Do you have a Zinsco, Federal Pacific Electric Company (FPE), or just an outdated panel?  

Most Zinsco and FPE panels are obsolete today. However, at one time, they were extremely popular and installed in many regions throughout North America. As time has passed, electricians and home inspectors have discovered that certain Zinsco panels often can fail to operate properly and may leave homes and homeowners at risk to both fire and electrical shock. These panels can work fine for years, but as homes have increased energy demands, these panels may overheat and portions of it melt. In this situation, if a breaker melts to the bus bar of the panel and can no longer adequately trip in case of an overcurrent or short circuit, an extreme amount of power from the outside electrical supply surges into a home’s panel and circuits. Once that happens, it cannot be stopped or shut off manually. Electricity will burn until it runs out of fuel or the wires melt. The panel could overheat and catch fire, causing serious harm to a home and its occupants.