Conundrum clarification

BirvidikBob

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Many thanks to all who have so far commented. I’m afraid that I sacrificed clarity in a futile attempt at brevity.

I don’t know how to attach a diagram so here (I hope) is a clearer description of the protection:

The live from the shore power (brown) feeds into a single breaker (a Hager 15A type 2M3). The output from this feeds into a second breaker (a Hager 240U 40A). The return (blue) from the shore power also feeds into this. Output from this goes to the boat as previously described.

Shore power voltages (sorry, I should have mentioned these in the original post):

Live to Neutral: 228v
Live to Earth: 16 v
Neutral to Earth: 212v

It wasn’t a static shock as it recurred immediately if touched again.

The meter is an MY68 digital multimeter, about the size of a housebrick, not one of your dinky little cheapo jobs.
 

Bru

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I have PM'd the OP about this in detail - the situation is potentially lethal

(I suspect the incoming supply is mis-wired and also that there is no earth leakage protection)
 
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Plevier

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I agree with Brigantia and am going to withdraw from any attempt to resolve it remotely.

I can only suggest disconnecting and getting it looked at by someone qualified, with urgency.
 

sarabande

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check your insurance immediately, especially the bits about 3rd party liability. How on earth (sorry!) the wiring has got into that situation without killing anyone is amazing.

Whoever controls the shore side must be told ASAP, and sort it out, as there may be other boats in a similar situation.
 

prv

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Live to Neutral: 228v
Live to Earth: 16 v
Neutral to Earth: 212v

That is very, very bad. Don't even think about using that supply any more, under any circumstances, until it has been checked, diagnosed and sorted. And tell everyone else you can, because there is a real chance that someone is going to die.

I agree that there's something screwy going on with the boat installation, which needs to be carefully checked as a matter of urgency. But just focussing on those voltages, is it not simply a case of reversed polarity? Very wrong under UK rules, but I believe other countries (the boat's in Turkey, right?) are often less picky and have wiring designs that can cope. Look at all those 2-pin plugs that can be inserted either way round, for instance.

Pete
 

Bru

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Pete is right in that the measured voltages are suggestive that the live and neutral are reversed.

However, whilst at the wall socket on many continental electrical systems you have a reversible 2 pin socket / plug arrangement that doesn't mean that the incoming supply is necessarily tolerant of swapped polarities or that it is by implication acceptable (in Turkey or anywhere else) to swap the live and neutral wires in the wiring to a socket connection. It just means that many appliances don't care which way round they are connected

I would be surprised if it was considered acceptable practice in Turkey (or anywhere else with a single phase supply) to swap the live and neutral conductors in the wiring to a 3 pin (L-N-E) supply socket - somewhere down the supply line neutral is normally bonded to earth or connected to ground (unless it is an IT power distribution network but that would be a VERY odd thing to have running into a boatyard in Turkey or anywhere else for that matter - down a coal mine or into a high security communications ... oops! Forget I said that!!!!)

What is worrying is that the voltages measured are suggestive of very poor earthing. I've relayed my suspicions on this to Bob by more detailed PM but with lots of caveats because whatever the fault may turn out to be, the plain fact is that we cannot safely diagnose this fault remotely from thousands of miles away and the very best, and really only, advice is for Bob to get the system checked out in person by someone with the relevant expertise

Hmmm, there is one other situation where IT power distro is "normal" ... if the supply is being run off a local generator set and there is no ground spike bonded to earth on the generator - this is exactly what most of us do when we fire up a portable generator of course. All along I have been assuming that the power source is an incoming feed from a power distributor ... perhaps Bob should check this out. If the boatyard is running of it's own big generator buried in some shed out the back and that genset has no ground spike (or a ground spike that's no longer making a good ground connection) .....

Bru
 
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