How do I protect my solar installation from lightning?
Mar 1st 2022
Grounding and making your system safe
Lightning can pose a big threat to your solar installation if you don’t implement the proper safety, protections and grounding systems. If lightning hits your solar panels, a catastrophic surge can occur, making lightning the number one cause of catastrophic failures. However, it’s important to know that you can protect your system by putting in the proper ground technology and procedures.
How do I ground my solar installation?
You can’t prevent lightning from hitting your solar equipment, but you can give it a direct path to the ground. Panel frames and mounts should be grounded in order to provide the easiest path for lightning to get to the ground. Grounding is the most fundamental way to protect your system from lightning damage. An electric path to ground will also discharge static electricity that accumulates above ground. We recommend installing your grounding system before or while you are installing the rest of your solar installation.
Lightning arrestors and surge protectors can also be used to protect electronic equipment by absorbing electrical surges. However, keep in mind that they’re not a good substitute for grounding. In an ideal setup, they function in conjunction with effective grounding.
What happens when lightning strikes a solar panel?
When lightning directly strikes a panel, it can melt the panel or inverter. Indirect strikes will induce high voltages into the system and break down conductors, PV panels, and components. They’ll also produce dangerous sparking that could ignite combustible material.
Do solar panels attract lightning?
No, solar panels do not attract lighting. Putting solar panels on your roof will not increase your home’s risk of getting hit by lightning.
What does grounding do?
Grounding fulfills some essential functionalities, including:
Yes, solar panels continue to improve in efficiency. In 1954, the first useful silicon solar panel produced by Bell Labs was about six percent efficient. Technology has evolved at a rapid pace and continues to improve. In fact, researchers have managed to achieve almost 50 percent efficiency in laboratory tests. Currently they aren’t cost effective to produce, but that day may be in the near future.
What’s in a grounding system?
There are two main grounding system types, equipment grounding and system grounding.
1.Equipment grounding:
This is the more traditional and visible form of grounding. Any metal or potentially conductive materials that are likely to be energized in the system must be grounded. Equipment grounding is known as safety grounding or protective earthing.
2.System grounding: In system grounding, one of the circuit (current-carrying) conductors is connected to the equipment grounding system and also to earth. This is known as functional grounding. In system grounding, one of the two conductors coming out of the PV system will be grounded, typically the negative wire. System grounding will also include a ground fault fuse to prevent fires within the system from excessive current flowing into the ground.
What are the different grounding types?
You may be familiar with a single metal grounding rod, but there’s a range of other grounding options available.
1.Single Point Ground: In this scenario, a ground wire connects to a ground rod or ground wire under the electric meter.
2.Ring Ground: A #2 AWG bare wire is buried a minimum depth of 30" in the soil encircling a structure.
3.Ufer Ground:
In this type, metal bars that are encased in concrete and buried a few feet under ground. This is used when terrain or other physical barriers prevent single point grounding.
4.Isolated Ground: This is a separate, insulated safety ground wire that connects an equipment cabinet to the nearest ac distribution neutral-ground bond. It is used to maintain isolation from building conduit, which can conduct high frequency noise during an electrical storm.
5.Halo Ground:
This setup consists of bare or insulated wire and runs around the ceiling of a structure and connected to the corners of a buried ring ground.
Is a single grounding rod enough?
Typically, a single 6 to 8 foot ground rod is not enough. You may have to use 2-3 10-foot rods, all bonded together with #6 wire and copper wire clamps. However, if you cannot do this, something is better than nothing. In some cases, you may have to go so far as to bury lengths of bare copper wire or copper pipe in trenches.
How do I ground my system?
YTo give you an idea of what a grounding system can look like, here’s a breakdown of what a single rod installation can look like.
1.First you’ll drive a grounding rod at least eight feet deep into the earth near your solar installation.
2.Leave around 6” above the ground to properly attach your wiring to the grounding rod. You can typically use a thick, bare copper wire to handle large electric currents like lightning.
3.Run your wire up your pole mounting system and attach it to a grounding screw.
4.Wrap the wire around the grounding screw and tighten the bolt. Trim off any excess wire.
What are arrestors and capacitors?
Surge Arrestors act like "clamps" in most cases. They offer a discharge path to the earth, rather than allowing current to flow through your electronics. Surge arrestors go across live wires and then, if the voltage goes above a certain level, they will shunt the higher voltage to ground.
Surge capacitors catch high voltage spikes on the AC line that are too fast for the surge arrestor to catch.
Do fuses and breakers protect me from lightning strikes?
No, fuses and circuit breakers offer no protection to lightning strikes. That is not their purpose. Lightning usually lasts for only a few microseconds - much faster than any fuse or breaker can blow.
How much does it cost to ground your system?
A home lightning protection system can cost anywhere between $500 and $2,500. The system consists of one or more lightning rods, a grounding system, wiring, and a surge protector.
Conclusion
Grounding your solar installation is a great way to protect your home in case of lightning and storms. Lightning can be catastrophic for your installation, and while grounding systems are an added expense, the peace of mind of having a protected system is priceless.
