Bonding to Gas Lines To the Editor: The article "Electrical Code Update" (7/99) was quite informative, but the point on bonding of gas pipes needs further explanation. When the utility providing gas service to an occupancy uses a dielectric union, then gas piping must be bonded in accordance with NEC 250-104 to ensure that piping inadvertently energized has a continuous path of equal potential to the electrical system ground for clearing of faults and personnel protection. The problem occurs when the installing utility does not provide a dielectric union. In my local area, the utility will red-tag gas equipment if bonding is installed by the electrician. According to my local inspector, this is because when the dielectric union is left out