If it feeds power to one of the loads OK, the other circuit that trips the breaker is looking into a short somewhere downstream.
I'd inspect the wires leading from that breaker to the load for a short caused by damages wires. If nothing looks bad, try looking at the load.
If the load is an item that plugs in, pull that plug and reset the breaker. If it holds, whatever you unplugged is the problem.
If the load is hardwired in, there is where you need to start looking for the short.
DG