has anyone successfully fitted 10mm cable, 45A switch, 1gang backbox?

[Mark42]

... I realised that I missed the discipline and teamwork. ...

Yup. This is why I usually operate in a committee/team of one: getting decisions is so much easier ?

Ref your question: Have you considered scrapping the first plan and re-routing to a big, over-specified rotary isolator in a cupboard? I did the same with some high-current bathroom fittings (see pic). So much easier to make neat and long-lasting terminations, especially on long runs with heavy cables.

The way things are usually done is not always the best way. I have similar arguments discussions here a lot!

 

[MrMan1O1]

The way things are usually done is not always the best way

Totally agree. It's ok to say "it's always done like that" if backed up with a good reason, but to blindly follow is foolish. It's best to always be curious.
I've recalculated for a 10mm cable and I can use a cooker isolator with socket outlet as even with the 5A added for the socket the load is just under 32A, therefore I reckon the double backbox should give me the room to fit the cables in. I do like your plan B though....in my previous life I would never brief a plan to a senior officer without having a plan B in my toolbox!?

 

[Rockingit]

Not something that I'd recommend as normal behaviour, but, in similar situations in the past I have literally just butchered out the back of the box to make space - amazing how quickly a 50mm holesaw can make a cable bend.........

 

[Simon47]

Goodness me I could never work in a submarine for love nor money! Terrifying!

Did part of my apprenticeship putting them together. Luckily I never had to work in any of the more cramped bits. Worst was having to crawl on top of an air handler (just a fan-coil air cooler) in the engine room and lie on my chest with backside against a hull ring and legs dangling while wiring the darned thing up. Compared to that, it was cushy doing many hundreds of over-moulded inline connection up front in the sonar space.

Of course, even the best jobs are a bit ruined if there happens to be a team of caulkers working on the boat. Think "working in a tin can, while someone's beating the sh*t out of it with a windy chisel" ?

The subs I worked on are out of service now.