Don, the analogy I would use here is automobile seat belts. It is unfortunate that there were thousands of people that died in accidents in older cars after seat belts were mandated. It is the nature of safety codes that they cannot cure all existing unsafe conditions. There are, unfortunately, about a billion circuits out there that will not get this protection for 10-15-20 years or more. By changing code, we've started down a long path of providing increased fire protection. Over the next 15-25 years before those breakers are changed out, we could lose as many as 10,000 folks in residential electrical fires (400 a year for 25 years). That total is more than three times the number of folks that died in the World Trade Center. However, since these folks die one or two at a time, this does not get the attention that it warrants.
It is unrealistic to change out all existing circuits at once, but if we never start, the conditions will remain the same. When GFCI was added to the code, it was not mandated for existing conditions. There are still homes today that are unprotected by GFCI, and there are people that are electrocuted in those homes. When I added an outdoor circuit to my 50-year-old home, I added a GFCI breaker. That breaker saved my four-year-old daughter's life. If the electrical code had never changed, it would not have been standard operating procedure for me to add that protection, and my daughter would not be here today.
