When new circuits are needed for a renovation, or new appliances, but the existing service panel is full, a service upgrade is often necessary. However, some conditions may only require replacing the main panel rather than doing a complete service upgrade. The most common reason for this is when there is enough power to the house, typically 150 or 200-amp, but with a small panel that is full. In these instances, the panel is replaced with a larger one, a new painted panel-mounting backboard is installed, and all the grounding is updated.

Another reason to replace a service panel without a complete upgrade, is for instances when the service panel has been damaged from overloading, water damage, or to replace a panel type known to be hazardous such as Federal Pacific Electric. These panels, commonly called FPE-panels were widely used throughout the 1960s and 1970’s. These panels and accompanying Circuit Breakers were found to be highly unreliable during short circuit conditions and indirectly the cause of many electrical fires. Investigations found the company was doing their own laboratory testing and not reporting or correcting the high rate of defective products.