Ideal dock wiring Questions?

Discussion in 'Electrical Forum discussion & Blog' started by Randyj, Mar 20, 2011.

1. ballvalveGeneral Engineering Contractor

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Dec 28, 2009
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"retired" and still building and troubleshooting
Location:
northfork, california
This company has a help line and understands EPB grids, so the OP might learn and buy something that helps his dock issues...

Go back to page one, I think, and I posted a link with great detail about cows and stray currents.

http://www.diychatroom.com/f18/proper-wiring-outlets-dock-near-water-43766/

Go there and scroll down about 5 posts. Someone posted a very specific wiring diagram/drawing on how to do a dock correctly.

Last edited by a moderator: Mar 27, 2011
2. RandyjMaster Plumber

Joined:
Nov 25, 2006
Location:
Alabama
JW... one or both of us is hard headed or dumb as a rock. First of all I never said anything about the dock or earth or water having an imbalance. I said the dock becomes balanced with the earth ground. And, yes I understand the role this could play as a lightning rod function.

Since you asked the question of what role I think the ground rod plays in an electrical circuit... let me ask you.. what role does a grounding rod play in a circuit if it is bonded to a switch box panel, transformer, or whatever it may be attached to?

I do understand that if a hot wire contacts a metal dock the dock and thus the earth becomes energized. It is the ground rod that conveys this potential energy to the earth. This is where the circuit is no longer in the neutral wire but the dock and it's ground wire becomes the circuit in question. I also understand that the "safety ground" is the ideal way to return the electricity to the switch box panel.. which would then convey it to the earth ground or neutral if the neutral is bonded to the ground wire. This is why I asked the question which you did not answer "should the neutral be bonded to the "safety ground/earth ground" at the dock so the electricity can return to it's source? I totally understand that the earth is like a huge resistor and there will be an electrical gradient around an energized dock. However, if a dock is isolated and is charged and you are standing on the dirt or in water and grab that dock then you're gonna get a big jolt of electricity. If you have that dock attached to a ground rod then you are not going to receive the full force of that shock. I would say that this is analogous to not contacting any kind of conductor and grabbing the hot wire and not feeling even a tingle.

One thing I remember from my childhood was reading a story in Reader's Digest of how this person was writhing on the ground which was charged with thousands of volts of electricity from a downed power line. This is analogous to what you are describing.

What I'm trying to figure out is how to safely get rid of that Tickle/ants in the pants when the ground wire from the box with a door on it which is hundreds of feet away is attached to the dock. I already know why it exists which is something you seem to be overlooking. This is the equipotential ground you started out talking about... but apparently this does not remove the ants.

Last edited: Mar 26, 2011
3. RandyjMaster Plumber

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Nov 25, 2006
Location:
Alabama
P.S. Since we are talking about returning the electricity to it's source via the neutral and that earth ground (the little green wire many people hate which attaches to the center of a 120 volt receptacle)... In a residential application you have one or two hot wires and a neutral coming from a transformer to the switch box panel whether they come through the air or under ground. An earth ground is attached to that enclosure. This switch box becomes the source for the branch circuits. When a switch box panel is mounted on a dock does it not become the source of the branch circuits on that dock?... same as a switch box panel at a house? Would the ground rod at the dock entrance not perform the very exact same function as that ground rod bonded to the enclosure back up at the lake house hundreds of feet away?

I have NEVER seen a light bulb or receptacle wired directly to a transformer on a pole....

Last edited: Mar 26, 2011
4. jadnashuaRetired Defense Industry Engineer xxx

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Retired Systems engineer for defense industry.
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New England
And, I think you're still missing the point...the earth ground does not normally carry ANY current - it is there as an emergency, alternate path to trip the safety circuits - i.e., the breaker. The current returns via the neutral.

The ground and the ground rod are there to dissipate stray power that may come in via some outside source (biggest one is a nearby lightning strike).

5. RandyjMaster Plumber

Joined:
Nov 25, 2006
Location:
Alabama
Jim... you are exactly right and I have totally understood and agreed with that from the beginning. The earth ground is not to be substituted for neutral. There is not, never was, nor ever has been anything in my posts that says that it is. Where the confusion is at is where the service entrance is. I'm saying that the service entrance for the dock is at the switch box on the dock. JW is saying that the service entrance is at the switch box hundreds of feet away at the house... hugely different. The boat dock is a structure. It is NOT.. I repeat NOT... I'll repeat again NOT a piece of equipment.
As for his thing about grounding through a hinge pin... he is just flat totally wrong. It is no more reliable than a rusty greased trailer hitch. If you want to demonstrate this to yourself go hook up your boat trailer that has been sitting outside all winter.. or go rent a U-haul trailer... do not hook up the ground (negative) wire to the trailer. You'll find that the lights will not work properly until you drive around and hit enough bumps to knock out the rust and make very good contact inside that trailer hitch. Same exact deal on walkway hinge/pivot points. A ground rod and bonding jumpers across hinges reinforces this connection. One thing I do know very well is boat dock structure.

What JW is saying, describing, and criticizing about I absolutely and 110% agree with him IF we were discussing wiring a car port within spitting distance of the main switch box at a residence. However, that is absolutely not what is being discussed. JW seems to be totally disregarding the distance from the main switch box which makes this absolutely and totally different from wiring said car port or a room in a residence. He's supposed to be the pro here... I'm the one who isn't supposed to know anything... but I do know about resistance in wires, voltage drops due to the length of wire. His safety measures are absolutely correct but I strongly question the application, not the methods.. can not compare apples and oranges.

Last edited: Mar 26, 2011
6. ActionDaveElectrician

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You don't get it do you? It is you who are comparing apples to oranges. The power company has it's own set of rules. The NEC has it's own set of rules. They are separate for a reason. Ground rods have little to do with making an electrical system safe after it leaves the POCO transformer.

7. jwelectricElectrical Contractor/Instructor

Joined:
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Instructor
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North Carolina
Randy
Letâ€™s keep this simple and to just one circuit. Letâ€™s install a 120 volt 15 amp circuit to this metal dock for a light and receptacle.

In the branch circuit going to that dock will be one black hot, one white grounded neutral, and one bare or green the equipment grounding conductor.

Should the black hot conductor be in contact with the metal dock the current will flow back to the service equipment on the bare green wire at which point it will then cross the main bonding jumper to the neutral at the service equipment and from there back to the transformer.
This current will take this path if there was never a ground rod driven anywhere on the premises.

What this current in this 120 volt circuit will not do is travel to earth in any way. This current will not go to the ground rod that is installed at the service at all. No not even one amp.

Now with your analogy of the rusted trailer hitch just where does this grounded negative wire connect to the ground rod? The trailer hitch is the same as the white wire in a 120 volt circuit or it is the return path back to the battery.
Here is where you are confusing yourself in the thinking that the trailer hitch has a ground wire like the 120 volt circuit which it doesnâ€™t. In the trailer hitch the chassis of the vehicle is the second wire unless there is a negative wire installed instead of the chassis of the car. What the car does not have is a ground rod or even a ground wire.

If you want to drive ground rods at the dock then by all means drive as many as you want. There is no harm in all those rods down there but the second you cut the equipment grounding conductor you need to be prosecuted in court for attempted murder.

Your conception of earth ground is enough to make me wonder just why as a maintenance man they would allow you to even change a light bulb. You are dangerous and what makes you so dangerous is you self-selling idea of earth ground and you inability to listen when someone is trying their best to correct your mistake.

Cutting the equipment grounding conductor at the metal dock is what that I sent to the licensing board down there and I will promise that someone will be cruising those lakes looking for metal docks. When they find one where the equipment grounding conductor has been cut they will be coming after that person with a vengeance.

The ground rod plays absolutely no role in the circuit at all. The circuit will work just fine without a ground rod ever being installed.
The reason we install the rod is in case lightning strikes.

Here is where you seem to understand nothing and are as confused as a cat caught up in a dog kennel.
Current is not conveyed to the ground rod. Current is conveyed back to the transformer from which it came.
Here is where you refuse to listen and are making a critical life threating mistake that someone somehow must stop.

The only place that the neutral and the grounding electrode conductor, equipment grounding conductor, or any metal can come in contact with each other is at the service equipment even if this service equipment is 300 yards away. ONLY IN THE SERVICE EQUIPMENT

Try going around that lake and repairing all the installations done by maintenance men and do away with those that persist in doing something different than what several thousand engineers have been doing for the past 100 plus years to make the electrical installations safe then maybe just maybe the ants in the pants will go away. Wonder why there is so much effort put into writing the NEC if all the information contained therein is so damn wrong?

8. jwelectricElectrical Contractor/Instructor

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Notice the wiring diagram posted by ballvalve.

From the service disconnect to the panel at the pier there must be an insulated equipment grounding conductor installed that bonds to the required ground rod installed at the dock panel.
This ground rod is required because there is more than one branch circuit that supplies the pier and it must be a four wire feeder, two hots, grounded neutral, and equipment grounding conductor that is not to be cut for any reason.

Notice that every pivot point on this metal dock is bonded around using a #8 copper conductor. Care must be taken should this metal dock be made with aluminum or an aluminum alloy as the connection will not last very long if not done correctly.

All metal of this dock is bonded back to the panel that supplies the dock where the insulated equipment grounding conductor is also bonded. Should the metal dock be energized by one of the circuits supplying the metal dock the current would be carried back to the service equipment at the house and on to the transformer supplying the system causing a large amount of current to flow tripping the breaker.
This would work if there was no ground rod installed either at the house or the dock. The ground rods at both the house and the dock plays no role what so ever in clearing the hot that touches the metal dock. The ground rods will give lighting somewhere to go but it sure won’t do anything to clear any other current.

9. RandyjMaster Plumber

Joined:
Nov 25, 2006
Location:
Alabama
JW.. I don't know why you insist on me being confused when I constantly say that I agree and understand your methods. You try to say that I'm calling a trailer hitch an earth ground when that is absolutely the farthest thing from the truth. I am describing it as a CONNECTION... NOT as an earth ground. You are trying to make me appear as an idiot. By your own statements you totally contradict yourself saying how a ground wire dissipates a fault to the earth if a neutral wire is broken.
If a metal dock is all that exists on the property.. just like a metal building anywhere on earth. Would you wire it to a switch box panel hundreds of feet away? It is not at all that I am challenging what you are saying. I am trying to understand why there would be a difference.

Last edited: Mar 27, 2011
10. RandyjMaster Plumber

Joined:
Nov 25, 2006
Location:
Alabama
I have asked time and again about what you would do to remove the tickle/ants in pants. The only thing I've seen that appears to be a solution to do this is the drawing just posted by ballvalve which does in fact satisfy what I've been saying AND what you've been saying. It shows the ground rod being at the dock connection (which is not mounted on the dock) and the equipment ground connecting to that AND the switch box panel at the house. IMO, the proper solution and one that would work is for tight wads to purchase wire which is heavy enough that it won't have a voltage drop. I've seen many old docks served by a 12 gauge wire which is run several hundred feet when they should have very large #6 or #8 wire depending on load. In fact Alabama Power does cruise this lake looking for any safety issue. They are constantly reminding people to use safe practices and when the vacation season approaches they usually send a flyer concerning these issues with their power bills. I'm quite sure they are and have been very well aware of these issues. At the newer high dollar homes on this lake I see some very impressive wiring. The wires to their docks are always big, deep in the ground in conduit, and have a breaker at the dock entrance. The ground wire also runs all the way back to their service switch box. I do not doubt that it is the people who don't want to pay to have their docks properly rewired, to have a sufficient size of wire who are experiencing this problem. In general, it is not at all the wiring on the dock which is the problem but the wires going to the dock. Every time I've been asked about dock wiring and seen a small wire (10-12 gauge) I've commented to the property owner that it may not be sufficient wire size for it's intended purpose. There are far too many legal issues and too much liability for me to attempt to install service to these docks. As a maintenance person my job is pretty much limited to changing light bulbs and replacing receptacles or switches.... same as any home owner is allowed to do. As I said before, a good maintenance man knows when to call in a person professional/licensed in their field.

Last edited: Mar 27, 2011

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Those same tight wads probably have an old transformerless TV out on the dock that they filed down the polarized plug on it in order to plug it into an old extension cord that isn't polarized. Then they wonder why they get a shock everytime they touch the rabbit ear antenna. Now there's a 50% chance they would get a tingle and a 50% chance they would get a big jolt not factoring the resistance to ground!

12. jwelectricElectrical Contractor/Instructor

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North Carolina
If the neutral is broken the circuit will do the same thing that would happen if you open a switch. It would simply stop working. In the event of a fault from the hot and the metal dock or building if the equipment grounding conductor is cut then the only path back to the service would be through earth and the resistance would be so high that the breaker would not trip.

If I was pulling one 120 volt circuit to the metal dock or metal building then I would not install a ground rod. If I were installing a feeder to a panel located at either the metal or wooden dock or a metal or wooden building I would install a grounding electrode system to dissipate lightning and for no other reason.

No I am not trying to make you look like an idiot you are doing a fine job at this yourself.

And I have answered your question time and time again. INSTALL AN EQUIPOTENTIAL BONDING GRID.
682.33 Equipotential Planes and Bonding of Equipotential Planes. An equipotential plane shall be installed where required in this section to mitigate step and touch voltages at electrical equipment.

Equipotential Plane. An area where wire mesh or other conductive elements are on, embedded in, or placed under the walk surface within 75 mm (3 in.), bonded to all metal structures and fixed nonelectrical equipment that may become energized, and connected to the electrical grounding system to prevent a difference in voltage from developing within the plane.

Once again the ground rod installed at the disconnect at the dock and at the house does nothing to remove any type of touch potential. These ground rods are installed in the event of lightning, a higher voltage line that comes in contact with the circuit supplying the house or dock, in case a upstream transformer shorts from primary to secondary, and to keep the voltages stable that are supplying the home or dock. These rods are not installed to remove the shock hazards that you mention nor will they do anything to remove these shock hazards you mentioned. If they would then why would you be cutting the equipment grounding conductor?
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Voltage drop does not cause these shocks that you mention. A #14 conductor ran to a dock would be plenty large enough for one light and a couple of receptacles at a distance of several hundred feet unless the receptacles were loaded to the max or 15 amps.

Should the wire be too small for the load served the overcurrent device be it fuse or breaker will simply open. The voltage drop will in no way cause someone to feel a shock should they touch the metal dock.

What you can’t do is change devices just like any homeowner for anyone except for yourself. You are not allowed to do this for someone else for a profit unless you have an electrical license.
The laws in your state are the same as they are here

Electrical contracting shall be defined as engaging or offering to engage in the business of installing, maintaining, altering or repairing any electric work, wiring, devices, appliances or equipment. No person, partnership, firm or corporation shall engage, or offer to engage, in the business of electrical contracting within the State of North Carolina without having received a license in the applicable classification described in G.S. 87-43.3 from the State Board of Examiners of Electrical Contractors in compliance with the provisions of this Article, regardless of whether the offer was made or the work was performed by a qualified individual as defined in G.S.87-41.1.

Last edited: Mar 27, 2011
13. RandyjMaster Plumber

Joined:
Nov 25, 2006
Location:
Alabama
I do not disagree with you on this or your assessment of the legalities. However, as a maintenance person for the state of Alabama and the company I worked for I was frequently required to do exactly what you are saying that I am not allowed to do. If this is the case then there's a heck of a lot of people out there violating this very thing.
As for the part where I made the statement about "several boat docks" this is an exageration to make a point just like me changing the names of people to protect the innocent. As in an earlier post I said that I was told this by an Alabama Power Engineer. Actually, the site I referred to mentioned a couple of licensed electricians and Cullman Power linemen and I do believe there was a reference to Alabama power also... not my reference. In fact, I have NEVER posed as a licensed electrician. Until I clarify anything I do concerning electricity I will be discussing this with the Electrical licensing board in Alabama. So, your mission there is well taken.

Now... as to your insistence on shortest distance for a return path to a transformer and the use of the terms "shortest route" and "path of least resistance" what you are saying comes across to me as double-speak. What you are saying sounds deadly and extremely dangerous. You say that electricity does not "leak" and that it does not follow the path of least resistance... yet path of least resistance is the terms used in many books and even several articles posted in this thread. According to what you are saying a person can stand butt naked in wet dirt with salt poured on it and grab a naked hot wire and not get even a tingle. If that wire did not leak electricity through that person then he would not be getting dead.
If that wire was within 6 inches of it's return path and this same person standing in salted wet dirt grabs the naked hot wire then he is the path of least resistance... not the air that is between the wire and the neutral in which the air offers the most resistance.
If nothing else, anything you can do to assist me in becoming a licensed electrician and giving me the best education possible would be greatly appreciated. I am absolutely game for that! If they would take the time I spent working in these departments which do have master electricians as apprentice experience rather than requiring me to be employed by a master electrician then I would have all the qualifications to be licensed.

Last edited: Mar 27, 2011
14. ballvalveGeneral Engineering Contractor

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Dec 28, 2009
Occupation:
"retired" and still building and troubleshooting
Location:
northfork, california
Oh Oh, is this becoming an enforcement-reporting forum too? If I post that I did'nt vent my tub and ran my washer drain to the garden, may I expect a visit from the code locals? [!] And now that I JB welded my water tank, will ASME be out to cuff me?

As to bonding / grounding the floating aluminum docks, it seems Aluminum wire would [should] have to be used rather than copper, lest one build a big battery.

15. RandyjMaster Plumber

Joined:
Nov 25, 2006
Location:
Alabama
JW/Mike... I'm going to do you a huge favor before you have a stroke or heart attack or blow a fuse or sumpin'.... I'm just going to totally quit responding to your posts. I will tell you that this is the internet and people post things that are not entirely and absolutely fact. I'll also tell you totally honestly that you can not, will not and never will find a ground wire to a service that I have personally cut or clipped but you see from the link that I posted that there are several who do practice this means of eliminating this tickle. I will also tell you that I have many contacts in the building trades that I refer electrical work to. As I have implied time and again... I'm crazy as hell but I ain't stupid. If you want to have me prosecuted for replacing a light switch for some little old lady on SSI then have at it!!!!! I'll pay the fine and serve my time for the honor of helping people in need of help. If you want to help me get my electrician's license then we can talk. I was not fortunate enough to get in with those in the know when everyone was grandfathered. I was not grandfathered into plumbing... I actually fulfilled all the requirements and took all the tests and did everything a candidate for plumbing license is required to do today.

Last edited: Mar 27, 2011
16. RandyjMaster Plumber

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Nov 25, 2006
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BV... and don't forget that you can't use dissimilar materials when doing plumbing.. .you can't glue PVC to ABS no matter how good it sticks together!

EXACTLY Terry!

And if an absolute enforcement of every letter of the law was followed then I could not even change a light bulb for my momma if she in turn cooked my dinner....

Last edited: Mar 27, 2011
17. jwelectricElectrical Contractor/Instructor

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Instructor
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North Carolina
I am not trying to be the internet police but I do feel that it is my professional responsibility to let those who have been charged with the safety of the public know when something as you have posted here is taking place on public waters.

As a bona fide employee meaning someone is taking out taxes and paying in your social security then for that company you can do electrical maintenance but what you or anyone else in Alabama cannot do is bid work from home owners and let them buy the permit. This will end up getting you in trouble.

I do hope you seek a better understanding of grounding and bonding from people in the know and forget all this cock and bull you are reading on these discussion boards before someone ends up hurt of even worse dead.

You don’t have to take my word for anything but if you search in the right places I know that the information is out there.

As to your analogy that fellow would be perfectly safe if the utility companies had never grounded their systems in the first place. The simple physics of current flow mandates that in order for current to flow there must be a complete path from the source back to the source so if the utility company didn’t earth ground and we didn’t earth ground then the little fellow could pee on that cable with no harm.

18. RandyjMaster Plumber

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Nov 25, 2006
Location:
Alabama
Oh my goodness... here we go on another tangent.. PERMITS! In my home town not even a home owner can pull an electrical permit. That's why I had to hire an electrician to inspect my switch box installation and pull a permit so the city inspector could give his blessings. However, where I live now is extremely rural, no building codes, no inspectors. Not many contractors are going to come out here for a \$50 or even a \$100 job. Even if it were in the big city not many would walk away from their business to replace an outlet for a few bucks. If they've got the overhead of a good sized business they can't afford the \$100k overhead to do \$50 jobs. If they did it would be a public relations service for them... and still lots of people simply are not going to chunk out \$100-\$200 to have a switch or outlet replaced. If the electrical industry is the way the code implies and as you say then it needs to be changed so the electrical service companies can make money and the little guys doing honest and serious maintenance can do them a favor and take care of the little calls which keep them from making money... if money is the only game they've got. Nobody wants to get in trouble and nobody wants to break the law. If the rules are going to be strict then the laws need to provide for all professions and not force the big ones to be greedy and the little ones and the little customers to starve. If these less fortunate people can't afford the big companies then they will be forced to live in very unsafe conditions because they can't get the much needed repairs.

19. jwelectricElectrical Contractor/Instructor

Joined:
Jun 14, 2007
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Instructor
Location:
North Carolina
Section 34-36-3

Definitions.

The following terms shall have the meanings respectively ascribed to them used in this chapter, for the purposes of this chapter, unless the context clearly requires a different meaning:

(1) BOARD. The Alabama Board of Electrical Contractors.

(2) ELECTRICAL CONTRACTING. Any job or project in the State of Alabama wherein the electrical contractor proposes to bid, install, maintain, alter or repair any electric wiring devices, or equipment.

I didn't write the laws I only try to obey them. Someone who can afford a dock can afford to have it wired properly by a professional electrician
If they can’t afford to have it wired and maintained by a professional electrician then they don’t need the dock in the first place.

20. RandyjMaster Plumber

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Nov 25, 2006
Location:
Alabama
Kewl... don't think I mentioned a dock in that post... I wunner if they got a trailer hitch on their ground rod...LOL... hehehe

Last edited: Mar 28, 2011