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maintenance director
neutral grounding @ pole??

Just scrolling through and had a thought. If the drop from power co is grounded @ pole, then there is no need for GEC ground @ ground rod or panel, correct? I have noticed several places {here in wichita** where the thieves have cut the copper running down the pole, this means the neutral is no longer grounded for lightning, etc. Am I correct in my thinking, and why, after several calls and even in person conversations whith power co, has nothing ben done? Shurely this is a hazard. looking forward to all comments, thanks..

JLMCDANIEL
Re: neutral grounding @ pole??

Even though there is a ground at the pole the GEC is still required because there exists ground resistance and the GEC is needed to bring the building ground as close to the local ground potential as possible. Because the PU has multiple grounds along its line, replacing individual grounds is not a high priority. IMHO.

Jack

Re: neutral grounding @ pole??

Maintenance director, you're stepping into an on-running gun battle between the utility and lots of customers.

Not-too-well-known facts are: 1) the 7200V primary neutral on a pole is usually jumpered to the 120/240V secondary so the inherent transformer benefit, isolation is not being utilized. 2) the ground at the pole(s) suffers the same inadequacies as the ground rods at our meters..high resistance. 3) EPRI has stated as much as 60% of the imbalanced current fom a customer returns to the utility through the earth.

IMO, if the utility ground was loose or missing and the customer doesn't have a cold water or Ufer ground (just ground rod(s), walking around your meter in bare feet could get real dangerous.

It's all about money.

Good Luck from Columbiana, Alabama
Maurice Turgeon, http://thesemi-retiredelectrician.com

maintenance director
Re: neutral grounding @ pole??

Thats kinda what I was getting at. The imbalance at the meter box is the only "ground". They just dont care, good ole westar energy, thanks guys, wayne...

keith3267
Re: neutral grounding @ pole??

Maintenance director, are you talking about a single phase circuit at home or a three phase circuit in an industrial location? These are different animals.

Ground potential can vary from place to place, that is why you can't have too many grounds. Also for safety reasons, you can have a voltage drop along your ground wire, if there is a heavy return current on it.

There's a Coast Guard base up in Baltimore that supports a light house off the coast. The cables that go to the light house run down the beach and underwater to the light house. every once in a while, they get a call that the power is out at the lighthouse. Most of the time, they find a fried corpse on the beach with a hacksaw in his hand.

Brad
Re: neutral grounding @ pole??

A 120/240 volt residential service with a proer neutral will function perfectly fine without a grounding electrode system. The grounding electrode system is a safety measure. I am not advocating not having a grounding electrode system but some of the previous posting are at best misleading.

Re: neutral grounding @ pole??

Art. 250.4 of the 2011 NEC seems to think grounding is more than just safety:
(A) Grounded Systems.

(1) Electrical System Grounding. Electrical systems that are grounded shall be connected to earth in a manner that will limit the voltage imposed by lightning, line surges, or unintentional contact with higher-voltage lines and that will stabilize the voltage to earth during normal operation.

Good Luck from Columbiana,Alabama
Maurice Turgeon,http://thesemi-retiredelectrician

motoguy128
Re: neutral grounding @ pole??

Some newer furnace will not ignite without a proper ground. Some electronics are not happy without a good ground. It protects them from static shocks as well.

I still think safety is the major driver. In particular, it allow large amounts of energy to be readily absorbed such as during lightening strikes, transformer failures and such.

The big thing now in the industrial side is paying attention to arc flash ratings and how transformer type/rating effects the maximum energy potential during a ground fault event. I've had a our electrical engineers describe simple breakers as "grenades" because of the potential for then to pretty much explode if closed during a ground fault.

He also described scenarios with fused disconnects where all the switch gear and downstream fuse box could be melted down before the fuses ever opened up.... which is why I'm properly upgrading my panel in the next couple weeks. The PO's just did a quick & cheap fuse box for breaker panel swap. But left the fused disconnect and a downstream fused sub panel. SO basically they mostly wasted their money and I have to tear it out and do it right. They also didn't bother to upgrade to 200 amp service despite having 2 AC units, a electric range, and elec. dryer with all the usual modern appliances.

Brad
Re: neutral grounding @ pole??
The Semi-Retired Electric wrote:

Art. 250.4 of the 2011 NEC seems to think grounding is more than just safety:
(A) Grounded Systems.

(1) Electrical System Grounding. Electrical systems that are grounded shall be connected to earth in a manner that will limit the voltage imposed by lightning, line surges, or unintentional contact with higher-voltage lines and that will stabilize the voltage to earth during normal operation.

Good Luck from Columbiana,Alabama
Maurice Turgeon,http://thesemi-retiredelectrician

How is that not a part of safety?

Re: neutral grounding @ pole??

(1) Electrical System Grounding. Electrical systems that are grounded shall be connected to earth in a manner that will limit the voltage imposed by lightning, line surges, or unintentional contact with higher-voltage lines and that will stabilize the voltage to earth during normal operation.

How are the items above not part of safety?

IMO Limiting line surges and stabilizing the voltage to earth during normal operation are not safety issues.

Good Luck from Columbiana, Alabama
Maurice Turgeon, http://thesemi-retiredelectrician.com

meternerd
Re: neutral grounding @ pole??

Here's an opinion from an electrical utility tech. The pole ground and the grounded neutral are there to clear a ground fault AT THE TRANSFORMER. A ground fault needs to have a low impedance path back to neutral to blow a primary (7200) fuse. It has nothing at all to do with the GEC and bonding at the service entrance panel. If no local GEC/Bonding system exists, any ground fault of the customer equipment could create a difference in potential between the customer equipment and ground due to the high resistance path back to the pole ground. This has caused more than one fatality. The ground rod itself is there to reduce the effects of lightning or other possible high voltage faults. Bonding 1s there to reduce differences in potential between grouded components during a ground fault. The main bonding jumper at the service disconnect assures that any ground faults on a branch circuit will have a sufficient current level to trip the associated breaker. Just my humble opinion.

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