as pauluk said you would be reading voltage via some other 208 volt breaker feeding through a load.working back to the source for that panel until you get voltage between phases narrows down the problem area.question though,could a amprobe be put on the phases and look for the low or no existant amperage on the feeder to narrow down the offending bad phase. this reminds me of a tip to offer.some of you have been to a building with partial lights and sproatic power outages throughout building and know that there is a lost phase.besides checking the neighbors and opening panel, go out to the meter and look for a missing or flashing a,b or c.then you know its on the poco side.
