This is a very interesting problem and thread.
y3llow, the posters here have all provided some really smart advice. Everyone. Davewill explains what I think it probably the most clever, practical and strategic advice. I would take Davewill's advice and change it just a little. But I could not have suggested this without his idea. Great thinking - Nice effort Davewill.
If it was me, I would tell her that since she is the person with the concern, that she find an electrician of her choosing and invite him to come by to check the service as your residence. But because its her concern, she should pay for the electrican's bill/time. IF she doesn't like that, then you could offer to split the bill with her. I'd point out that she's the one with the concern, - not you and your lease does not cover it one way or the other. If she does not agree, with any of this, then ask if she will accept a report from an electrician of your choosing? If she says yes, then and only then, you add, that if your electrician's report states there's no permit required, that you are entitled to deduct the entire cost of the bill from your rent, since she did not accept your offer to pay for half.
If she agrees with any of this, I would put it in writing via letter, email or even text to insure she acknowledge "the deal" before you do anything. And before you hire an electrician, make sure that they will provide a report to you so you can pass it to her.