I recently ran a branch circuit to the exterior of the house to add a receptacle on the patio. The existing 15 amp breaker protected a circuit that had only three plug outlets and one switched ceiling light. The circuit is very lightly used. So I want to add GFIC protection in the form of a breaker in the service panel.The existing breaker is a single pole 15 amp breaker. It has only one wire to it (black). The 15 amp single pole GFCI breaker that I purchased to replace it has a white pigtail on it. I connected this to the buss bar and the existing black wire to the load lug on the new breaker. It trips as soon as I try to switch it on. Can anyone help? The directions that came with the GFCI breaker show a white wire attatched to the neutral lug on the breaker, but there was no white wire to the original breaker. Thanks. Dave.