When you open your electrical panel, does it have a Zinsco label? Hopefully not. When I come across a Zinsco panel, such as this one the other day, I have no choice but to recommend a full analysis by a licensed electrician. The reason?... "Problems with certain Zinsco panels cannot be seen by the naked eye. Even after the cover of Zinsco panels has been removed, everything can seem to be in fine working order. Upon exploring its components, electricians find that breakers cannot be removed from the bus bar. They’ve welded together, which indicates that the breakers have melted. In that condition, a breaker would be unable to trip and may be allowing an unsafe amount of electricity into the home! This could lead to a potential fire." (ref: http://www.ismypanelsafe.com/zinsco_damage.aspx)