A company was contracted to do installation of cameras in our school building. They would like to work on Chol Hamoed. Is this OK?
Work on items attached or being attached to a building may not be done on Chol Hamoed even through a non-Jewish contractor. However, in a location where it is well known that such work in this locale is generally done with a contractor and the workers are hired by the contractor without the owner having any involvement (this is the situation normally nowadays in most places), then it is permitted, provided that this is the case here too that and the contractor is contracted and not paid by the hour, and the owner has no involvement- and they are all non Jewish and you don’t instruct them to work on Chol Hamoed.
.מלאכה במחובר לקרקע – ה״ה כבנין
.ראה אדה״ז רמד, ב. ו
See Mekoros for similar issues here:
מלאכת תלוש ממש