Pumping Supplies & Installations Ltd. We are now an authorized certification authority for self-contained vehicles. For camper plumbing and fittings, check out the Maclon link or visit our shop at 15 Sydney Street for pipes and fittings. We also have a certified gas fitter for repairs and gas safety certificates. Selling RVs with gas installations Sellers must take ‘reasonably practicable’ steps to ensure gas safety, whether selling privately or commercially. All gas work must be done by a licensed gas fitter and signed off by a certified gas fitter. All altered and new work must be added to the WorkSafe high risk website.