A lampholder has an inner part centered on an axis and formed with a radially extending and axially open inner slot having a predetermined small width. It also has an outer part surrounding the inner part and formed relative to the axis with a radially extending and axially open outer slot of a predetermined large width. A lamp pin of a width greater than the small width but smaller than the large width cannot slide through the outer slot into the inner slot. The inner part is separable from the outer part.