How to Install a PV Solar Panel System
There are many ways to install solar panels. Here is a step-by-step method for installing grid-connected solar panels on a residential roof. You can also follow these general instructions as a practical guide for most any type of solar installation project.
Like any home improvement, the process starts with good planning. The old adage to
measure twice, cut once certainly applies to PV systems. Knowing the right component parts will also ensure proper installation that is covered by the manufacturers warranty.
The tools required for solar installation are quite common; a measuring tape, a level, a chalk line marker, a good cordless drill, a socket wrench set, screwdrivers (flat and phillips), a hacksaw and possibly a razor knife. A tool belt or vest will especially come in handy. Be sure to follow proper safety precautions when working on a roof and be prepared with a sturdy ladder, hard hat, rope line, and good footing. Given the size and weight of solar panels, this is a two person job.
Follow These 10 Steps to Install Solar Panels
Like any household project, a good plan is important to success. Take accurate roof measurements, allowing space for vents, stacks or other gaps in the array. Be sure to allow adequate space, generally 36", around all four edges of the array. Know the direction and distance between roof joists or support beams to ensure correct attachment and weight distribution. Solar panels operate best when elevated 4" to 6" off the roof surface to allow for airflow and venting. Think ahead about where your household electrical service box is located, and determine the best path to connect to it.
Always read the installation instructions provided by the manufacturers. These manuals will often often include the specifications and physicals dimensions for every component to be used. Once all your information is assembled, create a sketch of exactly how the solar array will fit on your roof. You should know in advance the precise location and number of roof attachments, the location and direction of mounting rails, the placement of each solar panel, the type and location of all wiring and how to make the electrical connections.
For more information about getting started, follow this link to learn
HOW TO MEASURE A ROOF FOR SOLAR PANELS.
If you want professional help, we offer a
FREE Solar Design Service with most systems.
The basis of a good installation is the attachment used to secure the array to the roof. The attachment is usually a bolt (also known as a lag bolt or lag screw) anchored directly into the roof support beams (joists) with some form of L-foot or other device that will connect the bolt to the support rails. These bolts need to be a specific length and diameter to ensure proper strength. Use a chalk line to mark the location of roof joists or beams. Then refer to the design sketch from Step 1 to identify the location for each attachment. Lift or remove a shingle, drill a pilot hole, then secure the lag bolt and L-foot to create an attachment. Use special roof flashing or long-life caulking designed for solar installation to prevent any leaks. Repeat this process for each attachment.
There are many kinds of roof attachments. We can supply the parts that work especially for your roof. Follow this link to learn more about different
SOLAR PANEL MOUNTS.
Mounting rails are connected to the roof attachments using supplied hardware bolts or clamps. There will be two rails for each row or column of solar panels based on the design layout. They are available in standard lengths. These lengths can be cut to size or spliced together to achieve the overall dimensions of the solar array.
The rails are made of anodized aluminum alloy for light weight, strength, corrosion resistance and long life. Solar rails are engineered for standard or heavy duty strength to withstand wind speeds from 90 mph to 150 mph. Depending on your design layout, PV mounting rails can be placed parallel or perpendicular to the roof joists.
Following good engineering design practices, it is important that the roof attachments and rails adhere to proper distance spans for adequate support of the solar array. Generally, you can allow 48" to 72" between attachments along a rail run. A shorter distance between attachments will results in a stronger array. Be sure to level the rails using the adjustable attachments for a uniform and solid fit.
Follow this link to discover the different types and brands of
SOLAR PANEL MOUNTING RAILS.
Now that the mounting rails are securely in place, the racking should be properly grounded according to NEC and local building standards. This is commonly achieved with copper wire run along the top rail and attached using WEEB or other grounding lugs.
With the rails and attachments exposed, this is also a good time to attach any junction or combiner boxes to the rails for later use. The use of wiring boxes will vary based on the system design.
When the installation calls for micro-inverters, this is when you attach them to the rails using the grounding lugs or other hardware. Connect the inverter cables using trunk or other AC cables in a string along the rails. Use cable clips to secure the inverter cable to the rail. Be sure to refer to the system design for proper string sizing, and use branch termination caps as required.
Follow this link for detailed information to
LEARN ABOUT MICRO-INVERTERS
If the installation uses a central, string inverter, it can now be mounted and wired according to the system design plan and manufacturer instructions. The inverter can be mounted indoors or outside. Be sure to mount the inverter in an accessible location, allow proper ventilation and spacing to avoid over-heating. Do not mount inverters in direct sun.
Once properly mounted and wired to the solar array, the inverter can be configured and commissioned for use by following the steps in the instruction manual.
Follow this link for detailed information to
LEARN ABOUT INVERTERS
Now that the inverter(s), wiring cables and junction boxes are secure in place, you are ready to wire the home run cable. The home run will extend from the solar array to the household electrical box. The home run cable can be multiple AC or DC cables, and proper grounding, using common PV electrical wire as specified in the system design. Be sure to use conduit to house the wires.
Before connecting the home run cable into the household electrical service, a safety switch disconnect box is required by NEC code and many local building departments. Essentially a circuit breaker box with a manual switch, the disconnect can be mounted near the solar array or near the main electrical box. Many string inverters have an integrated DC disconnect box, while AC micro-inverter systems will call for a separate box. For convenience, it sometimes makes sense to have two disconnect boxes, with one at the solar array and another at the main electrical service box.
This is also a good time to apply the various safety labels. These NEC code required labels should be included with your system for the disconnect, circuit breakers, and any conduit with a solar circuit. Some jurisdictions may require an engraved placard with a map of all major components.
With the roof attachments, rails and grounding in place, you are now ready to mount the solar panels. Lay one solar panel at a time onto the rails. Use the M/F output cables on the back of each panel to create a string, connecting the cables of one panel to another as each module is added. If using micro-inverters, then connect the solar panel output cable to the micro-inverter input. Secure each module using the end clamps or mid-clamps specified for your solar panel and mounting rails.
Follow this link to shop for
Solar Panel Clamps
It is important to test the electrical connections and output of the solar array prior to connecting the system. Use and amp or volt meter at various locations of the array and wiring to determine output. Once tested, the inverter(s) will require commissioning and optional monitoring installation to start-up. Follow the steps in the instruction manuals for proper setup of inverters or micro-inverters.
Be sure to complete any building or utility inspections before connecting the system to the main electrical panel. Always follow safety precautions to avoid damage or shock hazard.
A handy guide to remember many of the steps involved in safely building a solar panel system can be found at the
solar installation checklist