NEVER LAUGH AT A CUSTOMER' S ABSURD MAINTENANCE SUPPORT CALLS !!!
At a Canadian telecom company we had a customer call in and report that their telecom equipment never worked unless someone flushed a toilet and then it was only for a few minutes afterwards. Fortunately, I resisted the temptation of howling in laughter or casting doubt on my customer's report. We dispatched a tech to the customer site and just like they said, none of the telecom equipment worked until a toilet was flushed. Further investigation revealed that the problem started after a plumber had done some work. He replaced a chunk of copper, sewer pipe with PVC. That copper pipe was their ground connection. The only time they got a ground was when there was a conductive water bridge in the PVC pipe.
Любопытно а их СНиП изолирующих вставок не требуют? И наличие хорошего заземления для зданий с АТС? На всякий случай для тех кто не понял, канадские парни использовали в качестве заземления трубы в здании и специально заземления не делали, и первый дятел сделавший разрыв сегментом трубы из ПВХ, почти разрушил им цивилизацию. Видимо не просто так в Южном парке над сортирным канадским юмором стебутся.