Re: CQD answer published Friday, February 20, 2015 - Gas Line Separation 2
Regarding underground electrical circuits, the National Electrical Safety Code (NESC) section 320.B.5 requires separation of underground electrical and gas lines. The specific requirement is "sufficient separation... ...to permit the use of pipe maintenance equipment." The NESC likely does not apply to the questioner's installation, but the logic behind 320.B.5 reinforces your recommendation to advise the customer "it is a better practice to provide separation for future maintenance and servicing."
As an AHJ I would apply the NESC separation requirement for all direct buried electrical circuits on our property. Your questioner should consult with his AHJ regarding local requirements for separation of underground electrical and gas lines.
Keep up the good work on the Code Question of the Day!