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Solar PV Installation Checklist

This section contains a system installation checklist that can be used as a final check for a newly installed system or as a maintenance assessment for an existing system. The checklist covers a variety of topics including the PV array, wiring, charge controllers, disconnects, inverters, batteries, grounding and safety labeling. A licensed electrician is recommended and often required for final utility interconnection, system design, permits and installation.

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PV Solar Installers Checklist

Before Testing the System
Use proper safety procedures and equipment when working with electricity.
Verify that all disconnects are locked in the open position with a warning label. This insures that power can not travel further down the line until properly tested, and warns others that there may be live conductors in the box.
PV Array
Make sure all modules are attached securely to their mounting brackets.
Visually inspect the array for cracked modules, damaged junction boxes, and loose wires.
Visually inspect that all module ‘quickconnects’ are tight.
Open each combiner box and test open circuit voltage on each series string to verify correct voltage and polarity. Recheck torque on all DC terminals.
Before powering up the system, at final array breakers, repeat open circuit voltage tests to verify correct voltage and polarity.
Verify modules are wired so that they can be removed without interrupting the grounded conductor.
Check for labels on the modules. NEC® 2005, Article 690.51: "Modules shall be marked with identification of terminals or leads as to polarity, maximum over-current device rating for protection, and with rated 1) open-circuit voltage, 2) operating voltage, 3) maximum permissible system voltage, 4) operating current, 5) short-circuit current, and 6) maximum power." See NEC® 2005, Article 690.52 for AC module requirements.
Check exposed array wiring for correct rating and sunlight resistant insulation.
Check that all wiring and conduit is appropriately rated, neat, and well supported.
Check that strain reliefs/cable clamps are properly installed on all cables and cords by pulling on cables to verify (NEC® 2005, Article 300.4, and Article 400.10).
Make sure that all grounded conductors are white and equipment grounding conductors are green or bare (NEC® 2005, Article 200.6(A)).
Verify that the conductor rating of the PV circuit is at least 156% of the rated short circuit current (1250/0 X 1250/0 = 1560/0).
Verify that all junction boxes are accessible.
Over-current Protection
Verify that the over-current device rating of the PV circuit is at least 156% of the rated short circuit current (125% X 1250/0 = 156%).
Make sure DC voltage and current ratings are clearly marked on over-current protection.
Charge Controllers
Torque all terminations again.
Check that all voltage settings are properly set for the appropriate battery type and proper voltage.
If the system is connected to a utility interactive inverter, make sure that the settings of the charge controller(s) do not interfere with the proper operation and dispatch of the inverter system.
Verify that charge controller operation matches the programmed settings by forcing the system to the set points and making sure that the unit performs the proper control function. You should test the following points:
  • Low voltage disconnect (LVD)
  • Low voltage reconnect (LVR)
  • High voltage disconnect (HVD)
  • High voltage reconnect (HVR)
Verify that the disconnects are still locked open and the warning label is still intact.
Verify that there are means to disconnect and isolate all pieces of equipment in the system.
If fuses are used, verify means to disconnect the power from both ends.
Ensure switches are accessible and clearly labeled.
Check the continuity of fuses and circuit breakers with power off.
Check voltage drop across switches while operating.
Check individual cell or battery voltages after equalization.
Check the specific gravity of all questionable cells with a hydrometer.
Store safety gear nearby (eye protection, rubber gloves, baking soda and distilled water).
Retorque all battery connections.
Coat each terminal with anticorrosive gel.
Make sure that access to terminals is limited (NEC® 2005, Article 690.71(B)).
Make sure that location provides adequate natural ventilation. Well-vented areas include garages, basements, and outbuildings, but not living areas.
If battery contains flooded cells, top off cells with distilled water according to the manufacturers instructions.
If battery contains flooded cells, be sure an eyewash station is accessible.
Once inverter is operational, “equalize charge” the battery to ensure that the battery is properly connected and functioning correctly.
Ideally, run the battery through a few heavy charge-discharge cycles to exercise the battery.
Inverters in Grid-tied Systems
While disconnects are open, retorque all electrical terminal connections on the inverter to tighten any connections that may have loosened since the initial installation.
Verify in the inverter manual that the array open circuit voltage, under the record lowest temperature, is acceptable to the inverter.
Check utility line voltage to verify that it is within the proper tolerances for inverter. If line voltage is above 124 volts AC before starting inverter, verify that the maximum voltage drop for the inverter output circuit is less than two volts.
If the inverter measures and reports utility or inverter AC voltage on a display, verify that this voltage agrees with a measurement from a high quality, true-RMS AC volt meter.
For non-battery-based inverters, once the inverter has started and is operational, check that the maximum power point tracking (MPPT) circuit is operating. This should be done during clear sky conditions if possible by monitoring array voltage from the open circuit condition until it reaches a point where system power peaks and then starts to drop again. Keep monitoring voltage until you note that the system voltage has been adjusted up and down several times.
Verify that the operating voltage is near the expected peak power voltage for the conditions of the test, this can be found in most manufacturers literature.
Properly connect the temperature compensation probe to control battery voltage.
Follow inverter-starting procedure from the manufacturer’s manual.
Instruct the homeowner on what to do in the event of an inverter-failure and provide them with an initial start-up test report.
Inverters in Battery-based Systems
While disconnects are open, retorque all electrical terminal connections on the inverter to tighten any connections that may have loosened since the initial installation.
For battery-based inverters, use the programming features of the inverter to charge the battery, and then connect the battery to the DC source to ensure that these functions are operating properly.
Follow inverter-starting procedure from the invert installation or operation manual.
Instruct the homeowner on what to do in the event of an inverter failure and provide them with an initial start-up test report.
Verify that only one connection in the DC circuits and one connection in the AC circuits (grounded conductor to grounding conductor) is being used for system grounding referenced to the same point (NEC® 2005, Article 250.21).
Check to see that equipment grounding conductors and system grounding conductors have as short a distance as possible to ground.
Check that non-current carrying metal parts are grounded properly (array frames, racks, metal boxes, etc).
Incorporate ground fault protection on systems required by the NEC®.
Note: Terminal lugs bolted on an enclosure’s finished surface may be insulated because paint finish at point of contact has not been properly removed.
Check resistance of grounding system to earth ground. NEC® allows 25 ohms or less.
Verify that the equipment grounding conductor is a green or bare wire and is properly sized.
Safety Signs
Label any fuse or circuit breaker that can be energized in either direction (NEC® 2005, Article 690.17).
Post an “Interactive Point of Connection” sign for interactive PV systems (NEC® 2005, Article 690.54).
Place a sign at the equipment service entrance that states the type and location of in-site optional standby power sources (NEC® 2005, Article 702.8).
Post a “No Smoking” sign near the batteries.
Place a sign at the point of PV system disconnect listing: operating current, operating voltage, maximum system voltage and short-circuit current (NEC® 2005, Article 690.53).
Provide any additional documentation that would be helpful to the homeowner, inspector, or fire officials.

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