A very common question many people ask is whether or not they need to upgrade their electrical service. All structures have limited electrical capacity. When a service is upgraded or changed, that capacity is increased, allowing the potential for more circuits to be installed and used.
Many homes and businesses still have their original 100 amp service, so when it comes time to remodel or add an addition, often there is little or no room in the distribution panel to install the required additional circuits. The amount of electricity available is limited by the capacity of your main breaker. So when major appliances are added, or the size of the building is increased, very often the electrical capacity of your service needs to be increased as well.
In addition, many electrical service units have been hanging on the side of buildings for a long time, subject to deterioration caused by the environment and weather. Some have become damp and corroded; some have been overloaded over the years and due to overheating; joints and connections may have also become loose. Some services still rely on fuses. With age, fuses can often become corroded, overstuffed and overheated. These conditions are dangerous and are good reasons to invest in upgrading your service.