Hypothetical Light pole.

[ryan_618]

Re: Hypothetical Light pole.

Bennie: I would be willing to bet that if there was an EGC conductor at the poles, it is probably undersized. A typical installation of a light pole includes upsizing the phase conductors to compensate voltage drop. The problem occurs when 250.122(B) is not followed, and an undersized EGC is installed. You talked about using the conduit as an EGC, and I have no problem with that, but given the potential lenght of the circuit, I wonder what the impedance of the metal raceway is? You can't tell me that having a properly sized EGC would not be better than a metal raceway going a long distance.

 

[bennie]

Re: Hypothetical Light pole.

Ryan: I am saying neither method is any sure system. Both techniqes are subject to changes to the point they are inoperative.

 

[iwire]

Re: Hypothetical Light pole.

I think you may be setting your daughter up for a law suit. :roll:

 

[bennie]

Re: Hypothetical Light pole.

No Bob, I am preventing a law suit. Minimum code compliance is a lawyers Mercedes Benz.

My daughter was sued for a fatality, when a 13 year old girl ran her rental ski doo into another skier. The State law is no one under 18 can ride these toys. My daughter was sued for 10 millon.She prevailed, but it put her out of the water sports rental business.

One can observe all the rules, and still go down. I lost a lawsuit from an airplane crashing into my ditch digger.

Lawyers always bring in expert witnesses to find out if more can be done to prevent accidents. They win each time.

Isolation and insulation are the closest procedure to permanent assured safety. The rest are band aids, for commercial interest.

 

[don_resqcapt19]

Re: Hypothetical Light pole.

Bennie,

Stating that a rod beside a light pole into the water table is a waste, is highly irresponsible.

I don't understand how the ground rod is going to be more effective than an EGC. Both are subject to failure. Can you explain why the ground rod is better than the EGC?
Also in terms of the legal issues, I'd be careful of insulating the poles. If there is still an accident, a good attorney will twist that around and say that you knew there was a potential problem and did not take enough steps to prevent it. Just the fact that you have installed the insulation indicates that you knew there is a problem and can increase the liability. Sometimes ignorance is a legal defense that stands up in civil suits.
Don

 

[dereckbc]

Re: Hypothetical Light pole.

Originally posted by ryan_618:
Regardless of frequency, the existing grounding electrode system of the structure+the impedance of the EGC would still be lower impedance than a driven rod, right?

Not at high frequencies. That is where the confusion begins. NEC domain is power frequencies DC-to-400 Hz) or safety. Performance is above the power of safety range.

For example; What is the impedance to an earth ground electrode of 25 ohms of a #6 AWG and 750 MCM cable, 100 feet long @ 10 Mhz in free air? I will check back later.

[ May 10, 2004, 10:15 AM: Message edited by: dereckbc ]

 

[bennie]

Re: Hypothetical Light pole.

Don: I may be misleading. I do not maintain that an ground fault conductor is not a good concept. I feel it is only a quick (feel good) possible fix to a potental lethal problem.

A $3.98 circuit breaker made in South Tijuana is not my idea of protecting my grandson.

How many have heard that death rattle of a dead line short, or ground fault. I have had to physically open the breaker to clear the rattle.

Very embassasing when Bill Gates is watching

[ May 10, 2004, 11:29 AM: Message edited by: bennie ]

 

[ryan_618]

Re: Hypothetical Light pole.

Bennie: I agree with your statement regarding circuit breaker failure. How does a ground rod placed at a light pole remedy such problem though?

 

[don_resqcapt19]

Re: Hypothetical Light pole.

Bennie,

I may be misleading. I do not maintain that an ground fault conductor is not a good concept. I feel it is only a quick (feel good) possible fix to a potental lethal problem.

I think that the best possible solution to the safety problem of remote light poles is a combination of a code compliant EGC, a grounding electrode for small poles or the concrete base and rebar where the base is at least 6' deep and 24" in diameter, along with a GFCI device in addition to or as part of the normal OCPD.
don

 

[Guest]

Re: Hypothetical Light pole.

Maybe Bennie has an objection to the $13.98 GFCI circuit breaker hecho en honduras?

 

[iwire]

Re: Hypothetical Light pole.

Bennie I was to blunt in my earlier post, of course you want the best for your daughter.

My thought was much along the line of Don's post.

If an accident happens now it will be shown that someone, in this case with a professional electrical background was aware of a problem but never brought the installation into code compliance.

I agree, you are right, 100% code compliance will not stop all possible suits, at the same time lack of code compliance will be tough to defend.

IMO make the grounding system work and comply with todays code.

Then plastic coat away,

Bob

 

[tom baker]

Re: Hypothetical Light pole.

Hadco (street light mfg) makes a steel pole that has a polyethelyne sleeve that is colored and decrotative that slides over it. Can't be damaged by cars and is non conductive.

 

[brentp]

Re: Hypothetical Light pole.

Double insulating a light pole sounds like a good idea to me.

 

[bennie]

Re: Hypothetical Light pole.

My daughter is also planning a 3 story office building on the same property. If my health holds up, I will be the owner's inspector.

Any problems develop, I will share, in hopes of free information.

 

[jschultz]

Re: Hypothetical Light pole.

http://www.mikeholt.com/codeforum/ultimatebb.php?ubb=get_topic;f=7;t=000095#000003

is this the previous thread on this subject?

 

[iwire]

Re: Hypothetical Light pole.

No, not the one that has been removed, it is gone for good.

 

[dereckbc]

Re: Hypothetical Light pole.

Originally posted by iwire:
No, not the one that has been removed, it is gone for good.

It is not gone for good, it has just been moved where you can't see it. Blame me, I moved it.

 

[iwire]

Re: Hypothetical Light pole.

Originally posted by dereckbc:
it has just been moved where you can't see it. Blame me, I moved it.

No blame, probably a good move.