We recently acquired 100 free 150w solar panels and accompanying inverters/shut-offs for a grid-tie system. We want to ground mount them on our 8 acre property. We don't have the money to hire a contractor at $22k and even quotes for just electrical were $14k.
I would like to do the work myself. I have the time, and am willing to do my homework, but I would be curious what other's experiences have been.
The structural stuff doesn't seem too daunting. I have a spec sheet for California ground-mount requirements for 105mph winds using 1.5" SCHED 40 steel pipe and have already drawn up those plans (who can have more stringent regulations than CA, right?) We need our plans approved by an architect to get a permit from the township, but again, this is doable.
The electrical is where it gets daunting. The panels are rated for 34.5Vmp 43.5Voc 4.35A. I've already planned out the panel arrangements - we plan to use 88 of the panels (two rows of 4x11 panels wired two series of 11 in parallel for 473Voc 9A per 22 panels. These four 473VDC lines would run to a j-box, solar breaker box in the nearby shed, then 100ft to the DC disconnect, inverters (Sunnyboy 550VDC 13A continuous), combiner, AC disconnect, meter and finally the main OCPD (breaker box). I won't get into grounds here. I feel I could figure out all the wiring until the meter, since everything can and will be dead up to that stage. At this point, before powering everything on, I could have an electrician/solar expert inspect my work and do the final hook-up.
This would involve me drawing up my own electrical plans, and even more challenging, finding an electrician willing to just do that final step. They all seem to want bigger contracts or nothing to do with solar.
For those of you who have been through this process, was it manageable? Worth it? Things to consider/avoid/re-consider? Even if you've only worked on DC off-grid systems, your experience is welcomed!
I can't say I've personally worked on a similar project, but I work at an architecture firm in the Bay Area (though I am not currently an architect) so I'm somewhat familiar with the legally required process.
The code relevant to solar panels is only about 15 pages, and is Section 690.
If you don't live in California, your local jurisdiction will tell you the applicable electrical code, generally it's on the county or city building department website.
The process you generally go through to legally get something like this done is get a permit for the work at the local city or county building department, wait for them to review it, and issue you the permit. After which the work can be legally completed, and a final inspection takes place where everything is checked out to make sure it's up to code.
A contractor would generally be the one going through that process, and knowing all the local requirements and codes will make their job much quicker. If you're going to do it, expect it to take 2-4 times as long, assuming you have no previous building department experience.
You've got a fantastic opportunity, but here are a few hurdles you need to be aware of.
First off you need to find out exactly what your permit process will entail. You have enough acreage you're probably far enough out to not need approval through planning, but I don't know. The permit will probably cost you a few hundred dollars, not counting the couple hours you lose dealing with the local government. Inform yourself of everything before going through with it! A phone call can probably get most of your questions answered, but a visit to the local building department will probably serve you better. Most of the people in building departments are fairly nice if you're sociable. Make sure to note if they tell you that you need something signed/stamped. If you need an architect's stamp, getting the documents together will probably be a 1-5k , assuming you don't have building/site plans ready for them to print up and stamp.
Secondly, I'm not an electrician, but my understanding is that for DIY projects, the best, least risky option, would be to talk to the electrician who's going to do the work for you, and run the wiring for him/her. That will save you quite a few billed hours, depending on the scope of the project. But to satisfy legal requirements you want a licensed electrician to actually hook everything up. My understanding is that to connect anything to the electrical grid directly, you need a licensed electrician. Your jurisdiction might let you completely DIY the project under an owner builder type arrangement, but I have no experience with those codes. It is more likely they will allow you to DIY everything but the final hookup to the house and electrical grid. No matter who completes it, it will have to be built up to the California Electrical Code standards, or better depending on local codes, An inspector will come by to check. (Unless you're in one of the few areas of the state where codes aren't followed.)
Hi Zane: Newbie Here, but just wanted to say " 100 FREE SOLAR panels WOW" I just recently Installed 10- 120 watt solar panels on my work shop,, with a 880 amp batterie bank storage. Before I started I knew only the basics of electricity,but through the internet I got a great education. I can now run all my lights and tools ( except the large 220v tools) on the new solar system. And did all the work myself. I would recommend an mppt charge controller, or several in your case, as this would make your life much easier. I f you want to save some money, make your own combiner boxes, and crimp your own ends on the large gauge wires and even make your own lugs.
Its not usually too big a triffle. I would call your permit office and simply ask what is required to get permits and the process to final inspection.
The requirements vary so much that we have to ask on every new install.
For mounting, many mounts have an engineer stamp on a spread of scenarios and it is included on a "cut sheet" or copy of individual product specs.
Sometimes a plan review is not required, sometimes electrical permitting is not even required by the municipality unless you are going to grid tie and the utility has it in the policy on their side.
Next is the utility. Call the rep for renewable interties and download a copy of all pertinent sections of requirements to intertie.
In Michigan, it is generally just a few sheets of paper to review and sign in total. I have never seen a jurisdiction that will not allow a homeowner to do the electrical work. Generally you have this authority and give this authority to a person or company for hire who are recognized by the juris as qualified to do it safely for money and accountable through " licensing". Some places flip it and you are a nobody unless licensed, i think mostly in europe, but am not sure outside of areas we operate.
Electricians will look sideways at you doing most any work that they cannot supervise, and some wont even entertain you doing anything if they pull the permit.. liability. Some may pick up wherever "existing work" leaves off and many will inspect and give helpful advise if you ask or pay for the service.
There is generally nothing in a direct grid tied system that is outside of a competent electricians capability.
NEC states, systems are to be installed only by qualified persons...
It means familliar with all aspects of the installation and materials equipment and techniquies used to accomplish it.
Your voc looks a little high if 550voc is max. Possibly not, as this is affected by coldest recorded temp as a reference and the pv module has a temp co-efficient to use for max voc vs coldest operating temps and i dont know the make and model of inverter.
May not be an issue, but it should be reviewed even if that were the original configuration, and definitely if at a new location with a different climate.
Read all manuals and follow all instructions from manufacturers.
My view is that once you are familliar with the techniques involved with the mechanical and electrical and adhere to manufacturer specs and instructions along with a code review as it applies to your system, most anybody can do it themselves.
If you are not confident, seek professional help.
posted 7 months ago
These tools may help.
Mc4 crimp tool. Rensteig makes fine crimpers, pricey though. I found suitable crimpers as low as $30.
It has been some years since I worked with solar, and I maxed out on a small 2 KW off grid cabin system. But I do know that now there are things called micro-inverters, which is basically a little inverter that sits on the back of each panel, or perhaps a small group of panels. If they are relatively inexpensive it might save a good bit on wiring since you will be moving AC from the panel area to the other stuff, rather than DC which requires fat expensive cables to move it any distance. If you have to run the DC a long way it might even be worth it to sell the inverter you have and get the small ones. I also know that another very important difference between grid-tie and off-grid is that the system must have some kind of automatic shutdown or disconnect in case the grid has an outage. That way power line workers won't get shocked by power coming back into the system from your solar when they think there is no power in the area!
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