Quote from @Matt Devincenzo:
While electricity falls under habitability, the only issue with habitability is due to the tenant's actions. I would not cover their hotel...there's no obligation to EVER cover a hotel stay. You can also simply not charge the rent for times where the unit is uninhabitable.
In this specific instance I'd likely collect rent and not cover accomodations. If I was asked to I'd remind them this situation was caused by their action and has cost me to remedy, and ask why they believe I should be reaponsible for their accomodations?
I think a lot of this depends on where you live. Here in Colorado, a new covenant of habitability law passed recently and if the tenant requires a hotel stay, then the landlord is responsible for it. In the case of the OP, it's California so the standard to meet may be higher.
Yes, the tenant is responsible for the original problem but it uncovered a new problem. In California, who is responsible for keeping the electrical up to code? Hopefully, the landlord can get this done without incurring extra costs.