I recently had some building work done (by a company that carries out work in schools) and purely by chance I found that they had taken the earthing of the electrical wiring and failed to replace it. This may seem like a small thing but, recently there was a story in the newspaper about a man who got electrocuted in his shower because the wiring wasn't earthed.
What has that got to do with schools? Was the work you are talking about done in a school? Schools, unlike private home owners, do have to ensure that work carried out on their premises complies with health & safety regulations and have to do regular checks and audits, so something like that happening in a school should be far less likely than the same thing happening in a private home.