Electric shore line connections

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  #1  
Old 05-13-04, 09:00 AM
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Electric shore line connections

If you have questions involving electric shore lines I will be happy to answer them. Please post your question here and send me a private message so I can answer you promptly.
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Tom Horne
 
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  #2  
Old 05-16-04, 10:23 PM
Join Date: Dec 1999
Location: Northeastern NC On The Albemarle Sound
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Private Boathouse

Tom,
I built a 150' pier, dock and two-story (upper deck) boathouse in 1995. I wired it myself and there was no inspection required in this rural county back then. Isabel hammered it last year (pier and dock gone, boathouse intact), and I'm going to re-build it soon, but the county now requires an electrical inspection.
The 1995 electrical that I did for it consisted of:
A. A 20 amp GFCI breaker in the panel in my home,
B. 250' of 8/3wg UL most of the way out with 56' additional 10/3 from a j-box under the pier to a breaker box in the boathouse (306' total from panel to breaker box),
C. From the breaker box (C, D & E), 240v to the boatlift control switch and to the lift motor (wiring that came with lift),
D. A 12/2 wg 120v circuit for interior and exterior lights, and
E. A 12/2 wg 120v receptacle circuit (upstairs and downstairs).
Piers get a little racked up and out of shape due to ice or storm water, so I did not use any conduit (VERY few do here until now) to allow greater flexibility in the loosely layed wire under the pier from the bulkhead out to the boathouse. (The wiring is buried from the house to the bulkhead, but not as deep as code requires and not in conduit).
This boathouse electrical system worked great, but would trip the GFCI breaker once in a while in very heavy fog or due to a nearby lightning strike. That was no problem with me, since I would rather it trip the breaker than 240v through me in an aluminum pontoon boat hanging in the water in a steel frame lift with steel cables.
All of the original 8/3 and 10/3 wiring came apart at the j-box when the pier was swept away, but all of the 8/3 is still through the bulkhead and the 10/3 is still attached to the breaker box in the boathouse. I've just coiled them up. The 12/2 is still intact in the boathouse, also.
I know that I will have to put everything from the bulkhead to (and in) the boathouse in conduit now, and I'm going to mix some flex conduit (pier flexibility) and rigid conduit.
Do you have any suggestions about how it is wired other than how I did it originally (which is still my plan, unless I'm told differently). Thank you!
Mike
 
  #3  
Old 05-17-04, 06:54 AM
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Originally Posted by Mike Swearingen
Tom,
I built a 150' pier, dock and two-story (upper deck) boathouse in 1995. I wired it myself and there was no inspection required in this rural county back then. Isabel hammered it last year (pier and dock gone, boathouse intact), and I'm going to re-build it soon, but the county now requires an electrical inspection.
The 1995 electrical that I did for it consisted of:
A. A 20 amp GFCI breaker in the panel in my home,
Is this a two pole GFCI breaker?
B. 250' of 8/3wg UL most of the way out with 56' additional 10/3 from a j-box under the pier to a breaker box in the boathouse (306' total from panel to breaker box),
Are both cables Copper? How deep is the 8/3 actually buried. Did you mean type UF cable when you said UL? What is the size and amperage of the lift motor? How many lights are there in the boat house and on the pier? Does the boat have a shore line to supply electric power to it? Have you checked with the inspector's office to see if you will need to rerun the underground portion of the feeder? If any portion of it has become exposed you don't need to check, just reconcile yourself to digging new trench and rebury it. Are you certain your inspector is going to require conduit under the pier?
C. From the breaker box (C, D & E), 240v to the boat lift control switch and to the lift motor (wiring that came with lift),
Are the letters from a sketch?
D. A 12/2 wg 120v circuit for interior and exterior lights, and
E. A 12/2 wg 120v receptacle circuit (upstairs and downstairs).
Piers get a little racked up and out of shape due to ice or storm water, so I did not use any conduit (VERY few do here until now) to allow greater flexibility in the loosely laid wire under the pier from the bulkhead out to the boathouse. (The wiring is buried from the house to the bulkhead, but not as deep as code requires and not in conduit).
This boathouse electrical system worked great, but would trip the GFCI breaker once in a while in very heavy fog or due to a nearby lightning strike. That was no problem with me, since I would rather it trip the breaker than 240v through me in an aluminum pontoon boat hanging in the water in a steel frame lift with steel cables.
The nuisance tripping of the GFCI breaker can be eliminated by relocating it and this can also make resetting it a hell of a lot easier. Are there any power outlets or lights on the pier itself.
All of the original 8/3 and 10/3 wiring came apart at the j-box when the pier was swept away, but all of the 8/3 is still through the bulkhead and the 10/3 is still attached to the breaker box in the boathouse. I've just coiled them up. The 12/2 is still intact in the boathouse, also.
I know that I will have to put everything from the bulkhead to (and in) the boathouse in conduit now, and I'm going to mix some flex conduit (pier flexibility) and rigid conduit.
Do you have any suggestions about how it is wired other than how I did it originally (which is still my plan, unless I'm told differently). Thank you!
Mike
My biggest concerns are grounding and bonding at the boat house and the voltage drop in that long a feeder. Once you provide information on the loads to be served I can do a voltage drop calculation to determine if you are beating the lift motor to death with under voltage starting.
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Tom Horne
 
  #4  
Old 05-17-04, 08:01 AM
Join Date: Dec 1999
Location: Northeastern NC On The Albemarle Sound
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1. Yes, it is a two-pole 20 amp GFCI breaker.
2. Yes, all copper, and underground cable.
3. The 8/3 is buried from 6"-24".
4. The 3/4 hp motor (6.5 amps for 220v) came with the 3,000-lb boatlift. It can be 110v or 220v, depending upon distance. I have run it wired both ways, and it works fine either way, but I use 220v. The manufacturer recommends # 10 wire for up to 320' for 220v, and #8 for up to 500'. There is 306' between the panel and the motor.
5. There is a 100w light inside the boathouse and a rarely-used double 150w floods fixture on the outside of the boathouse.
6. There is a 110v receptacle inside the boathouse for running a 12v battery charger or a 110v vacuum cleaner, and there is a never-used 110v receptacle upstairs at the overhead deck level. There are no outlets or lights other than at the boathouse itself.
7. I haven't discussed the buried part of the line with the local inspector. He did say that the exposed line under the pier and in the boathouse would have to be put into conduit, although most don't have it that way now.
8. C,D & E were the letters in my original post for the lift motor and the two 110v circuits wired from the breaker box.
9. The breaker rarely trips except in extremely heavy moisture (heavy fog) or a nearby lightning strike. I like having the whole thing on a GFCI from the panel out, and I don't mind a rare walk back to the house to reset it, if I happen to get out there and it's tripped.
10. Everything is in the boathouse. There are no lights or receptacles on the pier.
11. The 8/3 is grounded at the ground bar in the panel. The grounds at the breaker box in the boathouse (220v and 110v) are connected to this single ground. Both hot legs go to the motor, and the two 110v circuits are split one hot each and both to the neutral.
All of this has worked great for more than 8 years (until "HELLO Isabel").
Thank you for your help!
Mike
 
  #5  
Old 05-17-04, 09:40 AM
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The code permits twenty ampere circuits on residential property to be buried 12" deep if it is protected by a GFCI.

It sounds like you have the voltage drop problem whipped. The loads you describe should be fine on the existing feeder.

The grounding at the boat house panel is still unclear to me. Are there two separate buss bars in the boat house panel with one for the neutrals and one for the Equipment Grounding Conductors (EGCs) or do the neutral and the EGC of the feeder circuit both terminate on the same buss bar?
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Tom Horne
 
  #6  
Old 05-17-04, 11:07 AM
Join Date: Dec 1999
Location: Northeastern NC On The Albemarle Sound
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Tom,
I'm going to have to answer the "grounding at the boathouse panel" question when I can get time to wade out to the boathouse with a ladder and actually look. To tell you the truth, I simply don't remember exactly how I did it in 1995 now.
I think that all of the grounds go to a ground bar, and the two 110v neutrals and the neutral from the panel go to a neutral bar there. All that I know is that it has always worked fine "as-is". I'll get back to you on it. Thank you for your help. Mike
 
  #7  
Old 05-17-04, 11:12 PM
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No Need For Wading.

Is the body of water involved here fresh, salt, or brackish?

I take it from the wading comment that the boat house is now cut off from the land by the loss of the pier. You don't need to go wading out there to answer the question as you will know the answer soon enough without that. If there are separate buss bars then all is well. If not then you should purchase and install an additional buss bar for the boat house panel. The add on buss bar will install directly to the cabinet of the boat house panel. The mounting screws will bond it to the cabinet. Remove any screw or strap that bonds the neutral buss bar to the cabinet of the boat house panel. Make sure that the neutrals and EGCs are not cross connected in the feeder supplied boat house panel. The EGCs should terminate on the bonded buss bar. The neutrals should terminate on an insulated buss bar that is not bonded to the panels encloure cabinet.

Since the pier and boat house is a structure it should have a disconnecting means.
225.31 Disconnecting Means.
Means shall be provided for disconnecting all ungrounded conductors that supply or pass through the building or structure.
225.32 Location.
The disconnecting means shall be installed either inside or outside of the building or structure served or where the conductors pass through the building or structure. The disconnecting means shall be at a readily accessible location nearest the point of entrance of the conductors. For the purposes of this section, the requirements in 230.6 shall be permitted to be utilized.
Check with the inspector in advance to find out if a disconnecting means will be required at the bulkhead end of the pier. If yes you would install a suitable breaker enclosure and breaker at the bulkhead end of the pier as your structure disconnecting means.

The structures grounding electrode system would be installed at that point. The Grounding Electrode System would consist of two driven rods that would be driven at least ten feet back from the bulkhead and at least six feet apart. Installing the rods ten or more feet apart is best practice. You can rent a demolition hammer with a ground rod cup to drive the rods at any good tool rental outlet. Although not required the best practice is to drive stacked rods by using ground rod couplers. You will have to order the couplers on line or from an electrical supply house. The idea is to drive the ground rods deep enough to be below permanent moisture level. A single rod that has an impedance to earth of twenty five ohms or less is all the code would require but since you have not the means to measure the impedance you will need to drive a second rod in order to satisfy the inspector. The first rod would be stacked until you have three coupled rods buried or until you strike rock bottom. The second rod is window dressing so one section is enough. Use the copper clad rods. Two single rods would meet the code but the stacked rod sections will provide a much more effective grounding electrode. The structure disconnecting means enclosure would also be a great place to install a supplemental surge arrester such as the ones shown here. http://www.deltala.com/prod01.htm You would want the LA302G. It has two black leads, one green lead and one white lead. This will provide considerable protection to the wiring on the pier against the voltages induced by nearby lightning strikes.

The GFCI breaker satisfies all of the requirements for ground fault protection of personnel for the pier and the boat house.
210.8 Ground-Fault Circuit-Interrupter Protection for Personnel.
(A) Dwelling Units. All 125-volt, single-phase, 15- and 20-ampere receptacles installed in the locations specified in (1) through (8) shall have ground-fault circuit-interrupter protection for personnel.
(8) Boathouses
215.9 Ground-Fault Circuit-Interrupter Protection for Personnel.
Feeders supplying 15- and 20-ampere receptacle branch circuits shall be permitted to be protected by a ground-fault circuit interrupter in lieu of the provisions for such interrupters as specified in 210.8 and Article 527.
If I can be of any more assistance please let me know.
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Tom Horne
 
  #8  
Old 05-18-04, 12:45 AM
Join Date: Dec 1999
Location: Northeastern NC On The Albemarle Sound
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Tom,
Thank you very much for all of your time. I'm going to meet with the local County Building Inspector to see what they require (in light of all of your great information), and go from there.
(The Albemarle Sound, BTW, is primarily considered "fresh water", but it gets brackish on the inland end in periods of low rainfall, and is salty of course on the east end near the Atlantic behind the northern NC Outer Banks.)
Thanks again.
Mike
 
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