The review concerns the pr8ne model. Code 500-37513. Good price for type A as well as for a Chinese product. Although the latter doesn't mean much since the use of Chinese materials by companies is now widespread.
This particular one requires the first phase at contact 1/2 for the test button to work...
So far, the test button only trips when phase 1/2 is present... I think that's what the diagram on it also shows...
So if for some reason phase 1/2 drops, the other two phases at terminals 3/4 and 5/6 will continue to have power without the test button working...
At least that's what I assume since I don't yet have a leakage tester for each phase...
Probably the button only tests phase 1 but the protection continues to exist internally for all 3 phases...
I still need to verify this at some point with an instrument...
I'm not an expert, I'm just describing my observations...
The truth is that at my house I used to have a similar relay, an old technology Siemens due to the panel's layout, four-pole and not two-pole, connected only to phase 5/6 in a single-phase supply and the leakage protection system worked fine...
I guess it depends on the relay regarding what it allows and what not....
Anyway, until I figured out what was going on, I did quite a bit of searching...