Is it ever OK to have a double posting in an electrical/ circuit breaker box? If so. When? Thanks for your help.

Can you restate your question, not sure what you need. Do you mean a double pole circuit breaker? 2 pole CB are generally used for 240 colt circuits like electric ranges, dryer, water heater, (note, not a hot water heater, only kidding).

Beyond this, I am not sure what your question is, please post back and we can go from there, unless someone else knows what you mean.

Maybe he means double tapping a breaker. 2 wires to a single breaker. The only breaker I've seen to accept double tapping would be Square -D with the type of screw down on the breaker. Don't believe code allows double tapping.
Right TK?

That is correct, code does not allow for multiple wires to be in any wire connector or terminal, unless the device is rated by UL to accept multiple wires, and is labeled by the manufacturer that the terminal is for multiple wires.

Also correct, Square D is the only brand of circuit breaker that comes to mind that allows for two wires on their QO , QOB, and their HomeLine frame breakers.

That is a good point you brought up that the questioner may had been referring to, since I am not sure what is meant by "double posting", and why I asked for clarification.

The poster must be all set since I did not get any answers to my request.