The Extra Cost Of Transformerless (TL) Inverters
As the solar industry evolves, more information, incidents and regulation changes have effected how the industry is improving. I’m going to discuss one change to regulations which may effect you.

If your inverter stops working and you want to replace it, there’s a chance you’ll be up for more than the cost of a new inverter. In summery, if you have what’s called a “Transformer based inverter” such as an Aerosharp or Fronius IG Series and the only replacement suitable for your panels is a “TL” (TransformerLess) inverter, you will have to pay additional wiring costs to bring your solar panel array/s up to regulation.

All solar panels and framework require earthing when installing a TL inverter.


The additional wiring cost of replacing a transformer based inverter with a TL inverter may be anywhere from $600 to over $1000 to earth your panels and framework and bring your solar system up to regulation. This is over and above the price of the new inverter. The additional cost is in direct relation to the number of panels requiring earthing so the more panels you have, the more it will cost you.

Here’s a diagram of what we’re talking about…


If the only viable replacement for your transformer based inverter is a TL inverter then yes, you do need to upgrade the wiring and earth the panel array/s. There is no getting around it. It needs to be done for safety reasons to prevent the panel array/s and framework becoming live in the event that the TL inverter fails and causes electricity to flow back potentially electrifying the panel frames and mounting rails.


Wherever possible, we replace broken transformer inverters with Fronius Galvo because they too are transformer based. However if your system has a transformer inverter and it fails, the situation may occur where we have to install a TL inverter due to panel DC voltages that the Galvo can’t handle. In this case there is no question, you need to have the additional wiring done to make your system safe.

It’s a horrible situation for people to be in. Not only are customers up for the cost of a new inverter, they may also need to pay for the additional wiring which negates any savings on electricity your solar system was installed for.

We can offer advice on the best option should your inverter fail. Where possible, we’ll install a Fronius Galvo to remove the need to earth your panel array/s. However if a replacement requires the use of a TL inverter, we can organise the additional wiring needed and guide you through the entire process.
I hope this information has helped.


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