It might be her service is limited. I have a 200 amp service. I know some on this forum only have 100 amp service. If you go out to the outside of your house where the power meter is you can lift the cover and see the main circuit breaker. It will have a number like 100, 150, 200, etc. That is the maximum power you can draw with everything in your house. Now go to the main circuit breaker panel in your house and add up the numbers on the circuit breakers serving your house. The difference between those two numbers might be why the electrician is saying you can only handle a 50 amp service.
Scott :-?