1) The insurance company will more often than not sue the party responsible for the faulty workmanship that triggered the incident to recover the money (I've seen this happen). In this case the owner is that party.
2) One real example is enough to show it's not a legend and you provided it yourself:
> Some courts have upheld this rather cramped reading of the exclusion, while others construe it properly and require insurers to pay for the water damage
Since it's upheld in court I find your statement that it's an urban legend pretty confusing. It's like showing a picture of the night sky to prove the Sun is a myth.
YMMV of course, you should read your own contract to see what's stipulated and how comprehensive it is, and case law in your jurisdiction to see if courts would rule in your favor. But better be safe and start from the assumption that the "urban legend" is real since courts support it. It's the kind of legend that might cost you money.
Another? Didn't we clear this one already above when your link showed courts upheld the "legend"? Are you contradicting me or the courts? Feels like you're no longer looking for any evidence, just grasping at straws.
Plenty of resources that tell you that it's perfectly possible to get no payout (depends on your contract of course)[0][1]. Or they will pay out but capped to a low figure [3]. Again, read your contract and decide what applies to you, pray there's no fineprint to screw you over.
[0] https://www.boss.info/us/consumer_warning/
> unauthorized modification of electrical wiring may void your homeowners fire insurance policy
[1] https://www.quora.com/Is-it-illegal-to-do-electrical-tasks-w...
> Most jurisdictions require a permit to be pulled for most electrical work
[3] https://www.reddit.com/r/HomeImprovement/comments/7vwe23/doe...
P.S. No, I do not know any cases where the owner was sued but I do know many cases where the insurance company payed out and then sued the company that did the faulty repairs to recover the entire payout. I also know one case where a faulty repair done by the owner caused a fire that injured the tenant - the owner was found guilty of recklessness/gross negligence (no idea about the insurance in that case).
Here is a link to a sample Homeowner's policy: https://www.iii.org/sites/default/files/docs/pdf/HO3_sample....
Exclusion B on page 12 is probably the relevant section. It excludes loss due to "Faulty, inadequate or defective:... workmanship, re- pair, construction, renovation, remodeling,..." but also contains an "ensuing loss" exception.
Here is an article about that: https://www.irmi.com/articles/expert-commentary/ensuing-loss...
> A classic example [of an ensuing loss exception] is if faulty repair resulted in improper wiring and the improper wiring caused a fire. Almost every insurer would pay for the fire damage, but not for the repair of the improper wiring.