Thanks guys to get some replies already, especially over Christmas.
Here in NZ when the SL's fail for whatever reasons, there is usually a lot of noise from locals who complain about security which is fair enough. Still a pity that SL ccts are often a afterthought and the cabling is put in afterwards and not at the same time when the area was recticulated.
The POCO's are slack in regard with providing schematics in transformers.
Lack of section fuses is an other problem.
some ccts may have 6 or 7 different branch offs all connected to the SL busbar. One fault and all is out. At least with fuses you limit the area in darkness.
One of my workmates said "you can't rewire the poco, just go with the flow".
With the pilot system, if one string fails , everything downstream of the cct is off. ok there is a visual indication at night what is out , sometimes quite a large area, a temp fix is done. e.g. 24 hour the lights till there is time to sort out the problem / locate and isolate the faulty circuit.
I can see that the lightcell has it's advantages for each pole although it's not done in the city, mainly because POCO's like to see the lights come on in bulk at the same time instead of scattered all over the place.
They don't seem to worry too much over the inrushcurrent, Amagine 10,000 SON' lamps 150 Watts all striking at the same time on one circuit from a sub cct.
Most lamps in NZ are 80 / 150 or 250 Watts SON. SOX are extinct in Auckland, some in industrial areas but because of colour rendering they have been phased out over the last 15 years. They used to have a great life span I recall. around 15,000 hrs.
Enjoy your x-mas break if you have one.
