Reminder for those with PV panels on the roof

[payaso del mar]

Especially if you have them mounted more or less flat, clean em every so often.  Dust & road grime buildup can reduce your output by 10% or more, per the Calif Energy Commn's excellent intro-to-PV guide*.  We had major dust storms all last week and I was wondering why the voltage I was showing while charging was down by .1-.2 volts from normal.  Turns out this is why.

*http://pdf.wholesalesolar.com/guide.pv.installation.pdf?_ga=1.190512427.1013234819.1425591403

[payaso del mar]

another item I learned about last night:  I was reading the electrical code compliance book on solar installations, because we're in process of installing a 2.8KW/day system at our cabin and I wanted to be sure it meets code even if we'll never meet one of the 2 code compliance officers for all of Sandoval County NEw MExico.....

anyway, the NAtl Elec Code requires that the metal frame and similar parts of the panel be grounded.  probably a good idea even in a vehicle application, esp if you have a fiberglass body rather than aluminum

[zero]

You could drive yourself crazy trying to adapt any version of the NEC from 2008 to present to solar installations. Technically - rooftop panels on a residence also require ground-fault protection even if just low voltage DC power.  Oddly solar panels on a residence if on a sidewall instead of the roof do NOT require ground-fault protection. Good luck with that one.  Is an RV a "residence?" I guess not as long as it's not sitting on blocks and hard-wired to shorepower somewhere.   As far as grounding the aluminum frames on the panels- an RV has no earth-ground anyway - unless it is parked AND connected to shore power.  So - it seems moot to me unless a person is going to drive some ground-rods into the ground every time he/she parks to camp. For a family like mine - who never camps in campgrounds with "shore power" - nothing on our RV is ever grounded.

[payaso del mar]

I was being less than accurate with my terminology....I realize that connecting to the vehicle frame is not a "ground" but that's what I was referring to.  and I don't think the county code compliance folks will be knocking on the door of yer toyhomes any time soon, but I also think it's still worth trying to wire to NEC and/or ABYC standards when you can.  unlike AC GFCIs, ground-fault protection on DC circuits is not for personal safety, it's fire prevention.

yes, this probably isn't necessary....but I could visualize the hot wire possibly wearing through the insulation if it touches the panel frame.

[Maineah]

12 hours ago, payaso del mar said:

I was being less than accurate with my terminology....I realize that connecting to the vehicle frame is not a "ground" but that's what I was referring to.  and I don't think the county code compliance folks will be knocking on the door of yer toyhomes any time soon, but I also think it's still worth trying to wire to NEC and/or ABYC standards when you can.  unlike AC GFCIs, ground-fault protection on DC circuits is not for personal safety, it's fire prevention.

yes, this probably isn't necessary....but I could visualize the hot wire possibly wearing through the insulation if it touches the panel frame.

Some states insist that each panel in the array have circuit beakers don't know how that works out with MH's. Pretty much every thing in a MH has a "ground" to the frame work this avoids "ground" loops it won't hurt a thing and may prevent some issues.

 

[payaso del mar]

yeah, that's kind of where I was going.  hard to have anything too well grounded.  I often add a short jumper and a 2d grounding point to any grounds, just for redundancy when things start to corrode and oxidize down the line.....