Solar mounting.. roof vs pole-top?

[AdironDoc]

Was wondering about the benefits/drawbacks to each. My cabin will end up being situated in a southwesterly direction. I think that the panels would need to be tilted towards the south on a tilting rack? Moreover, the steel roof is not the typical running seam in that the pinch points are not at 90 degree angles to the roof surface. The roof also makes it impossible to use the easy on pinch clamps for the rack. I'd need to drill through to catch the rafters, I suppose.

Considering I plan on running a system on the order of 400W, give or take a hundred, would it be easier to mount them away from the cabin to assist in orientation and avoid drilling through the roofing?

Doc

[glenn kangiser]

Probably a toss up labor wise.  Currently at the cost of panels a tracker is not cost effective so a pole or even a rack on the ground will work provided access to the sun is not obstructed.  Rather than tracking now Dave recommends just adding more panels.  The main reason for a pole is for a tracker.   

[MountainDon]

My own feeling is that roofs are not ideal for mounting modules. They seldom point in the right direction so simple mounts get more complicated. If one wants to make seasonal adjustments to the tilt one must climb to the roof. I'd rather stay off the roof as much as possible. Modules mounted on metal roofs should have a ground fault device installed to prevent accidents id something goes wrong, gets frayed, whatever.

Ground mounts are fine as long as grass is kept trimmed and there is no snow to pile up and cover panels, nobody to drive into them and so on.

Pole mounts are easy to adjust to your best south exposure and easy to build to be adjusted for seasonal tilt changes if desired. And a pole keeps you off the roof.

Roof mounted modules will likely run hotter than if they were mounted on a pole. Roof mounts sometimes restrict air circulation around the modules. Modules mounted on the same plane as the roof are especially susceptible to heating but that is sometimes required by city codes. Then there is the reflected heat from the roofing to be considered. Pole mounted modules have both front and back both of the modules exposed to free movement of air. Higher temperatures reduce PV output.

[glenn kangiser]

Good points, Don. 

[AdironDoc]

Great info Don and Glenn. Thanks! The pole mount sounds like the best plan for me. I'll hoist it high enough to have unobstructed sun and prevent them from ending up in someone else's hands.

[Squirl]

I would do a Pole or Ground Mount. There was a good article in last month's home power.  Don gave some of the better points I will try and add to the points not touched.

Security.  Roof Mounts are much more difficult to steal.  I would install security nuts or bolts when mounting.  If robbers are going to do the trouble of cutting it down, I don't think mounting them on the roof would stop them.

Along the topic of snow.  Cleaning panels year round is a constant maintenance.  It is a lot easier from the ground. 

If you have the cleared land with good sun, I would go for the ground.  Also, I am leery of cutting, mounting, or screwing into the roof over my head.