View Full Version : Running electricity to my dock, need assistance

Scott Brandstetter
06-01-2016, 2:20 PM
As the pictures show, I have a small dock with Jon Boat that I use to fish occasionally but mainly to take the grandkids for rides around our little lake. I have a deep cycle battery to power the trolling motor and instead of hauling it to the house each time to charge, would like to run electric to the dock to keep the charger there. I have electric run to our septic tank and plan to come from that to the dock.

338448Overall look, septic in front right, dock in back left.

338450close up of current electric at septic system

338451Close up of the dock

My thought is to run underground 14/3 wire from the septic outlet and at the dock add pvc from 12 inches down in the ground to along the edge of the dock. I would use a GFCI outlet and house the outlet in an outdoor waterproof pvc case. Any help would be appreciated. I think the fact that water is involved has made me extra cautious and looking for confirmation.

Keith Outten
06-01-2016, 2:29 PM

I suggest that you purchase a solar panel to charge your battery. A small inexpensive panel will do the job nicely unless you require a quick charge which is possible with a larger panel and a charge controller.

Scott Brandstetter
06-01-2016, 2:46 PM
Thanks Keith and that was my first thought. Spoke with a few companies but because it is a deep cell battery they said the size I would need to charge would be very large. They did say I could get a smaller one to maintain the battery but not recharge. I don't understand it all but they had the chance to sell me something and didnt. Now I am at plan B.

Von Bickley
06-01-2016, 3:00 PM
You will need to know a couple of things.
What size wire is going to the septic tank and how much current does the septic tank equipment draw?

What size breaker is on the septic tank equip.?

Chris Padilla
06-01-2016, 3:49 PM
What is the distance of wire you plan to run?

Scott Brandstetter
06-01-2016, 4:10 PM
Thanks for the responses. The septic tank is on it's own circuit and it is a 15 amp breaker with 14/3 wiring. I was planning to continue with 14/3 underground approved wire and run it approx 100 feet to the dock.

Pat Barry
06-01-2016, 4:15 PM
I run a battery charger using an outdoor 14/3 extension cord over a distance of 100 feet and it seems to work fine so 14/3 solid wire should be fine for a similar distance for a battery charger. I'd have to research proper placement of the GFCI device(s).

Tom M King
06-01-2016, 4:50 PM
Rent a walk behind trencher, and use UF wire.

Wade Lippman
06-01-2016, 5:08 PM
We would need to know how far the box is from the panel and how many amps each device draws.
Why 14/3?

Charlie Velasquez
06-01-2016, 5:37 PM
Check with your local AHJ. If there is none I would suggest:
-Go deeper than 12". I believe you have to if it is not in conduit.
-That is a long run. I would go with 12ga.
-Sooner or later something will go bad in the wiring. I think it is better to have the GFI protection at the service panel. You could have over 100' feet of live wire if something goes wrong near the outlet. If you don't want to splurge for a GFI circuit breaker, consider adding a GFI utility outlet on that circuit right at the service panel. (You may already have GFI protection at the septic tank, but I prefer to add it to the wire BEFORE it goes outside)

Von Bickley
06-01-2016, 5:49 PM
When you say 14/3, I assume that you mean 14/2 with ground. Do you know how much current the existing equipment is pulling?

Tony Zona
06-01-2016, 6:04 PM
Here are two examples of why I would hire a professional. I don't know what went wrong in these examples, but wiring near water gives me the willies.


Keith Outten
06-02-2016, 8:19 AM

Do a search on YouTube and you will find lots of information about battery charging with solar panels. One video I found was about a solar panel that ran a pond pump and an overhead fan from a mid sized solar panel and only one battery.

I started with a 7 watt panel, it was slow but it would fully charge a 80 AH lithium battery. I recently purchased two 45 watt panels to charge the batteries for my network and provide lighting during power outages. I am far from being knowledgeable about anything electrical or solar powered but I have been experimenting and its pretty slick how well they work.

Ole Anderson
06-02-2016, 10:40 AM
There is a strong possibility that your septic tank (pump?) is required to be on a dedicated circuit. Check with your local electrical inspector. He will tell you what options he would approve. Personally I would weigh the cost of a solar panel solution against the cost and hassle of a dedicated 20 amp GCFI circuit using direct burial UF cable.

Bob Grier
06-02-2016, 11:38 AM
Solar doesn't care if battery is deep cycle or not. Deep cycle batteries just have thicker lead plates with less surface area. Starter batteries have more surface area to deliver high instant amp output for cranking but don't last long in deep cycle applications. What matters is the capacity of the battery (amp hours AH) and the amount of energy available for charging between discharging. More energy available, the faster battery will charge.

I had bank of five 125AH AGM deep cycle batteries on my boat and charged them with solar and 3 stage charger. I am sure you can find rather inexpensive solar to charge battery.

Note that lead acid battery life depends on how it is maintained. Discharging below 50% capacity significantly reduces life. Over charging or low water/electrolyte does same. If you don't use battery often, then short life is probably not a dollar issue. If it is, then get a solar powered 3 stage smart charger to connect to the solar panel and don't discharge battery below 50% of amp hour capacity. That means don't use more than 60 AH of a 120 AH battery before charging.

Lead acid batteries come in different types, liquid, AGM, gell. Each type recommends different charging voltage for optimum charging and life cycle. Also, the sealed AGM and gell batteries can only take so many amps during charging. Too many amps and the electrolyte boils which is bad. A decent charger won't let this happen. Lithium is different too. Just something to keep in mind whether using solar or grid for energy source.

Adam Herman
06-02-2016, 12:17 PM
I use solar for my slide in campers and have built 2 systems, also we have a 4200 watt grid tie system on our home. I suggest the renogy kit off of amazon for an easy to set up system that is reliable. how many amphour is your battery and what is the current draw on the trolling motor? How long do you usually use the trolling motor in one day? in my experience a 100 watt panel will run my camper's lights and compressor style refrigerator indefinitely.
i have the components in this kit installed in my current camper, the new renogy kits have a different charge controller and I like the load side to go through the controller.
http://www.amazon.com/gp/product/B01BHD1DPY/ref=s9_simh_hd_bw_b2RMf7L_p86_d0_i5?pf_rd_m=ATVPDK IKX0DER&pf_rd_s=merchandised-search-2&pf_rd_r=18A3RQB4M3VPR2W7J8Q8&pf_rd_t=101&pf_rd_p=cda561f3-60b8-4333-8d8c-095d40efbb7d&pf_rd_i=2236628011

to run the line correctly, you will have to run an entirely new circuit. solar will be cheaper and just as effective. mount the controller in a water proof box on the dock, the panel on a post and have a cable to plug into the boat.

Darrin Johnson
06-02-2016, 11:23 PM
Water and boat dock wiring is a dangerous thing. Recently a young girl lost her life here in Alabama: http://whnt.com/2016/04/16/hartselle-teen-drowns-in-smith-lake-while-swimming-with-family/

I've got a dock (fixed, pile driven) with 220 wiring for 3 boat lifts. Subpanel on the dock. The subpanel is all wired with GFCI's to the various outlets and lifts.

If I had it to do over again, I would have put a outdoor rated subpanel with a large GFCI on the shore, close to the dock and then had a second subpanel on my dock....also with GFCI's. The main panel is 100+ feet uphill from my dock and too far for a large GFCI (probably).

I'm not an electrician....but if I were you I would either hire a knowledgeable electrician or at the very least put a panel onshore, outside, easily accessed with GFCI to kill power to the dock in an emergency. It also allows for easy resting when it trips accidentally. Lake of the Ozarks does this.

Be safe, kids swimming @ a dock with electricity is a potentially tragic situation. AC power and water=paralysis.

I do have a friend who uses 12V solar for docks. If you PM me I will put you in contact. I honestly know nothing about his setup but he uses it at his dock on the lake where the young lady above lost her life.

Lastly: Mike Holt's forum is a good site for research. It's for the pro's...don't expect to post and get answers but you can learn from what is there.

Be safe, best of luck.

Art Mann
06-02-2016, 11:33 PM
Where I live, the local electrical code requires that the wire be buried 18 inches deep everywhere whether it is run in conduit or not. I won't repeat the comments from Keith and Ole but I agree with both of them. I suspect that your current plan is a violation of the electrical code in your area.

Scott Brandstetter
06-03-2016, 10:29 AM
Thanks to everyone for the honest comments. I am going to research solar panels a lot more and figure out the right setup with them. I am going to abandon the idea of electricity 100%. When I started the thread I had concerns which many of you have confirmed with your messages and for that I am grateful.

Everyone have a safe and enjoyable weekend.