A self-contained branch circuit monitor 2 is has a small form factor configured to fit in the limited space available in a load center 1, in association with a branch circuit breaker 10A occupying a branch location slot 45 in the load center 1. A flexible printed circuit board 4 is wrapped around an outside circumference of a toroidal sensor coil 6 of a current transformer. A current monitoring circuit 15 is formed on the flexible printed circuit board. The monitoring circuit is electrically connected to leads 7, 9 from the sensor coil and is powered by current 17 induced in the sensor coil from current 5 in the branch circuit wire. A branch circuit wire 3A is threaded through the current transformer's center. A transmitter 22 is part of the flexible printed circuit board, to transfer the monitored current data to other locations.