Jump to content

Welcome to TheMalibuCrew!

As a guest, you are welcome to poke around and view the majority of the content that we have to offer, but in order to post, search, contact members, and get full use out of the website you will need to Register for an Account. It's free and it's easy, so don't hesitate to join the TheMalibuCrew Family today!

Sign in to follow this  
cbftbl87

Shore Power project

Recommended Posts

cbftbl87

So I've about had it with cranking the boat manually, and I plan to purchase a motor for my lift this year.  Before doing so, I am running power to my sea wall so I don't need to deal with a solar panel and extra battery, etc. 

I am tying into a 15A circuit in the crawl space, and the run length from the house to the sea wall is about 70'.  Since that's a long run for the wire and voltage drop may be a concern, I was going to use 12 gauge wire instead of the standard 14 gauge required for 15A.  Does that sound like it will be sufficient, or should I go a step further and use 10 gauge?  In addition to the 70' from the house, I will need a 50' extension cord to run underneath the dock from the outlet to the boat lift.  So about 120' total wire length from the house.  Am I missing something here, or does this sound reasonable?  I don't want to finish this project and find out the motor barely turns. 

Share this post


Link to post
ctvandy23

What amperage is  the motor for the lift?  That should determine your wire gauge as well as what amp  breaker you should tie it into.  12 gauge wire at that length will have less of a voltage drop then a 14.  You can easily go online and punch in your numbers to see what type of drop you would get using different wire sizes.  

Share this post


Link to post
MalibuNation
Quote

 

I used 12 gauge for a similar situation with a longer run.  I also ran another wire for a 220/240v lake pump ... something to consider.

Share this post


Link to post
h2o_nhk

what HP motor are you using?   12AWG at 120' has a voltage drop of ~4% when pulling 13.5 amps (standard 3/4HP single phase motor).  This would give you about 115V at the motor assuming the extension cord is 12AWG as well.  One thing we did notice the last couple years is when the power grid is under a lot of stress on really hot summer days the voltage can be several volts lower during peak hours preventing a capacitor start motor from turning over.  I have 12AWG to my outlet and an 80' 16AWG extension cord to the lift.  On one particular hot day during peak hours I had to get a 12AWG cord to get the motor to turn over and run the boat up.   You will never regret oversizing the wire.  Just gives you more options later.  Just my 2 cents.  

Share this post


Link to post
cbftbl87
9 hours ago, ctvandy23 said:

What amperage is  the motor for the lift?  That should determine your wire gauge as well as what amp  breaker you should tie it into.  12 gauge wire at that length will have less of a voltage drop then a 14.  You can easily go online and punch in your numbers to see what type of drop you would get using different wire sizes.  

The motor draws 7.8A according to the manufacturer. 

Share this post


Link to post
cbftbl87

So based on what some folks are using now, it sounds as though I would be OK with 12AWG as long as I use a 12AWG extension cord as well. 

But it certainly won't hurt to use the 10AWG wire instead to make sure I don't ever need to re-run wires in the conduit.  Thanks for the info.

Share this post


Link to post
electricjohn

Being that its a motor load, I would upgrade to 10 gauge wire.  It will also help the longevity of the motor.  Also, use a specification grade receptacle at the outlet box. 

If you think that there will ever be any type of expansion or improvement on your waterfront, it is best to pull the extra wires in the conduit now or at least add a strong sting if you will be pulling individual conductors.  If your pulling a multi conductor cable (not really allowed in conduit) use one with an extra conductor or two.

Share this post


Link to post
cbftbl87
6 minutes ago, electricjohn said:

Being that its a motor load, I would upgrade to 10 gauge wire.  It will also help the longevity of the motor.  Also, use a specification grade receptacle at the outlet box. 

10AWG it is.

Share this post


Link to post
Shodan01
On April 15, 2016 at 10:20 PM, cbftbl87 said:

So I've about had it with cranking the boat manually, and I plan to purchase a motor for my lift this year.  Before doing so, I am running power to my sea wall so I don't need to deal with a solar panel and extra battery, etc. 

I am tying into a 15A circuit in the crawl space, and the run length from the house to the sea wall is about 70'.  Since that's a long run for the wire and voltage drop may be a concern, I was going to use 12 gauge wire instead of the standard 14 gauge required for 15A.  Does that sound like it will be sufficient, or should I go a step further and use 10 gauge?  In addition to the 70' from the house, I will need a 50' extension cord to run underneath the dock from the outlet to the boat lift.  So about 120' total wire length from the house.  Am I missing something here, or does this sound reasonable?  I don't want to finish this project and find out the motor barely turns. 

I used the yellow jacket extension chords, (150 foot of it) from my house to the dock.  Two lifts, and lights are all running from it without problems.

 

http://www.amazon.com/Yellow-Jacket-2885-Heavy-Duty-Contractor/dp/B000BQM06U/ref=sr_1_sc_2?ie=UTF8&qid=1460852002&sr=8-2-spell&keywords=yellow+jacket+chord+100

Share this post


Link to post
jtrezon

 Just be sure the outlet is GFCI protected... preferably at the sea wall.  It won't hurt if the GFCI is at the house, but leakage current at that distance can cause nuisance tripping.  

Share this post


Link to post
chris4x4gill2

Like said above, make sure you are using GFCI breakers/outlets. I don't like the idea of extension cords run under the dock. I would run wire in conduit.

Share this post


Link to post
justhavinfun

Make sure you check your local codes.  In MN I believe, our outdoor 110 outdoor outlets need to be gfi protected, weather proof and, on a 20 amp breaker, and so far above OHW if they are by lake.  Another thing to note is that is if you are upgrading the gauge of wire for your run make sure you have the same gauge wire supplying it at your junction box.  Code might require it to have it on a dedicated circuit.  Hopefully a licensed electrician chimes in.

Share this post


Link to post
cbftbl87

Project is complete!  I ended up going with 12 AWG wire from the house to the sea wall since I already had plenty of it, and installed a GFCI outlet in a weather proof enclosure.  I tied into a 20A circuit in the crawl space.  I used PVC conduit and just pulled the three THWN wires through it as I installed it....made it much easier than doing it after the fact. 

For the dock, I used a 50' 12AWG extension cord and decided against the conduit, since the dock comes out each year. 

I'm getting 123V no load at the sea wall outlet, then it drops to 117V with the lift motor raising the boat.  So it's slightly lower than that at the motor since this location doesn't account for the 50' extension cord. 

Does this sound like a reasonable voltage drop?  The motor does not seem to be struggling excessively. 

Share this post


Link to post
minnmarker

That voltage sounds pretty good.  Make sure the prong side and receptacle side of any plugs are clean and tight.  Because they are susceptible to corrosion and mechanical wear they are often the first links in the electrical chain to fail, cause voltage drop or arching and possibly overheat or fry your motor.  Clean up the prongs with some fine sandpaper on occasion and if the plug slips in easily replace the outlet.

Share this post


Link to post

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Sign in to follow this  

×
×
  • Create New...