I had a case where my place's electricity was off for a couple of days. It was due to a fault on the municipality's side of the DB, so not something I had much control over. My tenant threatened to move into a guesthouse on my cost, as the place I rented to her was untenable(no electricity). I consulted a lawyer who agreed that she could do that. Luckily for me, she spent a couple of days with a friend, until the electricity was fixed.
The law protects the tenant - if for some reason the place becomes untenable, the landlord has to provide similar alternate housing, or be in breach of contract.
