Abstract: A luminaire apparatus includes a luminaire housing body, an electrical cable member and a power source. Means are combined with the cable for compressibly securing one end of the cable in the housing in a position to provide an effective moisture seal and the cable jacket is held in fixed relation to the housing so that strain or pulling forces exerted on the cable are not transmitted to electrical conductors contained therein. When the power source is a battery of the class used in a miner's cap lamp apparatus, for example, in which the housing body is a headpiece to be attached to a miner's "hard hat", the electrical cable may have an opposite end sealably engaged in the battery top, and provided with a strain relief member. A portion of the cable extending inside the battery top is held in a cable locking device so that pulling forces exerted on the cable are not applied to electrical conductors connected to battery terminals.