Genny stuff again,,soz

[wattsup]

Well the latest I installed, 10kva...instructions regards earthing
this genset has a floating earth...no probs ok, yeah I know.

If providing power via rcd on consumer side, a link wire should be placed on the supply ouput of the genset neutral to earth, with a warning 'not for use other than mains supply, 'Neutral Earth Link Fitted'.

Further reading of installation instruction, says, the supply from the gen set should be the same earth config of normal supply. Ok I get that.

So on power up to test, the rcd still works on the consumer rcd without neutral earth link supply from genny, the genset has a conventional 40a isolator mcb.

So I don't get the point of the link. The gen is start auto on mains failure, in effect the genset is the supply authority. I don't get how the rcd still works without the link...Anyhow still fitted later as per instruction.

I have installed several over the past few months, but this is the first auto start (most people just do with a normal transfer switch)
The installation procedure for this set was more involved than normal, Briggs and Stratton, even though more or less exact same to do (just connect into auto switch gear rather than manual switch gear. No difference really except the price of the friggin unit!

Anyhow because the set seemed at first to be more complex I read installation instructions thoroughly, not least because the set cost 6k and did not want to invalid warrenty etc

Anyhow I'm now left wondering if I should have installed a neutral earth link on all jobs i've done in the past few months? No problem to go back and do, I can easily go back to all for a 'free' maintainance check, and stick one in if need be. I've gone over all installation manuals for previous but can't find anything regards the earth neutral link?
Am I wasting sleep over this?

I've installed massive stuff in the past, but of course for others as a worker, boy I wish I'd taken more interest. Maybe if I did, I would know what I'm doing now -

It is only now I realise why some gaffers seemed misserable, they must have been wondering...can it cope with load...does it need an earth link...will them *******s turn up on sunday to test...

 

[Carter]

Just thinking out loud here, gensets not my forte really but there has to be some sort of return or leakage path or it wouldn't trip. Any fortuitous/incidental earth paths? final cct neutrals? Maybe it's acting as an insulation resistance monitor across L/N and E, a fault in insulation between live conductors and installation earths? do the IR readings check out OK?

 

[wattsup]

earth tests all ok.
earth spike at genny good, genny frame good, bonding, water etc (except a plastic water supply, so bonded at consumer side), no gas just oil which is bonded to earth bar. All earthing in the house is ok. No problem, the house is only 3-years old. They are prone to power cuts, big ones, last winter several, the biggest being 7-days no power. That is by-the-by..but no installation probs electrical, no earth neutral faults etc. The RCD still worked without link E - N on the genny output supply, this is a brand new genset and tested with a floating earth....so I don't get it

 

[spark-doctor]

When you say the RCD worked, do you meen it tripped when you pushed the test button?