
Now, unless you have the ticket, you can't get the tradesmens rate and the economic climate and loss of apprenticeships means there is a lot of this sort of thing going on.
There are several jobs, of course, that you cannot legally do, and if you are not being directly supervised you could decline those - those involving gas, oil or high-pressure fittings.