Boat Dock & Solar PV System

Status
Not open for further replies.

dereckbc

Moderator
Staff member
Location
Plano, TX
Got a friend who has an odd situation I have never ran across and thought I would run it by you all.

He has a boat dock completely made out of wood with a fiber glass canopy. No metal anywhere other than bolts and nail holding the thing together. It is supported by pile driven wood poles. There is no utility service conductors of any kind ran to the dock.

He has a 400 watt solar panel on the canopy using a charge controller to keep batteries charged up, and the batteries running a 2000 watt inverter.

The inverter only has plug receptacles for the AC output which is both CB and GFCI protection. The inverter supplie one boat lift, one overhead light, and a stereo. The inverter is 12 volt and made for a vehicle. It has a ground terminal.

The question he asked me is how to ground the inverter? I say it does not need a earth ground reference. What say you?
 

SG-1

Senior Member
690.43 indicates that grounding is required.

You did not state the inverter or charge controller is listed for ungrounded operation as required by 690.35(G) or that the system meets all the requirements of 690.35(A) through (G).
 

dereckbc

Moderator
Staff member
Location
Plano, TX
Thank you for the reply. Ok assuming your are correct, I am still not sure; how would one construct a GES on a boat dock?.

My confusion lies with exceptions of 690.35, because the inverter and raceways meets the qualifications. Secondly the inverter itself is not bolted down and part of the structure which is another qualifier for 690.43.
 

dereckbc

Moderator
Staff member
Location
Plano, TX
Are all loads cord & plug out of the inverter ?

Yes they are. The inverter has no terminals for premise wiring methods. All outputs are GFCI receptacles. The inverter is made for a vehicle, not premise wiring. The ground terminal supplied is intended for the vehicle frame or chassis bonding. This is why I am not certain about earth grounding requirement. All loads have an EGC and GFCI, just no bond to dirt.
 
Last edited:

SG-1

Senior Member
I see all are cord and plug in the OP.

I do not know that I am right only my limited interpretation of the code.
I am thinking that all componets would have to be fastened down for a compliant installation and listed for the conditions.

The issue is that the inverter is out of it's normal enviroment & grounding may cause more problems than not grounding. Possibly energizing the water near the dock. It does not need the ground reference to work, but does it need it to be safe ?

Since it is not fastened in place it will be touched every time something is plugged or unplugged.

See if the case is internally connected to the neutral ( large slot of the receptacle ).

Bob (iwire) just finished a solar school.
 

dereckbc

Moderator
Staff member
Location
Plano, TX
Yes I know Bob, and I have designed several solar PV systems in Telecom sites and those are no brainers. Just trying to save a few coins for a friend. I have no problem telling him to install e ground electrode but have never spec one out for a boat doc. I assume run the GEC back to shore to two driven rods on the shore?
 

SG-1

Senior Member
No problem helping a friend, if we don't do it, nobody else will. We both like our friends the same way - alive & rich as possible.

Here are my thoughts on the GES.

Drive the rods 20 or 30 feet from the shore. ( I have a fear if the electrodes become energized due to an uncleared fault the water may become energized also. )

Use an insulated conductor that can be buried between the dock & the rods. ( for the same reason above. The voltage gradient will be the highest near the electrodes should they ever become energized. If the GEC is bare then the voltage gradient will run all the way to the dock & water. )

I would also tell him that if he is ever using an extension cord that could fall into the water to always plug it into the power source last, after the cord is un-rolled and laying on the dock or shore near the water.
 

dereckbc

Moderator
Staff member
Location
Plano, TX
The 2008 NEC defines ground as the earth, but a lake is part of the earth.
I would run a conductor to 2 ground rods.
:grin: Well Tom I kind of figured that part out, but I guess my question is do I run the GEC along the dock ramp back to shore, or is there some way I am missing to drive them in the lake bed below the dock?
 
Status
Not open for further replies.
Top