I have a group of wall receptacles (approx 10) that are not working. The circuit breaker is not tripped. The circuit breaker has not failed. In fact, all the CBs on the main panel test out OK. None of the receptacles has a GFCI. What can I do next to determine the problem?

Do you know if the outlets are wired back to a junction box or is it a chain of outlets with power fed into first one, then out to the next, etc? Either way, you need to find your first point so you can inspect the connections there. Is any of the wire access able to trace, i.e.. Drop ceiling ?

Okay,

Other than the receps not working, how have you determined "what" the failure is?

Have you used a multimeter to see if there is voltage at any of the receps?

Have you verified, with a meter, that there is voltage at load side of the breaker?

Can you give us anything more than, "It's broke?"

First, reset all single breakers that could possibly control this circuit. Some breakers do not move very much when tripped. This will insure that the breaker is reset even if it doesn't looked tripped.
Next, pull one of the non-working outlets and see if it was wired using the "quick connect" holes in the back. These are know to develop bad connections over a period of time.
If wired using quick connect holes, rewire putting wires under screws. The bad connection can be at the first non-working outlet or switch, or it can be at the last working outlet or switch on that circuit. The bad connection can also be in the hot or the neutral. Do a voltage check between the hot and the ground. If you meter shows voltage, the bad connection is in the neutral. With that knowledge you can then determine which breaker controls the circuit.
If after rewiring the nonworking outlets, they still do not work, you will have to try to find last working outlet on that circuit and rewire it. If you can determine which breaker controls this circuit, turn it off and take note of what outlets do not function. That should point you to the last working outlet.






You can always just rewire all of your outlets and switches using the screws. Chances are that this problem will keep occurring until you do.