The 6mm cable is not at risk of overload, the 32A trip that covers it sees to that. The 25mm main similarly is covered by the 100A fuse.

But, there is a lot of load in those boxes compared to the supply to them, especially the 2nd one if you use the textbook approach.

So are there mitigating factors that may justify a non- standard calulation ?-

Are there 2 socket circuits not because they are needed to serve a massive heavily loaded area, but instead perhaps serve only a small space but are used to keep IT equipment on its own circuit or to provide some other segregation by room or load type?

If so then they may not be as heavily loaded as one would assume.

Do the 2 water heaters never come on together  for some reason or maybe have very short duty cycle? - it may be alright in practice if they are only both on for a few minutes at a time. Are the heaters taking the full 16A each or is that the breaker size but really they are much smaller load ? 

Or is it all loaded to the max and tripping every other day ? If so it is just wrong, and needs some cable and breakers changing for the next size up. It may have been added to in stages over the years without too much 'bigger picture' thinking.

But these are the questions I would be asking.

Mike.

The 6mm cable is not at risk of overload, the 32A trip that covers it sees to that. The 25mm main similarly is covered by the 100A fuse.

But, there is a lot of load in those boxes compared to the supply to them, especially the 2nd one if you use the textbook approach.

So are there mitigating factors that may justify a non- standard calulation ?-

Are there 2 socket circuits not because they are needed to serve a massive heavily loaded area, but instead perhaps serve only a small space but are used to keep IT equipment on its own circuit or to provide some other segregation by room or load type?

If so then they may not be as heavily loaded as one would assume.

Do the 2 water heaters never come on together  for some reason or maybe have very short duty cycle? - it may be alright in practice if they are only both on for a few minutes at a time. Are the heaters taking the full 16A each or is that the breaker size but really they are much smaller load ? 

Or is it all loaded to the max and tripping every other day ? If so it is just wrong, and needs some cable and breakers changing for the next size up. It may have been added to in stages over the years without too much 'bigger picture' thinking.

But these are the questions I would be asking.

Mike.