Expect your power to be out for about 6 hours on the day the job is done, or longer if it is more involved. You may experience circuit breakers tripping. The reason for this is that on some old services, especially fuses, the circuits were over protected by the previous owner to eliminate blowing circuits. Electrical service upgrades have helped some customers by lowering their energy bills, most likely after another factor affecting energy use was repaired.
When we do the service upgrade, we install the proper circuit breakers according to the wire size. If this occurs, you may need to have some new circuits installed to alleviate this problem.
Bretco has completed hundreds of service upgrades in the Winston-Salem area. A service upgrade can be expensive but necessary to bring your addition up to code. Overloading a small panel with add-on circuit boxes can be dangerous. If this applies to your service panel, give Bretco a call and make sure your smoke detector is in working order.