I was working last night on an electrical circuit that was shut off at
the breaker.

Nevertheless, the voltage from neutral to ground and from hot to
ground both measured about 30V. This was enough to cause my voltage
probe to buzz and to even cause a compact flourescent to light
dimly. The current across the circuit however measure just 0.7 mA.

Am I correct in assuming that this is probably just induced voltage
from neighboring wires that run alongside it or is there potentially
something more serious and sinister going on?

Thanks!