Devices, systems, and techniques are described for providing an indication of the presence of an electrical voltage potential at one or more electrical conductors and/or electrical terminals receivedin an electrical coupler. Examples of electrical couplers include an illumination coupling comprising a front flange, a rear flange, and an illumination channel extending between the front flange andthe rear flange and configured to encircle a portion of the electrical coupler. A plurality of illumination devices positioned at least partially within the illumination channel are configured to provide visible light emissions when illuminated that are indicative of the presence of an electrical voltage potential on at least one of the one or more electrical conductors and/or electrical terminalsreceived within the electrical coupler.