Contact wear detection by spectral analysis shift

A contact wear detector includes an electrical contact 100 having a base layer 110 composed of a first material and a contacting layer 120 composed of a second material, to electrically contact an opposing contact in the circuit. The base layer is capable of having portions exposed through worn areas 125 of the contacting layer. The first material of the base layer is configured to form an arc 210 between the portions of the base layer exposed through the worn areas and the opposing contact when the contacts separate. The arc thus formed emits light 212 having a characteristic optical spectrum of the first material. An optical detector 220 is proximate to the electrical contacts, to detect the characteristic optical spectrum of the light emitted by the arc between the portions of the base layer exposed through the worn areas and the opposing contact.