...why build the enclosure for electrical systems with MDF/MDP?
I have not seen any protection, you really should add an input circuit breaker, output circuit breaker with tripping coils attached to two 90°C paralled thersmostats assembled on the trafos cores
I used melamine coated particle board because it's easy, quick and cheap. And enables the enclosure to be the size and shape that I want,
These devices are my personal use only. They are for short term, interactive use only, and will not be operated unattended.
Obviously, I will be monitoring them for problems while in use.
I do not envision operating them in conditions that could come anywhere near to being a fire risk.
I had planned on thermo-switches and a fan for the isolation transformer, but dropped the idea given the above.
Should it become necessary, I can easily retro-fit a fan by cutting four wider side pieces to extend the box depth to accommodate a fan.
In fact, one of the first things I want to do with this thing is develop a temperature controlled fan circuit.
But I understand your concern, and I probably will end up retro-fitting such a fan and control system.
Or after using these things for a while, I may come up with new requirements, or ideas for other configurations and features. Maybe then I could incorporate all of it, your suggestions included, (and maybe the dummy load as well) into one of the larger metal enclosures that I have lying around here...
In any case, for higher power levels, I have the big transformers.
These things will almost invariably be operated from my variac, which has a circuit breaker and an RCD.
Why do You power panel meters with DUT circuit?
Not sure what you mean exactly.
In current limiter mode, the DUT is after the meter, so not a problem. But it is only useful for measuring current, as it won't be showing the voltage across the load. (though a mod to the meter may allow this)
As a dummy load, yes the meter forms part of the DUT/load, but consumes only 1.5W, and can be accounted for.
These things represent a starting point that provides what I anticipate needing at the moment, and I expect they will suit my purposes just fine.
But nothing stops me chucking all of it and doing it a better way if the experience of using them indicates that changes are needed.