Wiring a Pier for Boat lift

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Old 12-09-09, 07:13 AM
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Wiring a Pier for Boat lift

I just put in a boat lift with two motors (switched) that can take either 1x [email protected] or 2x [email protected] or total 30A (current config). Oviously everyone suggests use the 220 option but I also have other 110 stuff like lights etc out there and only have one circuit from subpanel run to pier now which is 10/2 w/ground (at base of pier). I need GFI, as it is in a boathouse. Issue is if I run a new leg using conduit from box to the end of pier to lift and I then have a single receptipical outlet w/ gfi pulling 2 x 15A or 30A....it will blow the 15A or 20A GFI recepticale. Do I need to wire 2 seperate 15A gfi recepticals in parallell off the 12guage leg I ran? Any other ideas short of pulling a new wire from subpanel?

Great forum BTW, thanks for everyone's input.
 
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Old 12-09-09, 07:34 AM
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Your #12 will only support a 20 amp circuit. Two 15 amp motors will draw too much current on the 20 amp circuit.

You really need to upgrade to a multiwire feed to a small subpanel. This will allow you to change the motors over to 240 volts and still allow for the 120 volt circuits also.
 
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Old 12-09-09, 08:08 AM
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a small subpanel would be tough...

Due to lack of any real location to put it on or near the pier. I guess I could rig something up but it would require almost as much work as just runing another leg.

The junction box I have now is on the 2x10 pier joist and near the water (never goes underwater). BE tought to replace with a subpanel. What if I ran #10 wire instead of #12?
 
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Old 12-09-09, 08:41 AM
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All the conductors must be run together. You just could not add another conductor to the cable that is there.

General purpose circuits are limited to a 20 amp maximum so increasing the wire to #10 won't help for your lighting in addition to the lift motors.
 
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Old 12-09-09, 08:49 AM
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What is the distance from the panel to the pier?
 
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Old 12-09-09, 09:38 AM
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distances (good question):

Sub-panel in garage to junction box at begining of pier is 40 feet. Run with 10/2 w/ ground UF-B. Junction box to lift motors cords about 50 feet. I was going to run conduit with #10 out to there.
 
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Old 12-09-09, 02:12 PM
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I agree with pcboss that you've outgrown your single #10/2 cable. I don't see any way of doing this right without installing a proper subpanel feeder out to the pier -- probably a #8/3g 40A. You will need a double-pole 20A GFCI breaker for the lift plus at least one 20A circuit for general-purpose use and a 15A for lighting.

The panel can be mounted on a wooden or metal post, or even on a frame made of steel strut. I'm not an expert in installs near water, but I do not think that the side of a pier would be a is a legal location for any type of panel or disconnect. Maybe someone else who knows this type of install can give a better idea of how/where to mount the panel.
 
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Old 12-10-09, 07:18 AM
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adding anything near the water is painfull....

It sounds like maybe I just upgrade the subpanel in the garage and use that as my pier subpanel (which is basically all it is servicing anyway rigth now) and add dual pole gfi breaker and use existing #10/3 w/g and as my 220-20a leg out to the lift and just pull and bury another conduit leg out there seperately for lights. Might be easiest. Can I run the #10/3 @220 for 125 feet and still get the 20A I need for lift? I doubt I could at do this 110/15A and pull it off.
 
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Old 12-10-09, 08:16 AM
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Earlier you said you have #10/2 (black,white,bare), but now you say you have #10/3 (black,red,white,bare). This makes a big difference. So which one is it for sure?
 
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Old 12-10-09, 10:10 AM
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"220-221, whichever works"....

I assume you are asking as I would need the 10/3 to do the 220.

I looked last night at the subpanel and I thought it said 10/3 with ground but I also looked down at pier last week and thought it was 10/2 with ground.... another way of saying not sure, need to check today.

Lets assume I have 10/3...
 
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Old 12-10-09, 11:20 AM
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If you have 10/3g (black,red,white,bare) then you can install either a 30A subpanel or a 20A MWBC to the pier, either of which could power the boat lift and a few other incidental lights or general-purpose receptacles. If you have that extra wire, you can get double the power available than you have now.
 
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Old 12-10-09, 02:17 PM
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MWBC sounds like a plan...

Another Shed Wiring Question - DIY Chatroom - DIY Home Improvement Forum

Saw this post on another site (Scroll down to diagram). So if I apply to my pier and what you are suggesting...
I would run my 10/3 w/grd with a dual pole GFI 20A breaker from subpanel in garage to end of pier where lift is. I would use a 220 20A conector for lift plug and then do a MWBC off a leg from 220 (black) and pigtail common neutral for my 110 20a leg (for lights)? Chance is worse case I might have 2 or 3 lights on (60w bulbs) when I use the lift if it where at night.
So I have 1) GFI covered, 2) 220 20a for lift and 3) 110 20a gfi for lights. What am I missing?
 
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Old 12-10-09, 04:43 PM
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I don't quiet understand what you wrote.
can take either 1x [email protected] or 2x [email protected] or total 30A.
Do you mean you can either use one 240v motor or two 120v motors? The reason I ask is a 15a 120v motor changed to 240v would draw approximately 7.5 amps. If you could convert both 120v motors to 240v you would only need 15a. I also don't see exactly how you swap two motors for one motor. Maybe with 120v motors one on each end and with the 240 one motor lifting both ends?
 
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Old 12-11-09, 07:20 AM
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sorry, lost in translation

Ray, thanks for your reply, what I meant was relating to trying to run MWBC out there on the pier. If I ran a MWBC using a conduit of 10/3 w grd I could do a couple of things once at the end of the pier, using the MWBC 1) like have 2x 15A 110 sockets to run lift and 1x 20A 110 for lights (3 total) . 2) Or I could do 1x 20A 220 to run the lift (yes the motors are easily convertable) and then another branch circ of 20A 110 for lights. Is it as easy as pulling a leg from one of the 220 and using same nutral for the 110 branch? the dual pole 20a gfi breaker should keep me in check?

Thanks for eveyones imput, while I could pay someone to do this I like learning a new trade
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"Give a man a fish he eats for a day, teach a man to fish and he will eat for a lifetime"
 
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Old 12-14-09, 08:12 AM
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so i think i have it figured out

I went back and confirmed it is 10/3 w ground UF-B. In fact went in waterpoof jbox and the black wire is pigtailed off with no other conection, the red is what is conected to existing lights (along with white as nuetral and unsheilded ground). Beer 4U2

So my plan is to put in dual pole 20A, (I assume this means that each pole is rated 20A) GFI breaker in the box. Run 10/3 conduit out to the lift and put a twin 20A 110 recepticle that has red hot wire (and 20A)on top recepticle and black wire on bottom recepticle and both wired to common nuetral which should make this an offical MWBC? I can plug in my 2 110 15A lift plugs and be fine.

My other option would be do all of the above except instead of the dual receptical I would use a single 125/250 recepticel and either buy a spliter (125/250 that splits into 2 115s) or rewire the two 110 plugs on the lift motors. MY question is if I use the 125/250 isnt that a 30A receptical and is my double pole 20A underrated and It needs to be double pole 30A?
 
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Old 12-14-09, 08:21 AM
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If you install a small subpanel using the existing feed to the pier you can then run a new circuit for each lift motor and a circuit for the lights. since you have #10 you could feed the sub with a 2 pole 30.
 
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Old 12-14-09, 08:49 AM
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Thx PC, already have subpanel is in garage 20 feet away.

It is a 40 amp dual pole circuit from main panel. It has 1 20A and 1 15A circuit coming out of it. 15A is lights. The jbox i mentioned is at base of pier with waterproof connecters in for some other lights at base of pier. I would bring my lift MWBC circuit out of this (with waterproof fitting).
If I did another subpanel it would be a sub off a sub...plus there is not really a place to put the subpanel and I would have to dig up the original wire to move it to reach the subpanel.
 
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Old 12-14-09, 08:55 AM
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or....how about just hardwireing the lift motors at 220?

take all the worry about the connector crap out, just hardwire in junction box with sealtite
 
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Old 12-14-09, 09:18 AM
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You should not have a 40 amp breaker feeding a #10 cable. The proper breaker would be a 30 amp. I may be misunderstanding tho.

There would be no problem with having a sub feed a sub.
 
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Old 12-14-09, 09:24 AM
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40 A breaker is circuit feeding garage subpanel

That has #6 from main panel to sub, I think. The 10/3 is from sub panel in garage down to waterproof jbox at pier
 
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Old 12-14-09, 09:40 AM
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Originally Posted by sandyharry View Post
take all the worry about the connector crap out, just hardwire in junction box with sealtite
If you do this code requires a disconnect switch, pullout or breaker within line-of-sight of the motors for servicing. A cord-and-plug is considered a legal disconnect. A worker servicing the motors must be able to visually see the power remains disconnected.

That has #6 from main panel to sub, I think. The 10/3 is from sub panel in garage down to waterproof jbox at pier
That sounds okay for a 40A breaker. Possible upsize to 50A would be allowed if the distance is not too great, but no need unless the 40A is tripping with the new boat lift load.
 
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Old 12-14-09, 01:32 PM
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GEEZZZ....Its always something....never easy

Originally Posted by ibpooks View Post
If you do this code requires a disconnect switch, pullout or breaker within line-of-sight of the motors for servicing. A cord-and-plug is considered a legal disconnect. A worker servicing the motors must be able to visually see the power remains disconnected.
----------------

So I am back to thinking I run the 125/250 single recepticle and buy the cord that splits the single recepticle into 2-110 15A for each motor. So the 125/250 recps are usually rated for 30A, right? Does that mean that I have dual pole 30A breaker (30A a pole) or is it dual pole 15A breaker (15A a pole) since it is each leg??? And this needs to be GFI or does the gfi on the lift motors cover my code spec??
 

Last edited by pcboss; 12-14-09 at 02:46 PM.
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Old 12-14-09, 02:01 PM
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There's no problem with wiring the lift as 220V/20A to a receptacle on the 20A MWBC as was the original plan. Use a NEMA 6-20R plug and receptacle or the twist-lock equivalent the cord should be 12/3 type SJOW or something similar with marine exposure rating. The double-pole GFCI breaker covers protection for everything on the entire circuit.
 
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Old 12-14-09, 03:50 PM
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so I need dual pole 20A breakers to provide both 20A...

hots (legs) in the 220 20A recepticle? Damm those GFI breakers are expensive!!!!!
 
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Old 12-14-09, 03:59 PM
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like this?

Use a NEMA 6-20R plug and receptacle or the twist-lock equivalent the cord should be 12/3 type SJOW or something similar with marine exposure rating.

like this?
Leviton CORROSION RESISTANT L6-20 Twist Locking Receptacle Turn Lock Outlet NEMA L6-20R 20A 250V 23CM-20
 
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Old 12-14-09, 04:26 PM
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Originally Posted by sandyharry View Post
like this?
Yes that's correct. The cord should be rated for wet applications too with a "W" in the code such as SJOW. (O = oil/gas resistant, W = wet resistant)

Regarding the GFCI breaker go to an electric supply house. The price will be much less than MSRP posted online. Some of the big box stores also carry or can order a 20A GFCI breaker. The price for Siemens is about $70, SquareD Q0 about $150 -- the other brands fall somewhere in between.
 
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Old 12-15-09, 06:02 AM
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GFI on MWBC...

Spoke to a neighbor that did a MWBC 30A GFI to his pier and the dual pole GFI breaker kept tripping so he pulled it and replaced with no GFI. I have read other places that with MWBC you cant do do GFI because of different carry on the 2 circuits will trip the breaker. Others have disputed this. Whats the view here?
 
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Old 12-15-09, 09:07 AM
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Originally Posted by sandyharry View Post
Spoke to a neighbor that did a MWBC 30A GFI to his pier and the dual pole GFI breaker kept tripping so he pulled it and replaced with no GFI.
There is no legal way to do a general-purpose 30A MWBC in the first place so that leaves me suspicious about the circuit. It is also dangerous to have outdoor wiring, especially near water, without GFCI. This is a serious life safety issue.

If the GFCI was tripping, there was probably wet wiring somewhere in the circuit or a faulty appliance/motor/light and it was doing its job. Occasionally a GFCI breaker does go bad so a replacement will fix the tripping problem, but most of the time a tripping GFCI is a sign of a bigger problem.

I have read other places that with MWBC you cant do do GFI because of different carry on the 2 circuits will trip the breaker.
You can't use a single-pole GFCI breaker or GFCI receptacle on a MWBC. The double-pole GFCI breaker can handle the MWBC just fine.

This thread made me have a flashback of this show from years ago -- amazing it's on YouTube: http://www.youtube.com/watch?v=RR1EMUnRR4w
 
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Old 12-15-09, 09:39 AM
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sold...

ok...so the gfi breaker is done deal...
 
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Old 12-30-09, 08:41 PM
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Cut/Ham dual pole 20 A GFCI CH (tan) breaker for my box is $300!!!! I can upgrade the whole box and add breaker with square d for that much!!

just noticed that the motors for my lift have a gfi swith built into the power cord....does that get me off the hook for the doing the gfci circuit breaker? A regular dual pole CB 20a is $20!!!

I think I know the answer....
 
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Old 12-31-09, 10:35 AM
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Originally Posted by sandyharry View Post
just noticed that the motors for my lift have a gfi swith built into the power cord....does that get me off the hook for the doing the gfci circuit breaker?
Yep. GFCI can be provided by a factory installed device. You do however need to use a twist-lock plug instead of a straight blade so that only the boat lift can use the non-GFCI receptacle. You will also need to use individual GFCI receptacles with no LOAD protection wired if you proceed with the multiwire circuit. GFCI receptacles cannot provide downstream protection on a shared neutral circuit.
 
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Old 01-04-10, 03:17 PM
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So started to run my leg with 3 #10 and grd (bl, wh, red and grn) in 1/2 inch pvc cond using those watertight hoses and connectors on ends. The hole for these couplers is really small. Do I have any derating issues where the rn in the 1/2 is fine but it gets tight at the connectors?
 
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Old 01-04-10, 03:50 PM
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BTW thanks to everyone's help, for those following from the begining the final install is planned to be the following:

1) Box work- Change out current single pole breaker in garage subpanel and add dual pole 20 A (or can I use 15?) and attach red and black wires to the hot on the breaker. This wire is #10/3 w grd in UB that is buried and goes to waterproof j box (~ 40 feet) at end of the pier in a protected spot. I need to add a seperate ground bar to garage sub panel to update and will move the grounds from the bonded nuetral to the new ground buss, and unbond the nuetral buss from the box (it is an attached garage)

2) From the j box at end of pier I will run 1/2 pvc cond using the waterproof cnnectors at j boxes. I will run 4 #10 (blk/red/white/grn) wires through this to a recepticle box just next to my boat lift. (~75Ft) so total distance from panel to lift recpeticle is ~110 feet. I have two lift motors that are 15A rated. I will use two 15A twist loc recepticles (6 15r??) since this is not a gfci protected circuit and run the red wire to one hot and black to the hot on second receptical. I will pigtail 2 white wires to main white wire and use those as my nuetral and run to each recpeticle and of coarse ground to each the same way. I know have MWBC.

I will get 2 regular 3 prong-to-15 A twist loc converters to plug my two motors into to the twist loc receptical. Just up from the plugs on the motor cord are inline gfci breakers. so these circuits are now complete and protected and I will only use this circuit for the lift and the twist loc keeps from being used by other "regular" plugs. I have another circuit that powers lights on pier already.

So what are the snags here?
-Yes I could use dual pole a gfci breaker and regular recepticles but that breaker alone is $275!!!!! whereas the twist loc recps are $10 each and the converters another $5 each.....

-A dual gfci recepticle (marine grade) is $45 and I could use that and then the circuit would be usable for other things then just the lift- one real option-but is redundant given I have gfci in the lift motor cords. I would need to break the tab connecting top and bottom recepticle and wire red to the hot on top recepticle and black to hot on bottom and do the same thing with nuetral to top and bottom (dont break white tabe and just use one wire but I would prefer to just wire them both to be safer.

-I could use 220v circuit but would need to replace the two 110 cords for lift motors which the lift guy quoted me at $120 all in for the service call. And then I dont have a GFCI circuit any longer as the breaker isnt and the gfci on lift motors would be gone when cords were swapped out for one 220.

Thanks again for everyone's help, this site is an awesome tool.Beer 4U2
 
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