SJTFD responded to assist Northeast Fire and EMS on a reported Barn fire early this morning.   Fire 71 and 73 were first on the scene to find a barn fully involved with exposure problems.   Engine 142 arrived and layed a 5'' line up the driveway.  Engine 71 set up to draft from dump tanks.   A North Tanker Response was requested by Fire 71 while enroute as a large glow was visible from 3-4 miles away.   Approx 64,000 gallons of water was used to extinguish the fire and only the siding of an exposure building was damaged.  Cause was determined to be a child playing with a candle earlier in the evening.   Fire was reported at 0018 and all units cleared by 0430.