This photo was taken in the Southern California area and it shows a 4800 volt overhead to underground utility transition. The conduit was hit by a car, that damaged the conduit and deflected the lead covered conductors.
Luckily for the car, it would appear that the cable sheath did not rupture. This condition has existed for many months since the damage.
Posted via Joe Tedesco
[This message has been edited by Webmaster (edited 08-30-2001).]
Joe, Certainly a crime, and violation of both NEC and NESC. Maybe one of the best reasons you see for PVC though. If that had been steel crushed like that, it likely would not have survived. Also, steel tends to go away after a number of years (at least in our soil) so there goes any "bonding" effects.
Re: Broken Conduit on 4800 Volt Utility Line#112732 08/31/0104:02 PM08/31/0104:02 PM
i know fpl always fixes problems like that real fast.. paper and lead cable is extremely durable and reliable.. better than poly cable for the same thing... what is disturbing to me is in the lower pictures, theres no switches or fuses from that over head to underground... if one of those underground cables faulted, it would probibly take out the whole feeder back at the substation... ever seen a 65 amp fuse at 13,000 volts blow as the guy on the bucket closes the switch? very loud and firey
Remember when you read my posts, im only 17, still learning... "Hey, its takes what it takes!"
Re: Broken Conduit on 4800 Volt Utility Line#112736 08/31/0111:26 PM08/31/0111:26 PM
Good eye, Merrit, I did not pick up the lack of fuses, and I've been the dunderhead in the rain closing the switch!!!!. Locally, the power companies went through a phase where they were getting rid of company lineman and contracting out, this got rid of the most valuable resource they could have. It is taking MUCH longer for them to respond to this thing. I was Chief Lineman at a prison a few years ago, and could call the utility when I came across a serious problem with one of their poles and they responded immediately. Saw a buck arm pole at the airport with the top completely shredded, called them 25 days ago, and still damaged. Been working nights, Joe, will get a pic if it is not replaced next daytime shift.
Re: Broken Conduit on 4800 Volt Utility Line#112737 09/01/0105:11 PM09/01/0105:11 PM
Originally posted by George Corron: Joe, Maybe one of the best reasons you see for PVC though. If that had been steel crushed like that, it likely would not have survived.
Is there a consensus that pvc is better for HV installations??
I have seen many drops just like the one shown. My opinion has always been that rigid steel would be better because of the additional impact protection it provides. I'm willing to reconsider if someone can convince me.
Not that it really matters what I (we?) think. The PoCo will do what they want here.
[This message has been edited by golf junkie (edited 09-01-2001).]
Re: Broken Conduit on 4800 Volt Utility Line#112738 09/01/0106:16 PM09/01/0106:16 PM
OK, here are my reasons for PVC. I've installed, and repaired both, and had to completely repull the cables because a piece of "rigid" steel (that rusts right at ground level where the water gathers after a few years) was sharp as hell where it rusted and cut the cable. The ensuing fire/sparks/fault were extremely dangerous to the public, and guy who hit the pole. Just back into it? OK, if the angle is right MAYBE the rigid won't crush into the cable...MAYBE. Of course, it it is rusted, that ain't gonna happen, it's gonna crush and here we go through the fault routine again. Now lets repair. We have to have a major outage to replace rigid, in this area we use a pvc "cover" to enclose most of these conductors (and NOT on the street side, there were several design errors noted on this install that would not pass muster here) and it replaces quickly. The cover is sold by AB Chance if you guys wanna see it, and is extremely strong, you can also purchase metal. In case of a fault no one can detemine in hole fault can go on for some time, the PVC will not conduct it into some innocent passerby. Anyway, not trying to convince you, just stating my reasons that steel does not get past my design criteria. Low voltage anyone ????