Reverse Polarity DC Breakers

Breakers & Isolators

Solar DC Isolator Inspections

Many people who own solar systems in the Ausgrid territory have received inspections (or inspection notices) relating the polarity of DC Isolators and/or DC breakers.

-> What is a breaker

All professionally installed solar PV systems include a switch or breaker on the wires running from the panels to the grid connect inverter.

Located next to the inverter, this switch is usually labelled PV Array Main Switch or Solar DC Isolator. It is also known as a DC breaker, a DC isolator, a solar switch or a trip switch.

Whilst in small systems incorrect wiring (polarity) may not pose a danger, incorrect wiring of the breaker stops the ‘arc suppression’ functions of the isolator from working. In larger systems, if the incorrectly wired breaker is operated whilst the inverter is producing power, the breaker can burn out.

In most cases the breaker is inspected and found to be without issue. In a minority of cases, issues are identified and the system shutdown.

What to do if your solar system has been shutdown by inspectors:

If your system has been shut down, contact the company that sold you the system and request that they remedy this problem.

What if I don’t know who installed the system?

With some systems, the installation was done some time ago and records have been lost, or the original contractor cannot be located.

Contact Greenforce Energy on 02 9557 1648 to discuss how to proceed.

If you have not been inspected, but are concerned about your system, Greenforce Energy currently offers discounted rates for testing and evaluation of your solar generation system. We call this solar panel inspections 

What is the cause of the problem?

The cause of the problem is that it was not adequately spelled out to some installers that the markings on the breaker referred to the wires coming from the panel (panel is the source). Since the inverter is connected to the grid, and the electricity grid is treated as the source for most AC wiring, a minority of installers mistakenly connected to the breaker using the polarity of the inverter. This problem is outlined in the Discussion Paper – Correct Wiring of Double Pole DC Breakers