SMA 400TL tripping RCD

[bumcrack]

SMA have also issued a letter that states that their inverters meet the exemption in the regs so that they do not require a type B rcd (if there is an rcd). There is a more complex discussion to be had on that.

Bruce,

Surely this discussion must focus on the likelihood for an IGBT to fail in such a way that it passes DC through. In other power electronics I use, IGBT's do not fail in this way. They either work, or there is a lot of carbon, and just a heat transfer plate where the IGBT used to be.

If an IGBT did pass DC it would be over in less time that would be required to trip any form of breaker...they go with a right old pop.

 

[SibertSolar]

A point to remember with TT installs is that although the regs do require an rcd on all circuits, they do not specify any value so you can make it as high as you like provided the calcs for touch voltage remain below 50V

Ah yes, I missed that valid point on my response to the other thread, thanks Bruce. And you're quite right about the best practice being to design out the requirement for an RCD in the first place. (Or don't use a TL inverter...)