What Is A Solar Isolation Switch and Is It Necessary?
The isolator in a solar power system has the job of closing down the electrical current from flowing through the circuits in the system.
This function operates as a switch that is specifically designed for safety in times when maintenance is required on solar systems, or in cases of emergency.
The solar isolator works as a safety device that operates as a mechanical switch in that it physically disconnects the electrical circuits of the solar panel array from the rest of the system.
Solar isolation switches do not simply interrupt the flow of current. This makes them different from the way that other electrical switches would normally operate wherein the switch simply interrupts the current. Here there is a complete and absolute disconnection from one circuit part to another.
By design, an isolator creates an air gap when it is in the open (off) position. This air gap is a fundamental feature of an isolator’s operation and is crucial for its safety function.
There are two types of isolation switches that are commonly used for this purpose, rotary switches and knife switches.
Rotary switches are straightforward to operate, providing a clear and intuitive way to open and close the electrical circuit. The rotary action moves contacts within the isolator to open or close the circuit.
Rotary switches are often encased in weatherproof enclosures protecting them from rain, dust, and other environmental factors. This creates a secondary level of safety in its longevity and the reliability of its function.
The knife isolator is an older style of isolation switch. It operates via a simple mechanism of having a very mechanical design whereby a metal blade (contact arm) is manually inserted or removed from the connection through which the current would flow.
The simplicity and visibility of the knife switch made this a good choice in the earlier days but these days it tends to lag behind the rotary isolator due to its safety factors. One of the reasons is that knife switches expose live electrical parts when open. This can leave the service person exposed to electrical currents creating a serious hazard.
Placement of Solar Panel Isolators
In solar installations, isolators are typically placed on both the DC side (between the solar panels and the inverter) and the AC side (between the inverter and the home/grid connection).
Although isolation switches are necessary for maintenance workers to operate safely, if not checked, the isolation switches themselves can fail due to lack of service.
How Can Isolation Switches Fail:
Use of Low-Quality Switches: When switches of inferior quality are installed, they are prone to either seizing up, making them difficult or impossible to operate. Additionally melting can occur due to the use of substandard internal components unable to withstand the electrical load or heat.
Improper Sealing of Weatherproof Isolators: Isolating switches that are designed to be weatherproof can fail if they are not sealed adequately. Ingress of water into the switch can lead to electrical arcing and can generate hotspots.
These hotspots can lead to the switch melting in less severe cases. In more extreme scenarios, this condition presents a real risk of fire due to the excessive accumulation of heat inside the switch.
These issues underscore the importance of using high-quality, appropriately rated isolation switches and ensuring proper installation and maintenance to prevent such failures.
You can rely on our team of experienced A-grade electricians at The Solar Repair Man to ensure your solar system is operating at optimal levels.
Narre Warren
Call The Solar Repair Man on 1300 432 234
Or visit the website at: https://thesolarrepairman.com.au/
