[RE-wrenches] Ground Mount Screening

[Matt Lafferty]

I agree with Bill. Am I the only one who sees this as a 240 VAC application, not a 29.5 VDC application? The AC will be run in cable, not conduit, under the array. Code and common sense say we don't want unqualified people walking up to it and grabbing cables.

If it's a conventional ground rack, lattice is an affordable, reasonably attractive, and effective physical barrier for people and large animals. 

This method also doesn't create an attractive nesting place around the wires for squirrels and other knawing critters like an expanded metal backscreen would. And it doesn't affect module warranties.

$0.02001

Matt Lafferty

On Oct 21, 2010 2:58 PM, Bill Brooks <billbrooks7 at yahoo.com> wrote: 

Drake,



I recommend using 4'x8' panels of lattice work that is either wood or PVC so

that you don't have worry about grounding the material. It is reasonably

attractive and can hide some of the ugly parts of the array. The panels can

be held on with battens that screw into the structural member and allow for

panels to be removed in case the array wiring needs to be maintained.



Bill.





-----Original Message-----

From: re-wrenches-bounces at lists.re-wrenches.org

[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Drake

Sent: Thursday, October 21, 2010 9:35 AM

To: RE-wrenches

Subject: [RE-wrenches] Ground Mount Screening



Hello Wrenches,



We are installing a ground mount system with Enphase 

inverters.  690.31 requires readily accessible source and output 

conductors OPERATING at over 30 volts to be installed in a 

raceway.  The Vmp of the REC230PE modules is 29.4 volts.  Of course 

it would go higher in cold weather.  Do I have any argument that 

would allow us to not install the DC conductors in a raceway?



The NEC Handbook comments "Most PV modules do not have provisions for 

attaching raceways. These circuits may have to be made "not readily 

accessible" by use of physical barriers such as wire screening".



I have heard of a green screening material that has been used on the 

E, W and N sides of ground mounts to render the area not readily 

accessible.  Does anyone know what this is?  What else would work 

that would be more cost effective than running a chain link fence 

around the array?



Thanks,



Drake

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