Shoreline safety issue.

[IanD]

1 minute ago, David Mack said:

My electrical engineering supervisor related the tale of someone he knew who would deliberately place a finger tip on suspected live metalwork, and after a couple of moments would pronounce "Yes, that's live."

In similar circumstances I've always used the slightest brush with the back of a finger, so if it is live the reflex muscle action pulls the finger away from contact.

Indeed -- and that's also why you should use your right hand, to try and keep any current through the body away from the heart... 😉 

[David Mack]

2 minutes ago, IanD said:

Indeed -- and that's also why you should use your right hand, to try and keep any current through the body away from the heart... 😉 

Not for Norman Swift, that I sang with in choirs years ago. His internal organs were all a mirror image of the normal arrangement, something he only found out when he had an army medical for his National Service.

[StephenA]

6 minutes ago, David Mack said:

Not for Norman Swift, that I sang with in choirs years ago. His internal organs were all a mirror image of the normal arrangement, something he only found out when he had an army medical for his National Service.

 

Are you sure it wasn't just his head was on backwards?

[IanD]

10 minutes ago, David Mack said:

Not for Norman Swift, that I sang with in choirs years ago. His internal organs were all a mirror image of the normal arrangement, something he only found out when he had an army medical for his National Service.

Also a problem for The Doctor... 😉 

[jonathanA]

48 minutes ago, IanD said:

Nope, because there's no AC voltage on the neutral to drive >30mA current to earth through the body... 😉 

 

(or at least there shouldn't be, with N-E bonding somewhere nearby...)

 

And if the current flows from L-N through your body, that might not trip either -- though it will if there's enough current from your "live" hand to GND through parasitic leakage.

 

 

nope just wrong....  I've had RCD trip many many times when i've just touched the neutral or let a bare neutral touch something earthed, with the phase disconnected at an MCB, fuse or single pole switch. I haven't imagined those trips i can assure you.  it only needs a very small voltage on the neutral to reach 30mA.  

 

its not unusual for there to be a few volts (or indeed quite a few volts) between neutral and earth. I would expect this to be very much the case at a marina where the N/E substation bond could be a long way away. In any case it would almost certainly be a TT earth system as opposed to a PME (TN-C-S) system, so there could be quite a voltage difference between the neutral and local earth/real earth.  

 

there is a risk is that the local earth is not good enough for a 30mA rcd to trip in the required time although a marina install should be properly designed and regularly tested, i rather suspect some of the shall we say less formal moorings may have less than ideal electrical install or installs that are not regularly inspected or tested.  

 

Having seen quite a few failed RCDs i agree sticking your fingers in isn't a good option and you can't always rely on them to work, one day when its raining and your stood in a puddle with wet feet it won't trip and its half a day out with the undertaker... 🙂  (and you should have tested it 😟)

[IanD]

11 minutes ago, jonathanA said:

nope just wrong....  I've had RCD trip many many times when i've just touched the neutral or let a bare neutral touch something earthed, with the phase disconnected at an MCB, fuse or single pole switch. I haven't imagined those trips i can assure you.  it only needs a very small voltage on the neutral to reach 30mA.  

 

its not unusual for there to be a few volts (or indeed quite a few volts) between neutral and earth. I would expect this to be very much the case at a marina where the N/E substation bond could be a long way away. In any case it would almost certainly be a TT earth system as opposed to a PME (TN-C-S) system, so there could be quite a voltage difference between the neutral and local earth/real earth.  

 

there is a risk is that the local earth is not good enough for a 30mA rcd to trip in the required time although a marina install should be properly designed and regularly tested, i rather suspect some of the shall we say less formal moorings may have less than ideal electrical install or installs that are not regularly inspected or tested.  

 

Having seen quite a few failed RCDs i agree sticking your fingers in isn't a good option and you can't always rely on them to work, one day when its raining and your stood in a puddle with wet feet it won't trip and its half a day out with the undertaker... 🙂  (and you should have tested it 😟)

I don't think we're disagreeing here -- like I said (and you did too...), it all depends on where the N-E bonding is done -- and what the supply impedance is, as well as the impedance of "the body" (including how wet everything is). The RCD might trip if you touch the neutral or might not.

 

But except to argue for the sake of it (which *never* happens on CWDF, oh no!!!) it doesn't really matter anyway, the key point is that you shouldn't have exposed live pins with an unplugged shoreline lead, either at the boat end of the lead (shore feed) or the connector on the boat (e.g. if onboard inverter is running -- this is why back-feed to the grid is banned).

 

And as you say RCDs should be tested regularly, to prevent unplanned undertaker visits... 😉 

Edited July 27 by IanD

[stagedamager]

A surveyor we know failed several boats for having "widow makers" and was told to pass them when people complained. We refuse to work on any boats with widow makers, and i know of several other yards who take the same stance. 

[David Mack]

17 minutes ago, stagedamager said:

We refuse to work on any boats with widow makers, and i know of several other yards who take the same stance. 

Do you take on the job to rectify the situation?

[jonathanA]

40 minutes ago, IanD said:

But except to argue for the sake of it (which *never* happens on CWDF, oh no!!!)

surely not....  

 

i agree we are agreeing to not disagreeing.... 

 

its not just shore leads, you do see 13A plug top to plug top leads so that numptys can plug their generator/inverter into their mains wiring and not just on boats....   or as @stagedamager calls them widow makers.   There was someone on here who claimed to always cut up any leads like that - can't recall who it was.  

[stagedamager]

1 minute ago, David Mack said:

Do you take on the job to rectify the situation?

in my experience they tend to be owner self fit outs, and once you start looking the job has "scope creep" so whilst it could be a case of swapping to a 16a bulkhead plug, these things rarely are..... 

[David Mack]

Just now, jonathanA said:

There was someone on here who claimed to always cut up any leads like that - can't recall who it was.  

Just cutting them leaves usable plugs with bare wire ends, which could be touched. Better to unwire the plugs completely, albeit that it takes longer.

[Momac]

6 hours ago, Cheese said:

So it is understandble how DIY fitters sometimes get it wrong.

You could buy two household plugs and make an extension lead with a plug at each end . Would anyone even think of doung that? I hope not.       For some reason people can become confused when it comes to shore power for boats and cravans. 

I met someone who had the live pins arrangement on a DIY extension cable for his boat shore power but he did not believe me that it was unsafe despite the cable delivering shocks when the live pins were exposed.

 

At least the BSS examination should fail a back to front shore power inlet installation rather than it being an advisory.

 

[David Mack]

1 hour ago, Momac said:

At least the BSS examination should fail a back to front shore power inlet installation rather than it being an advisory.

Since the BSS is supposed to be about safety for others, rather than the boatowner, the BSS should indeed fail such an arrangement, since a widowmaker shoreline unplugged from the boat and left on the bank could be touched by a passer by (curious child or perhaps dog).

[jonathanA]

1 hour ago, Momac said:

You could buy two household plugs and make an extension lead with a plug at each end . Would anyone even think of doung that? I hope not.

See my post  3 posts back.... I've seen secondhand generators sold with leads like that I kid you not....

[Russ T]

18 minutes ago, David Mack said:

Since the BSS is supposed to be about safety for others, rather than the boatowner, the BSS should indeed fail such an arrangement, since a widowmaker shoreline unplugged from the boat and left on the bank could be touched by a passer by (curious child or perhaps dog).

I don't recall a bss inspector ever checking we have the incoming ac earth wire bonded to the hull either,which is cleary a potential danger to a third party. 

 

Having said that,I may just have not noticed him checking.

[GUMPY]

So long as you unplug the cable from the supply first where's the problem 🤔🫢🫣

[David Mack]

5 minutes ago, GUMPY said:

So long as you unplug the cable from the supply first where's the problem 🤔🫢🫣

As long as the installer hasn't used an appliance inlet on the bollard...

[Jen-in-Wellies]

19 hours ago, jonathanA said:

surely not....  

 

i agree we are agreeing to not disagreeing.... 

 

its not just shore leads, you do see 13A plug top to plug top leads so that numptys can plug their generator/inverter into their mains wiring and not just on boats....   or as @stagedamager calls them widow makers.   There was someone on here who claimed to always cut up any leads like that - can't recall who it was.  

The major ecommerce platforms, Ebay, Amazon, Aliexpress etc, were selling these things until relatively recently. I couldn't find any on a quick search, so the ban seems to be working. Now anyone with a death wish has to make their own. 

 https://www.cpsc.gov/Newsroom/News-Releases/2026/CPSC-Warns-Consumers-to-Stop-Using-Male-to-Male-Extension-Cords-Secures-Delisting-Commitments-from-e-Commerce-Platforms

[cheesegas]

27 minutes ago, GUMPY said:

So long as you unplug the cable from the supply first where's the problem 🤔🫢🫣

How about if it’s someone who’s not you unplugging it? Or it comes unplugged by accident? 
 

Absolutely no reason to just remove the human factor entirely and fit the correct part. 

[IanD]

1 minute ago, cheesegas said:

How about if it’s someone who’s not you unplugging it? Or it comes unplugged by accident? 
 

Absolutely no reason to just remove the human factor entirely and fit the correct part. 

Did you miss out a "not"?

[Jen-in-Wellies]

Plug in balcony mount solar panels have been approved for the UK. Common in Germany and some other European countries for years. These do use a normal looking 3 pin male plug to supply power to the home. Obviously there is all sorts of clever stuff going on to match the grid phase and to disconnect reliably if the plug is pulled out, so the pins aren't live unless covered. However, seeing these, a lot more people are going to think having male pins on the supply side is fine, because. 

[IanD]

Dangerous connectors...

 

Edited July 28 by IanD

[David Mack]

1 hour ago, Jen-in-Wellies said:

Plug in balcony mount solar panels have been approved for the UK. Common in Germany and some other European countries for years. These do use a normal looking 3 pin male plug to supply power to the home. Obviously there is all sorts of clever stuff going on to match the grid phase and to disconnect reliably if the plug is pulled out, so the pins aren't live unless covered. However, seeing these, a lot more people are going to think having male pins on the supply side is fine, because. 

And because they rely on the socket having a mains supply to match phase, they aren't any use in a power cut!

[Momac]

 

It seems not many people die from electrocution in the UK so I think those of us with correctly fitted shore power inlets and cables may be in an even lower risk category compared to those with the potential live pins arrangement. 

 

Perhaps it would be wise never to volunteer to disconnect a shore power cable for another boater.

 

As already suggested there is  arguably some extra element of safety in disconnecting the cable from the shore power bollard before disconnecting the cable from the boat. And of course  first connect the cable to the boat before connecting to the shore power bollard. The shore power bollard cannot possibly be provided with a  live pins fitting (I hope).

 

 

[Jen-in-Wellies]

9 minutes ago, Momac said:

The shore power bollard cannot possibly be provided with a  live pins fitting (I hope).

Be prepared for someone, somewhere, to prove you wrong!