westy wrote:Why would you use a breaker anyway. Use isolators and if you need protection PV fuses.
Most people use breakers since they are generally just as cheap as an equivalent isolator anyway, and there seems to be a bigger range. Are there any isolators in particular you would recommend? Especially high voltage ones?
westy wrote:This is a serious issue as a lot of TL inverters have high voltage windows. I just looked at one with 850V max
Yeah I agree. ABB make a 4 pole circuit breaker which is rated for 1600V (400 per pole) when used in this manner. The specs say 1200V, but 800V on each set of two poles is ok as long as there is never more than 1200V across it which there won't be.
It is expensive and physically quite big but can do the job for strings up to 666 Voc (800/1.2). Above that I don't know what to use.
westy wrote:Speaking direct with manufacturers, the rest of the world are not even considering this an issue. Why are we so special?
I'd like to know more about this too. In the US their standards limit PV arrays to 600V and all their inverters have to have the isolators built-in so its probably not that big an issue. In Germany I think they may not require external isolators (like Australia does) since for SMA inverters the built-in ESS seems to be ok. This only disconnects the positive leg so perhaps they only require an isolator on one pole. I'm not too sure why that is ok though...