the only thing i can think of is a harness for horses looking on the 1891 census there are a few people involved in this in the st. nicholas/old machar areas of aberdeen
after seeing christoper's reply i had a look at the 1901 census for aberdeen and the harness makers for horses seem to be described as "saddler and harness maker" so an electrical harness might be nearer the mark possibly linked with marine engineering do you have a name ysabeau ? a look at the census might provide an answer