Solar Array Safety Measures For Homeowners

 

Introduction

When installing a Photovoltaic (PV) system in a residential area, professionals use prior training from OSHA for hazardous conditions in order to better prepare themselves for any possible situation that may occur while on the job. All employees of and company that connect to the grid are required to pass the Electric Power Generation, Transmission, and Distribution Standard in order to see the field [1]. Before they install any system workers also cover job site safety practices including slips and falls, planning for emergency-response events, and identifying any potential safety hazards that could limit the project completion [2]. It is important to keep in mind that once a PV system finds a source of light, that it is already creating energy and is a live circuit that can shock someone who may come into contact with it [3].

 

Standard Inverters consist of 20 strings connected to the modules and 8 strings combined together make a table. All together there are 320 connections made that go into 2 tables that will eventually connect to form a combiner, 2 of these combiners are connected to create 1 tie box. The inverter itself is made up of 7 tie boxes. [3]. With all these connections it is easy to see that there is a chance for error to occur within the system. Error generally come in the form of a fault. Photovoltaic (PV) modules that are a source of DC power are liable to malfunction at faults in the circuit. When energy reaches the fault, prior installed protection devices are unable to resolve the problem and energy build up located at the fault is greater than what the circuit was designed to handle and creates an Arc Flash. The reason that the installed protection would fail is because the PV module wasn’t designed for a nonlinear system that would account for the potential incident energy (the point of an Arc Flash). Instead, the module would be constructed to use a linear circuit which is a stable for those used in batteries [4].

 

When these Arc Flashes occur they spark and ignite the solar panel. The first priority of the first responders is to handle such an incident is to shut off the power to the system, this is can be a complicated problem with a PV system though as it is still generating power. One of the most serious problems for firefighters can be coming into contact with the source current which could be fatal. [5]. To combat flames coming from solar panels Firefighters are trained to mist them with a 20 foot spray making it nearly impossible for them to be electrocuted. It is also a priority to stop the flow of light to the existing panels in the rest of the system so they use a tarp to cover the panels, however, in some cases the tarp used may let light still seep through and powers the PV cells. It is important that they are always cautious [3].

 

The problems of the faults causing Arc Flashes, as explained before, may stem from the guidelines for the production of the modules are not being followed to the exact specifications of NFPA 70E and CSA Z462-12 standards because recently developed PV equipment has increased in demand recently due to the cheaper cost for consumers [4].

 

Conclusion

In conclusion, it is important to leave solar installation to professionals that are trained by OSHA’s standards to safely and efficiently install your solar array and even though most PV systems are designed to efficiently create energy, there can be instances of faults. These faults are the main cause of Arc Flashes that ignite solar panels and may damage the structure that they are on. First responders, much like the installers, are professionals who are trained to take the utmost precautions when shutting down and de-energizing solar panels.

 

References

[1] “UNITED STATES DEPARTMENT OF LABOR.” Occupational Safety and Health Administration, www.osha.gov/dep/greenjobs/solar.html.

[2] “Solar Construction Safety.”http://www.coshnetwork.org/Sites/Default/Files/OSEIA_Solar_Safety_12-06.Pdf.

[3] White, James R, and Mike Doherty. Hazards in the Installation and Maintenance of Solar Panels - IEEE Conference Publication, IEEE, 1 May 2017, ieeexplore.ieee.org/document/7914834/?reload=true. doi: 10.1109/ESW.2017.7914834

[4] Enrique, Eduardo, et al. Arc Flash Safety Concerns for Solar Panels. IEEE, 19 June 2014, ieeexplore.ieee.org/document/6839160/. doi: 10.1109/ICPS.2014.6839160

[5] Grant, Casey C. Fire Fighter Safety and Response for Solar Power Systems, National Fire Protection Association, Oct. 2013, www1.maine.gov/dps/fmo/documents/firefighter_tactics_solar_power.pdf.