Lake dock wiring question

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Old 02-06-17, 10:47 AM
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Lake dock wiring question

Hi all, First post, hope you can help!
I have a dock on a lake that needs electrical. The electric run from house to dock is 200 ft. The main panel at the house has a 50 amp single pole QO breaker. #3 thwn hot and neutral (1 each) and a #8 ground in 1 1/4" pvc conduit buried 18" all the way to under the dock then run under dock to the roofed dock boat slip. A boat lift will be installed, power requirements 12 amp 120v for lift motor standard receptacle gfci protected. I will install a 4ft 2 bulb fluorescent wet rated fixture under the roofed area and would like to have 2 or 3 convenience receptacles all GFCI protected. I would like 2- 20amp breakers under the boat house roof, 1 for the boat lift motor and 1 for the light and receptacles. My question is, since 120 volts was all that was run down there how do I get the 2 circuits? An idea I had was to use a 70amp 2 space 120/240 panel and either jumper the main lugs or pigtail the incoming lead and feed both lugs, of course label the box 120 volt only. This will be inspected so it needs to meet code. Pulling another wire would be a monumental task so that is last resort. Thanks
 
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Old 02-06-17, 12:06 PM
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Pulling another wire would be a monumental task so that is last resort.
1" conduit is good for seven #3 so is your problem the number of turns or age of the conduit may have filled it with gunk? The conduit isn't EMT is it?
An idea I had was to use a 70amp 2 space 120/240 panel and either jumper the main lugs or pigtail the incoming lead and feed both lugs
Pigtailing would be necessary unless the lugs were rated for two conductors. National code wise it is not prohibited but whether your AHJ will accept we can't say. You need to ask your inspection office.

What has this been used for up until now? Lights and receptacles would have been a code violation.
 
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Old 02-06-17, 12:34 PM
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Nevermind, ray got it first.

With a 50A feeder breaker, you should already have a panel at the dock. A general-purpose circuit with a breaker greater than 20A is not permitted.

Jumpering the #3 copper to both lugs of the subpanel will require an insulated connector rated for three wires. Polaris brand is one type, but there are others. I would probably just use every other row in the panel and avoid the jumper problem altogether. A panel with more spaces will be cheaper than one Polaris connector.
 
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Old 02-06-17, 01:48 PM
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Thanks for your replies. The conduit is pvc. The 50 amp breaker is for the new setup in question so no violation there, the 50 breaker is not actually installed yet. I could use a larger panel and use every other space but I prefer a small 2 space for a less intrusive tidy install. I'll ask the inspector if he will accept the pigtail using a Polaris connector, I just didn't wanna ask him if it was totally out of the question, thanks again
 
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Old 02-06-17, 02:16 PM
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An idea that just came to mind. If you can find a panel with "feed through lugs", those will provide a convenient spot to install a jumper with no need for an additional connector. I don't know off the top of my head if anyone makes a small 2 space panel with feed through lugs.
 
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Old 02-06-17, 02:19 PM
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Still curious why you say you can't add a wire.
 
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Old 02-08-17, 04:09 AM
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Never heard of feed through lugs, I'll check it out. As far as running another wire in the pvc goes, it's not impossible but will be difficult for two reasons. There is not a pull string left in the pvc and the conduit run has its fair share of turns to avoid obstacles in the yard.
 
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Old 02-08-17, 07:20 AM
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Are you sure the 50 amp breaker is a single pole. A 30 amp,single pole is the largest I have seen. Perhaps this is a single handle double pole like Square D?
 
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Old 02-08-17, 10:50 AM
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I thought the same thing when I read the post but low and behold: Square D QO 50 Amp Single-Pole Circuit Breaker-QO150CP - The Home Depot
 
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Old 02-08-17, 03:22 PM
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I may have an easy solution here....what about a tandem 20 amp single pole. The panel I was looking at is a 70 amp 2 space 4 circuit. I could use one lug with no pigtail or jumper at all. What do you think?
 
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Old 02-08-17, 04:21 PM
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What would that accomplish? You could only use one side of the tandem so you would just have a single 20a 120 volt circuit. (Tandems can't be used for a multiwire circuit and you don't have enough wires for a multiwire circuit.) A breaker box would serve no purpose except as a disconnect and there are cheaper way to provide a disconnect.
 
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Old 02-08-17, 04:27 PM
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Can you please post a picture of the breaker feeding the panel?
 
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Old 02-08-17, 04:50 PM
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I'll post a pic when I get home, it is a square d qo 50 amp single pole for sure that will be in the main panel AR the house to supply the 2 space panel box on the dock.

As far as the 70 amp panel box on the dock goes, it's a 120/240 2 space 4 circuit. The way I understand it, one lug (120v) powers one space for one breaker. The second lug powers the other space for one breaker. I thought a SINGLE POLE tandem 20 amp breaker was for two 20 amp circuits that fits in ONE space therefore requiring only one lug hot. Basically my understanding is that it's 2 skinny 20 amp breakers that take the space of one. If that's true 120v hot to one lug allows two 20 amp circuits, one for the lift and one for the lights and receptacles. The second lug and space wouldn't be used. Am I understanding this correctly?
 
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Old 02-08-17, 05:19 PM
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Here is the tandem breaker I was thinking of for the panel on the dock

Eaton BR Type 20/20 Amp Single-Pole BD Tandem Circuit Breaker BD2020 at The Home Depot - Mobile
 
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Old 02-08-17, 05:24 PM
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I don't know how to loaf a picture but here is a link to the breaker I have for the main panel at the house that will feed the panel on the dock

Square D QO 50 Amp Single-Pole Circuit Breaker QO150CP at The Home Depot - Mobile
 
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Old 02-09-17, 06:12 AM
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The tandem breaker would work in the dock panel to give you two 120V circuits without having to jumper across the panel infeed lugs.
 
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Old 02-09-17, 01:50 PM
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I thought it would work thanks for clarifying that I also made sure the box is rated for Tandem Breakers and it is
 
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Old 02-10-17, 05:44 PM
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I thought the same thing when I read the post but low and behold: Square D QO 50 Amp Single-Pole Circuit Breaker-QO150CP - The Home Depot
I've seen a few, but they are rare.
 
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