Off-grid planning
Off-grid solar: what you can DIY and when to hire a professional
Most off-grid systems are a mix: you do the planning and much of the work, and a professional handles the parts where mistakes are dangerous or code-required.
At a glance
Four ways to get it built
DIY-only
Fits: Portable power stations, RVs and vans, sheds, and small 12V systems with plug-in loads.
You do: Everything: sizing, buying, mounting, wiring, and testing.
Professional does: Nothing, though a forum or experienced friend can sanity-check the design.
DIY with a professional review
Fits: Cabins, workshops, and tiny homes where you're comfortable with DC wiring.
You do: The design and most of the installation.
Professional does: Reviews the design before you buy, and inspects the work before you energize it.
Split the work (partial professional help)
Fits: Cabins and homes with a subpanel, 240V loads, or a generator transfer switch.
You do: Sizing, panel mounting, low-voltage PV wiring, and the battery bank.
Professional does: AC wiring, the subpanel, transfer equipment, grounding, permits, and final inspection.
Full professional install
Fits: Full residences, large 48V systems, roof-mounted building arrays, and anyone who wants a warranty-backed installation.
You do: Your load list and goals, which makes quotes faster and more accurate.
Professional does: Design, permits, installation, inspection, and commissioning.
Task by task: who should do what
| Task | Who | Why |
|---|---|---|
| Listing loads and sizing the system | DIY | Use the planner and wattage chart; this is where DIY saves the most. |
| Choosing equipment | DIY + review | Have someone check that the panels, controller, battery, and inverter are compatible. |
| Mounting panels on an RV or van roof | DIY | Seal every penetration and use mounts rated for highway wind loads. |
| Ground-mount racking | DIY + review | Footings must suit your soil, frost depth, wind, and snow load. |
| Mounting panels on a building roof | Professional | Needs a structural check and proper flashing; falls are a serious risk. |
| PV wiring on low-voltage arrays (under about 50V DC) | DIY | Panels are live whenever light hits them. Open the PV breaker first, never unplug MC4s under load, and use matched connectors and the right crimper. |
| PV wiring on series strings above about 50V DC | DIY + review | Covering panels does not make them safe. Isolate at the PV disconnect, lock it out, verify with a meter, and treat conductors as live, or have a qualified installer do it. |
| Assembling the battery bank and fusing | DIY + review | Follow the manufacturer's series/parallel limits; fuse at the battery, usually Class T for lithium. |
| Battery-to-inverter cables | DIY + review | Cable gauge and fuse rating must match the inverter manual; a loose lug can start a fire. |
| Plug-in loads on the inverter's outlets | DIY | Stay within the inverter's continuous and surge ratings. |
| Connecting the inverter to a building's wiring or subpanel | Professional | Requires a licensed electrician and usually a permit. |
| 240V or split-phase systems | Professional | Wiring errors here can damage equipment or electrocute someone. |
| Generator or utility transfer switch / interlock | Professional | Prevents back-feeding, which can kill line workers and damage equipment. |
| System grounding and bonding | Professional | Must follow the inverter manual and local code; get at least a review. |
| Permits and inspection | Professional | Most fixed building installations need one; check with your local building department. |
| Commissioning checks | DIY + review | Measure voltages and polarity before closing breakers; have a pro verify larger systems. |
- Panels and rackingDIY on vehicles; review for ground mounts; pro on roofs
- PV wiringDIY only under about 50V DC; higher-voltage strings need isolation and a review
- Battery and fusingDIY with a review
- Inverter to building wiringLicensed electrician
- Panel, 240V, transfer switchLicensed electrician and permit
Amber is DIY with a professional review (some parts of these steps are plain DIY, as the table shows), and red is professional work.
- you need to open a service panel or connect to a building's existing wiring;
- your system uses 240V, split-phase output, or a generator transfer switch;
- a wire, lug, fuse holder, or battery terminal gets warm, discolored, or smells hot;
- a breaker or fuse keeps tripping and you don't know why;
- you're unsure how the system should be grounded;
- batteries are swelling, leaking, or getting hot.
How to get a design review
A review is fastest and cheapest when you bring a complete package:
- Load list: what you'll run, watts, and hours per day. The planner gives you this.
- One-line diagram: a simple sketch from panels to controller to battery to inverter to loads, showing every fuse and disconnect.
- Equipment datasheets: panels, charge controller, battery, and inverter.
- Wire and fuse list: the gauge, length, and fuse or breaker rating for each run.
- Site details: where the batteries and inverter will go, and photos of the mounting area.
Look for a licensed electrician with off-grid or battery experience; a NABCEP certification is a good sign. In the U.S., the National Electrical Code covers PV systems in Article 690, energy storage in Article 706, and stand-alone systems in Article 710. Your local building department decides which edition applies and whether a permit is needed.
Where DIY saves the most
- Planning and sizing: an accurate load list prevents buying the wrong equipment. Start with the appliance wattage chart.
- Equipment research: knowing what you need makes quotes comparable. See inverter sizing and battery sizing.
- Mounting and low-voltage PV wiring: labor-heavy work many owners can do well, as long as they treat panels as live in daylight.
- Seasonal planning: sizing for winter sun and cold avoids an undersized system.
FAQ
Can I install off-grid solar myself?
Many people can safely handle sizing, mounting, low-voltage PV wiring, and plug-in systems. Higher-voltage series strings need proper isolation or a qualified installer. Connecting to a building's wiring, 240V work, transfer switches, and grounding should be done or reviewed by a licensed electrician.
Do I need a permit for an off-grid system?
Most jurisdictions require a permit for a fixed installation on a building, even if it isn't connected to the grid. Vehicles and portable setups usually don't. Check with your local building department before you start.
What does a professional design review cost?
It varies by area and system size. A review is usually a small fraction of the cost of a full installation, and it can catch expensive mistakes before you buy equipment.
Who should I hire for an off-grid system?
A licensed electrician with off-grid or battery experience. A NABCEP certification is a good sign of solar-specific training.
Is DC low voltage safe to work on?
Not automatically. A 12V battery bank can deliver enough current to weld tools and start fires, and solar arrays can produce well over 100V DC. Treat both with care.