Quote:
Originally Posted by luggsey
Not really! Most generators I have tinkered with don't have a centre tap, that's the point.
They simply provide a floating supply with no earth reference, that's why I mentioned being careful with an installation that uses an RCD for shock protection, they don't normally work on floating supplies like small generators or invertors.
This catches people out because they test the RCD with a mains hook up and the RCD works, many don't realise it's not going to work on the invertor!
The type of sine wave on the invertor doesn't effect the floating supply output, it's still a floating (or two phases as I describe it because I think that's a clearer way to describe it) supply.
If you want an invertor with RCD protection its going to be easier to buy one with a built in RCD and an earth connection which will be already internally connected between neutral and earth like a centre tapped and earthed generator can be.
It really is a can of worms.
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I think I get what you're saying...
However I don't see why an RCD shouldn't work on a split phase/2 phase/floating supply as opposed to conventional, fixed mains?
The RCD should trip if the leakage current exceeds 30mA (or it's rating) - i.e. if the difference in current between the live and neutral conductors is > 30mA because some of the current is taking an alternative path.
The problem with temporary installations such as a caravan is creating that alternative path... Faults within appliances with a case earth will trip the RCD in the same way but simply touching a live conductor is unlikely to create sufficient leakage to trip the RCD unless you are touching something else that will create that path. Hence it's better to earth bond the chassis, sink, cooker, water and gas pipes/systems etc.
I have found some guidance on it:
http://www.hse.gov.uk/foi/internalop...99/oc482_2.htm