It's a code violation, not insurance fraud.

I read about this often whenever I'm looking at guidance for one of my hobbies, and often people are dealing with it in their garage. Some jurisdictions are more okay with DIYing than others, but it's all too common that someone is taking 240V, 30A and going to an enclosure that they built to get 3+ HP/2+ kW at 240 or 480V, three phase.

The common refrain is that your insurance will deny your claim.

The response that people get when they call their insurance is "you pay us to cover you even when you do the wrong thing". Just like how your auto insurance covers you when you rear-end someone while drunk as hell, when you drape way too many lights on your crispy dead Christmas tree, or when you fall asleep and light your drapes on fire with a cigarette.

Intent is when you set out to cause an accident.

(You should probably read your actual insurance policies before considering my not-a-lawyer American-centric comments.)

It really couldn't. "Intentional" as it, you destroyed your property on purpose. Not "you were a dumbass and caused damage", not "you didn't apply for a permit and caused damage". Insurance covers stuff like that, because otherwise, a good half of claims could be getting denied. Basically all kitchen fires are "dumbass moments", for example.

The third option is hiring someone to certify it, usually requires submitting the plans beforehand. Afaik up to 800w you can do a lot DIY here but upwards you needs certification.