In my service panel I would like to [upgrade two standard circuit breakers with AFCI breakers](http://books.google.com/books?id=fR7ZWfC06rIC&lpg=PA173&ots=Abm2lMd85Y&dq=%22find%20the%20white%20wire%20on%20the%20circuit%20you%20want%20to%20protect%22&pg=PA173#v=onepage&q=%22find%20the%20white%20wire%20on%20the%20circuit%20you%20want%20to%20protect%22&f=false).

AFCI circuit breakers differ from standard circuit breakers in that you attach the hot an neutral to the breaker, and then attach the AFCI's coiled white wire to the neutral bus bar. With a standard circuit breaker, the hot wire is attached to the breaker, and the white wire is attached to the neutral bus bar. Here is a diagram of an AFCI breaker:

![Image of AFCI breaker](https://i.stack.imgur.com/6Hshw.jpg)

I shut down the power to the panel, remove the cover and now I need to find the neutral (white wire) associated with each circuit. I see a dozen white wires.

I know which wires are the hot wires for each circuit, but how can I determine which neutral wire is part of that same circuit? I can make some guesses based on the style and markings on the insulation.

![Service Panel image](https://i.stack.imgur.com/ASKMU.jpg)

And for the record, all of these circuits were installed by licensed electricians. And yes, they used blue wire on some circuits, which is a bit unusual but not unheard of.