In a home’s electrical wiring system, there are certain colors of wires that are supposed to serve different functions when wiring in a home’s electrical panel. Green wires or bare copper wires are used for grounding purposes. The code has specified this for many years. Likewise, white wires, are considered to represent the neutral in a home’s electrical system.
Using the standard color codes, one would use green wires for grounding wiring and should be connected to the grounding bar in an electrical panel. White wires would represent the neutrals and should be connected to the neutral bar in the panel. However, there are some instances where we do not connect the white wire to the neutral bar, but to a breaker, such as for GFCI breakers. In some circumstances this is proper and in some it is not.
When is it OK?
Special breakers will have a white wire running to them. i.e. GFCI and AFCI breakers. This is acceptable.
Note that it is not unusual to have an A/C installer to use a white wire for a hot going back to the breaker. What he should do is to wrap the white wire near the breaker with a piece of black electricians tape. This will indicate that he is using it as a hot. However, many electricians fail to do this. It’s very easy to wrap the wire with black tape for short distance on the wire, but a home owner shouldn’t do it because he may accidentally touch a bus bar or hot wire and get shocked or injured
Who to consult? An electrician or home inspector.
Electricians and home inspectors can usually determine if the situation presents a risk or not. Often there is no risk or if a change is necessary; its easy and quick.