I don't understand what you are talking about. If the CPC were not connected to the appliance (which it wouldn't/couldn't be with a Class II one), then spindles & bearings etc. are surely irrelevant.With a three core cable with earth not connected at appliance we have a number of issues. ... 1) How can you test the earth? I have when testing in service electrical equipment already come across the problem of testing. Often the only part which can be accessed is the spindle and 25 amp through a bearing is not a good idea. To test the earth I will use the IT setting so as not to damage the bearings but with a welders extractor fan it still needed some stripping to be able to test.
If the CPC were only there in case the cable was severed, I'm not sure that it would really need to be tested. Don't you have to check that an appropriate sized fuse (and not a nail) is present in the plug, whether there is a CPC or not?To have to disassemble the handle on the appliance to test earth as well as the plug to check on fuse size would increase the cost of testing.
You are merely repeating the uncertainties/questions I posted earlier. I agree that an RCD might well not operate in response to a very transient fault, particularly if it occurred around the time of zero crossing of the waveform. However, having a CPC certainly increases the chances that some protective device would operate - I have certainly had an RCD (but not any OPD) operate when I've cut a cable.2) Would it actually trip if cut? Consider even a slow hedge cutter maybe an inch movement and the cable core is around 1/16 inch at 375 strokes per minute that means maximum contact time of 1/100 second or 10 ms and the RCD needs 40 ms to operate. So even with an earth wire included it is unlikely to operate a RCD.
I think that you are 'scraping the barrel' a bit there!3) The cable would be heavier and thicker and more prone to damage when coiled.
Fair enough - we'll have to disagree about that. I am personally in favour of anything which reduces, even if only a bit, the chances of injury/death resulting from what seems to be a pretty common 'incident' with electrical garden tools.So I see little point in using three core cable.
That's just not going to happen any time soon with domestic garden tools - and would only happen at all if it became mandatory.If you want to make it safer then have a 55-0-55 transformer and a 110 volt lawn mower. But unless made law can't see anyone using one.
I think that's because they were essentially useless - although they might be more viable now that there have been developments in battery technology.There were battery lawn mowers mainly cylinder type but not seen them for years.
Kind Regards, John