A sealing arrangement for sealing a quartz tube with a UV lamp therein and electrical cable extending therefrom through the lid of a pressurized fluid purification vessel. In one version, a tubular fitting, threaded on opposite ends, is received over an end of the quartz tube and threadedly engaged in an aperture in the lid and sealed with a first annular seal, a second annular seal in the tubular fitting seals about the quartz tube. A compression nut with an axial extension threadedly engages the opposite end of the tubular fitting and a strain/flexure relief is threaded into the axial extension. In a second version, the second annular seal comprises a flexible sleeve with a member having resilient radially deflectable fingers compressed thereon by a compression nut; and, duplicates of these parts employed to seal about the electrical cable.