Ocean Deep Shocks

[Gludy]

My boat is out of the water and if I touch any metal parts such as light surrounds, ruddrs etc I am getting a hell of a shock.

Should boats out of the water be earthed? There is a main supply to it.

 

[cliffdale]

Good job Trader dont make a steel hull boat!

Try putting a volt meter negative side to Earth and probe around with the positive end of the meter. See what the potential difference is.

Whilst on the subject, why are my anodes only lasting 4 months?


Cliff

 

[PhilF]

I have never earthed mine when it is out of the water with the mains plugged in, sounds wrong and a fire hazard too, be careful

 

[Gludy]

Just measured -its 105 volts from any bit of hull metal to the ground.

The shock is large even with rubber soles on my shoes and it comes from every bit of metal on the hull.

 

[rickp]

Do you have an RCD on the boat? I wonder if this is the source of your electrolysis problem....

Definitely something to get to the bottom of whilst the boat is out.

Rick

 

[andyball]

that's a good point Rick - I wondered where the rcd was some time ago, finding just an over-current breaker where the shore-power enters the boat.

 

[Whitelighter]

RCD? Someone educate me please.

 

[rickp]

Residual Current Device - turns the power off if there is a leak. Put simply, it 'trips' if the current out of the live does not match that coming back via the neutral - because if there is a difference, the power is going somewhere else - and thats not good(TM).

Rick

 

[Whitelighter]

Thanks Rick. Next question - do I need one/should I have one already?

 

[brianrunyard]

A residual current device (RCD), or residual current circuit breaker (RCCB), is an electrical wiring device that disconnects a circuit whenever it detects that the flow of current is not balanced between the phase ("hot") conductor and the neutral conductor. The presumption is that such an imbalance may represent current leakage through the body of a person who is grounded and accidentally touching the energized part of the circuit. A shock, possibly lethal, is likely to result from these conditions; RCDs are designed to disconnect quickly enough to prevent such shocks.

 

[Pete7]

Your getting mains electricty thoughout the boat /forums/images/graemlins/blush.gif I would up plug it, tell Trader before someone electricutes themselves and book into a B&B. There is a public footpath through there yard, anyone could be a bit too nosey and get quite a shock

Pete

 

[cliffdale]

We are assuming it is mains. Its difficult to tell whether it is alternating current or direct current without an oscilloscope. What happens when you disconnect from the mains supply?

There are plenty of ways 12.8v can be generated up to 105v

 

[A_8]

Something is seriously wrong and needs fixing. If your boat is CE marked I think it needs a RCD breaker.

 

[thailand69]

It is NOT normal.

I don't know much about electrickery but if this was my boat and she was plugged into the mains then this would be the first thing I switched off. I would also be minded to take off any expensive electronic toys.

Apart from the risk of Electrocution I would also assume a possible fire risk.

I would get a proffesional in before she catches fire, unless............ /forums/images/graemlins/shocked.gif /forums/images/graemlins/grin.gif

 

[steverow]

Paul,

This looks like some kind of phase problem with the shore feed.
I'm sure Chris will know the exact answer.
It is however very dangerous so stay off the boat for now until trader have fixed it.
I mean that by the way...you can easily electrocute yourself or Lesley under those conditions.

 

[lanason]

Surely the shore power is sngle phase not triple ???

Sounds bad to me time to disconnnect fast IMHO

 

[halcyon]

Just a point, 105 volt can kill you, if you have a little bit of current.
From my days of designing fork trucks 70 volt is the upper safe voltage, though I do not offer warrenty.

105 volt sounds like half wave mains volts.

Un plug it.

Brian

 

[Garryt]

You may need a Galvanic Isolator.

See here:

http://www.yandina.com/galvanicIsolator.htm

Garry

 

[steverow]

Yes it will be but I suspect the supply to the yard will be three phase...so it depends on how the supply has been wired.
Having had this sort of problem before at school, 105 volts sounds just about right for a phase issue.

 

[ms1]

no contest surely,
Un plug and get advice