another electricution - metal street pole-baltimore!

[charlie tuna]

Re: another electricution - metal street pole-baltimore!

he got burnt--face and arms. the school called me, and i ordered the replacement distribution panel ---it was $12,000.. the next day he came back to the job and wanted to do the work--that took some guts to face that mess---i told the school i had no problem turning it over to him. i think the whole thing had to cost him 25 to 30k!
he was tracing some feeder wires with one of his employees. they were talking on the nextel like walky-talkees. then he got the idea to energize this feeder and his employee could tell these conductors with a tick-tracer. setting his nextel phone down on the top of a breaker as he closed a 800 amp breaker was his big mistake! he found what was left of the nextel battery in the bottom of the burnt out distribution panel! he was lucky to be alive. i have photos---but don't know how to post??????

 

[physis]

Re: another electricution - metal street pole-baltimore!

How did that little plastic phone cause all that? And why didn't that 50 amp fuse blow if the neutral wire blew in half?

There must be more to the story.

 

[charlie tuna]

Re: another electricution - metal street pole-baltimore!

that little 50 amp fuse was on the 13,200 volt primary feeder 400 feet away from the vault. it blew that #1 copper wire in half like it was a small spark!

the service conductors -- parallel 500 mcm cu burnt back into the vault until the spacing at the primary transformer connection points isolated the phase to phase fault. the school asked us to do this job--- it was and still is our oppinion that the work preformed is illegal. they hired a contractor out of the classified section of the newspaper---you know "no job to big or too small" "call brian"...

that little nextel phone has a metal cover plate--thats all it needed to start -- the miswired neutrals caused the damage to be massive!

[ January 06, 2005, 04:58 PM: Message edited by: charlie tuna ]

 

[physis]

Re: another electricution - metal street pole-baltimore!

I'm kind of coming away from this thinking that this catastrophic event was at least in part due to someone elses neglegence and this EC got the whole bill.

 

[petersonra]

Re: another electricution - metal street pole-baltimore!

Originally posted by charlie tuna:
it was and still is our oppinion that the work preformed is illegal. they hired a contractor out of the classified section of the newspaper---you know "no job to big or too small" "call brian"...

when you use the word "illegal" are you suggesting the work is not to code or the proper procedures in letting the contract were not followed?

 

[charlie tuna]

Re: another electricution - metal street pole-baltimore!

the school is made up of five buildings-each having their own emergency generator and transfer switch. these buildings were originally medical labratories and have no windows. it is now a charter elementry school - full of young children.
the generator in the elementry building took a dump -- engine is shot! the generator repair company convinced the school that they could backfeed from the other building's transfer switch to feed the school's emergency power.
it will work provided the vault power goes out and the other building see's a power outage. but if the normal power to the school is lost vis it's main breaker, the generator will not start because normal power would still be available to that building. i dread the thought of 1000 kids stuck in the dark -- there is no emergency lighting other than that supplied by the emergency panel. we have explained this to the administator with no response -- i had even found them a demo generator at half price!!!

 

[pierre]

Re: another electricution - metal street pole-baltimore!

The issue of using "supplementary" grounding at poles is at best controversial (IMO).
There are so many variables that there is no certain answer to any question, unless one is at the effected site during the incident.

Just my opinion (for what it is worth )
1. There are conflicting opinions (studies) as to the effectiveness of the supplementary grounding at light poles.
2. Even if high voltage (utility- 7200 volts or more) were to make contact with the poles, there is no garauntee that the utility's protection will open - again so many variables such as earth resistance, distance to the overcurrent protection, resistance of the made connections, etc...
3. Due to my time of teaching and talking to electricians, I see a large proportion in our industry that do believe the ground fault current will travel through the groundrod and open an OCPD .

As has been mentioned, education is the only real answer to this and other problems in our industry.
As more studies are being instituted, we will have better information to educate ourselves and others. It still amazes me how little education there is and is required in our industry .


I know that I have said this before, hairdressers in NY require training and a certificate and continuing education - electricians only require a boss to work for , if even that!!!

Pierre

 

[hurk27]

Re: another electricution - metal street pole-baltimore!

By Pierre: 2. Even if high voltage (utility- 7200 volts or more) were to make contact with the poles, there is no guarantee that the utility's protection will open - again so many variables such as earth resistance, distance to the overcurrent protection, resistance of the made connections, etc

I agree with that one! We had a brandnew house that was damaged badly from being energized by a primary line that the neutral to the service came into contact with. A truck backing up hit the pole and the neutral dropped and hooked around the primary (7200v) The house only had ground rods (plastic pipe well) and received burn damage in many places plus all electronics were fried ( possible from the lost neutral) and the police was able to call the POCO and have the primaries shut down remotely half the city went out but it saved the house and a child sleeping on the second floor bedroom. The home owner was quick thinking after the primary stopped buzzing indicating it was dead he was able to extinguish all the little fires it started with a hose. They said the sparking and arching was coming from everywhere around the house to earth. And nobody could get into the house to get the child out.

 

[petersonra]

Re: another electricution - metal street pole-baltimore!

Originally posted by charlie tuna:
i dread the thought of 1000 kids stuck in the dark -- there is no emergency lighting other than that supplied by the emergency panel. we have explained this to the administator with no response -- i had even found them a demo generator at half price!!!

Is there any requirement for an emergency generator in a school? I have a hard time believing even with a generator that they would have no emergency lighting at all.

 

[charlie tuna]

Re: another electricution - metal street pole-baltimore!

the school was a labritory where they developed the artificial heart. it has emergency systems in place fed from the emergency generator. no battery backup lighting is installed for this reason. if the "normal power" main breaker feeding the school trips - the generator sensing "normal power" from another building from has no start signal and there will be no (emergency) generator power available at the school's transfer switch.