Ask the Expert – PV installations and DC isolators

December 2, 2024

Whether you’re navigating complex installations, troubleshooting challenging systems, or looking for guidance on the latest industry standards and technologies, Darren Staniforth, Head of Electrotechnical Solutions at CEF, is here to help.

Get the answers you need to complete your projects with confidence and precision. Ask away, and let our expert support you in delivering top-notch electrical solutions!

Question:

Is it correct to reduce the amount of DC isolators in large scale PV installations to reduce the number of possible risks associated with DC fires?

Answer:

In April 2024 a report was produced by the Fire Protection Association that looked at the installation of solar PV systems in commercial installations. It highlighted that the number of fires directly linked to PV installations is relatively low, however, its findings confirmed where fires do occur, 48% of those are related to the DC isolators.

It’s true to say a designer could reduce the fire risk by removing the isolators, but this should only be considered if the inverter allows connection of the PV strings via carefully selected solar PV connectors.

Looking closely at the problems associated with the installation of DC isolators, care must be used when selecting and installing them. Many of the problems found are considered to be:

Incorrectly sized

Lack of IP rating after installation

Lack of maintenance

A carefully selected, installed and maintained DC isolator can provide highly effective means of isolation for maintenance of the inverter, or future testing of the solar PV strings.

In conclusion, DC isolations can be very useful in solar PV systems if they are designed, selected and installed correctly. However, if an inverter has the ability to accept connection of the PV string using solar PV connectors, the designer could remove the DC string isolators from their design, thereby reducing the potential problems associated with the devices.

cef.co.uk

Need some technical advice? Darren is here to help! Send your questions to info@electrotechnicalnews.com