Clowning around
We had some electricians in at work today, pulling in some large cables in preparation of a forthcoming upgrade. The cables are 300mm² steel wire armoured, capable of handling more than 500 Amps. (By comparison, domestic wiring for sockets uses 2.5mm²). Eight of these cables are used for our main building supply and they are extremely un-bendy. I often think that the work of an electrician is as much about mechanical engineering as electrical engineering.
Then, a couple of hours later, the lights went out. This always gets us worried, as whilst we have big power systems to take care of this, it causes a fair bit of disruption of non-critical systems. After a quick trawl round various places, we found the reason, one of the electricians had accidentally operated the main switch. He had put it back on immediately, but as we have a backup generator system, the control gear immediately took over and transferred the load onto the generator after a short interval. (Short, but it felt quite long at the time, some twenty seconds or so). The reason he had tripped it was a rather silly one and there is a clue in the photo shown here.
