On 12/06/18 10:06, Mal Rowe wrote:
> I wonder if during the construction phase some of these safeguards are
> not yet implemented?
Not enough infrastructure is in place yet at that location to need them
yet. It's simply a construction site.
> I wonder what structures like fences are 'earthed to' in Sydney?
The metal fences on stations are bonded to the stanchions / running
rails to ensure there is no touch potential between the metal fence, the
stanchions or the body of a train at the platform.
Continuous fencing alongside the railway now has 'insulating panels
(i.e. wooden fence posts) every 50-100m to break up the electrical
conduction path along the fences.
A few years ago a station cleaner decided to vacuum a train parked at a
platform. With their back-pack cleaner plugged into the 240v in the
station they walked onto the train and started to vacuum up rubbish.
They then suffered a fatal electric shock.
The eventual cause was determined to be the potential between the
railway 'earth' (the rails) and the station's 240v mains 'earth' at it's
electrical switchboard. They were quite different.