A320 Captain discovers inoperative oil pressure gauge after first engine start and a tripped circuit breaker. Breaker is reset and flight departs. Enroute breaker trips again and is left out. After discussion with maintenance flight continues to destination where it is discovered that a chaffed wire was causing the problem.

Narrative

I reported to the plane for my flight to SFO and read all the paperwork and noted that the #1 eng reverser was inoperative and secured for this segment. Read and was aware of all the penalties associated with this deferment. We were a little late to push due to the security lines at the airport. Upon push back we started the #1 eng--normal start with the exception of 'no oil pressure gauge' all xxx's in the gauge. Apparently I overlooked this circuit breaker (n40) being popped on my cockpit setup. After airplane movement stopped and brakes set; I pushed in this CB. The gauge came back; started #2; taxied and took off. Several minutes after take off; this gauge went to xxx's again. I looked back and this same CB (n40) had popped. We sent a message to Maintenance relaying this information and also our dispatcher and asked if we should drop down and have this fixed. This dispatcher notified us that he was on a conference call with maintenance and the flight ops duty manager and will let us know. Several minutes passed and then the dispatcher established radio contact with us. All involved parties agreed that the primary method of determining if there was no oil pressure was through the ECAM system which was a separate system than the gauge itself. We were all comfortable with the decision to continue the flt to SFO. Uneventful landing and taxi to gate. I did paperwork for my next assignment. As this plane was still at the gate; I went aboard and spoke to the new cockpit crew and told them the what happened. I then went outside and spoke with the mechanics working on the engine. It turns out that a wire was chafing that caused our problem. Wire was replaced and flight left.