If the installation is made unsafe by tenant abuse, then that's their own fault.
INdeed, that's how it
should be. Unfortunately, these days if a tenant is injured by their own stupidity, the question (to someone else) is "why didn't you prevent them harming themselves ?
To improve standards, certain things should be made mandatory in all rented properties.
These would include such items as RCDs for all circuits, a minimum number of socket outlets for each room, suitable lighting for all areas, etc.
Certain items such as rewireable fuseboxes should be banned completely - most people have no idea how to replace the wire correctly and the possibility for misuse is huge.
I see your point, but how far should you take this ? Already many things are mandatory for rented accommodation which are not for owner-occupied houses. The most obvious is gas safety checks every year. Others are coming along in the not too distant future - minimum energy ratings being one. I can see the point, but some properties are by their nature very hard (and costly) to insulate - I can imagine a few being uneconomic and leaving the rental sector.
But as landlords we already have to provide an EPC to prospective tenants - so there shouldn't be any question of a tenant not knowing in advance that a property will be hard/expensive to heat and in principal market forces ought to fix the problem (as in, properties with poor EPC ratings should be harder to let and fetch lower rents). This seems to be a case of tenants not looking out for themselves - and others being forced to do it for them. Lets face it, is anyone (at least anyone capable of entering into a tenancy agreement) really so dim that they can't figure out that a (say) F rated house will cost a lot more to heat than a (say) C rated one ?
But back to the lecky side. RCDs - not really a problem. No rewirable fuses - again not really a problem. In reality, if a property still has no RCD and rewirable fuses then that suggests it's somewhat overdue for some upgrades ! But what is an acceptable number of sockets in a room ? What is acceptable lighting ? Both are subjective measures, and always open to someone coming along and claiming that their subjective view is more reliable than someone else's. But again, if you enforce this, then the rent will have to go up to cover it - so you risk actually causing more harm than good if it then prices someone of limited means out of their home.
Probably close to none, and the few that are would generally be blatantly obvious to anyone, such as broken fuseboxes, missing covers, sockets hanging off the wall etc.
If I could think of a way to search for it I could find at least 1 post here from a tenant reporting a problem as egregious as those where the landlord or agent (who had been sent the photos) was refusing to do anything without a report from an electrician.
So in reality, we're back to "Part P" statistics. Because "some small number" of tenants have a problem like that, then "all landlords" must do something. What the tenant should have done is call their local council about the fault. If they can show that the landlord has been informed, and has refused to fix a fault, then the council can (and does*) issue an improvement notice on the landlord. If the landlord ignores that, then the council can (and does) deal with it - that can mean various things, including arranging a repair and billing the landlord, declaring the property unfit, and prosecuting the landlord**.
* One of the guys at work had this. His rented house was damp and mouldy and the landlord didn't fix it - the council issued an enforcement notice on her, and then it got fixed !
** There was a case not long ago when a landlord was fined over £20k for breaches of regulations - in that case relating to an HMO. It was pointed out by the prosecuting council after the case that the improvements needed (and which still had to be done before the property could be let again) would have cost a lot less than the fine.
So the tools already exist to deal with what most of us suspect are fairly uncommon events. If you are going to argue that that isn't enough, then what next - a mandatory inspection to check the condition of the sanitation, structural survey, checks for damp, and so the list goes on and on.
I feel a letter to my MP coming on.