Does other areas hydro vac the utility crossings to expose (pothole) them before directional drilling?
In this case the utility mains and telephone were marked out. I think the cable marker missed the roadcrossing. Quite often an area of 1 km on both sides of the road has to be marked at out at once, which is quite a big task. The UG drawings should be used as well by the drill contractor too to confirm prior to drilling. These drawings sometimes have errors in them too, and a cable gets hit.
Could this fault have produced a "Step Voltage" hazard on the ground around it in wet conditions ?
Good point KIWI, In this case it's a 3Ø400 Volts mains cable. At a depth of 600 mm there is some chance of a step voltage although it depends upon ground resistivity which is even in wet conditions quite high.
Bear in mind all the LV faults 'cooking' away and have not been marked out yet or haven't caused any phase loss yet.
I have not heard of any one being 'zapped' by a faulty cable below ground yet.
In case of HT it's a different scenario.
These cables have an earthed screen around the cable which will take the fault current and trip the earth fault relay.
For a brief period, during the fault, there will be a rise in potential at the fault area, although most will taken back to earth through the cable screen. These faults usually don't cook for days and blow out instantly.
edited for typo errors
[This message has been edited by RODALCO (edited 03-14-2006).]
