My house breaker box have only breakers which seat only 1 wire. No seat for a load neutral. Literally one screw on the breaker. There are neutrals on the bar and everything works no problem. I want to protect my circuits with GFCI breakers but they have 2 seats, 1 for the load hot and one for the load neutral, but my box has no load neutrals going into the breakers. Can someone tell me if I can just plug the hot into a GFCI breaker and plug the pig-tail into the bar, and leave the neutral seat on the GFCI breaker empty? And if so, will I still get GFCI protection in this way?
Lastly, why were boxes/homes wired this way? What are the advantages and disadvantages to this type of box? (where every breaker has just a seat for hot and there's no neutrals running around and the only neutrals seem to go directly into the bar?)