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Live - Neutral Reversed


Nobag

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1. No proper earth connection.

2 Wear and tear of leads and sockets

3. No strain reliefs on leads.

4. Swapping leads in the rain

5. The possability that one or more power sources is not properly earthed so the RCD can not trigger.

( The test button on the RCD only checks the RCD internal function, it does not check for missing Earth or N-E bond whithout which the RCD is of no use.)

6.Leads not fused.

7. Inadequate lead gauge

And so on...

 

Ofc some of this can be prevented, still leads are not for permanent use.

 

I can't accept that any of these are valid. All of them can be prevented with ease.

 

1. The boat's electrical system can be bonded to earth. The inverter's earth and neutral can also be bonded to earth The incoming earth from the shore line, via a GI, connects to the earth connection of the socket. Thus everything is safely earthed at all times.

 

2. Sockets are designed to be plugged in and out. These would be operated relatively infrequently and would not wear out. The cable would be flex which is designed to be a flexible connector to a plug, there is no reason why it should suffer wear and tear.

 

3. Then fit strain reliefs where necessary. For example a cable clip.

 

4. Whyever would you mount your sockets within reach of the rain?

 

5. Each power source should have an RCD. The use of a switch or of sockets makes no difference to how they operate. For example the shore line through a consumer unit feeding one socket, with the other socket (fed by the inverter) being in itself an RCD socket.

 

6. The 13A plug has a fuse in it.

 

7. Then use the correct gauge of wire when installing it.

 

And so on.

  • Greenie 1
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Would be best to double check with a filament test lamp or suitably skilled eleccy person before proceeding any further.

 

I suspect the Maplins inverter is supplied without NE bonding, maybe the MSW output waveform gives an unexpected tester result with no earth?

 

So does a suitable test lamp illuminate if SAFELY connected between N and E or L and E of the inverter socket?

 

IF neither, then it's lacking an NE bond, and a clearly labelled and suitably wired plug and socket could provide this.

 

Another way to help check the existence of a functioning earth is connect a suitable test lamp between L and E downstream of the RCD.

 

cheers, Pete.

~smpt~

I have been loaned a Megger mft1552 to test the earth and rcd.

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I can't accept that any of these are valid. All of them can be prevented with ease.

 

1. The boat's electrical system can be bonded to earth. The inverter's earth and neutral can also be bonded to earth The incoming earth from the shore line, via a GI, connects to the earth connection of the socket. Thus everything is safely earthed at all times.

 

2. Sockets are designed to be plugged in and out. These would be operated relatively infrequently and would not wear out. The cable would be flex which is designed to be a flexible connector to a plug, there is no reason why it should suffer wear and tear.

 

3. Then fit strain reliefs where necessary. For example a cable clip.

 

4. Whyever would you mount your sockets within reach of the rain?

 

5. Each power source should have an RCD. The use of a switch or of sockets makes no difference to how they operate. For example the shore line through a consumer unit feeding one socket, with the other socket (fed by the inverter) being in itself an RCD socket.

 

6. The 13A plug has a fuse in it.

 

7. Then use the correct gauge of wire when installing it.

 

And so on.

^^^^^^

 

All this.

 

I can't see any your reasoning applies, if it is done properly.

 

It is just as easy to wire a fancy switch badly, as it is to do so with a conventional plug and socket.

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Common sense is a flower that doesn't grow in everyone's garden. Might I suggest that if the OP is unsure then go to the people who are insured to tell you. Explaing this to someone who competence level may only be operating a retractable ballpoint pen will end in tears.!

 

No offence OP

Edited by Maffi
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In addition, of all the shocks I've had so far in my life none has a ) killed me or b ) caused the RCD in the house to trip.

 

I still don't think 240Vac is a Good Thing to have in a boat though...

 

MtB

I have the same experience regarding mains shocks.

I think I wired my office down the garden the wrong way round somehow because when I switch it off at it's local consumer unit I still get a shock from the light fittings. Everything works fine though.:

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I can't accept that any of these are valid. All of them can be prevented with ease.

 

1. The boat's electrical system can be bonded to earth. The inverter's earth and neutral can also be bonded to earth The incoming earth from the shore line, via a GI, connects to the earth connection of the socket. Thus everything is safely earthed at all times.

 

2. Sockets are designed to be plugged in and out. These would be operated relatively infrequently and would not wear out. The cable would be flex which is designed to be a flexible connector to a plug, there is no reason why it should suffer wear and tear.

 

3. Then fit strain reliefs where necessary. For example a cable clip.

 

4. Whyever would you mount your sockets within reach of the rain?

 

5. Each power source should have an RCD. The use of a switch or of sockets makes no difference to how they operate. For example the shore line through a consumer unit feeding one socket, with the other socket (fed by the inverter) being in itself an RCD socket.

 

6. The 13A plug has a fuse in it.

 

7. Then use the correct gauge of wire when installing it.

 

And so on.

 

I think you'll find that I myself stated "Ofc some of this can be prevented, still leads are not for permanent use."

And I think you are missing the point, some of this can be prevented yes, but people don't do they.

 

1. Yes exellent, and prefably with a designated earth bond to each powersource. ( When did you last check your GI's funtion btw, failsafe or not)

2. Fixed installations are not supposed to use flex cables if it can be avoided.

3. Cable clips are not strain reliefs.

4. Some people will have their power sources in the engine bay, so by ignorance.

5. A switch lessens the chance that people disconnects earth bounds without which the RCD will not work.

6. It might, and how about the cable to the socket.

7. That would be preffered yes.

 

The point being if you cant be arsed to fit a switch the rest of your installation is probably sub standard too.

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The point being if you cant be arsed to fit a switch the rest of your installation is probably sub standard too.

Most amateur installations that I've seen are substandard, but it's nothing to do with whether or not they have a switch. The one with the biggest and best changeover switch, for example, had no connection between earth and the hull; the wonderful switch ensured that you could safely transfer the hazard from one source to the other.

 

I also can't be arsed to fit an expensive switch, but at least I know that my own installation is not substandard.

 

 

Edited for substandard tryping.

Edited by Keeping Up
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I'm not feeling ridiculus at all as most installations without a switch probably are done by an amateur. I would probably go for the plug solution myself at an intial rebuild, but it would be my intention to replace it with a switch.

Just trying to raise the safetey awareness not trolling.

 

Apologies to the OP for this turning into a rant, I'll go start my own thread.

 

/Soren

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I'm not feeling ridiculus at all as most installations without a switch probably are done by an amateur.

You are implying that installations done by an amateur are done poorly, those done by a professional are done superbly. If only that were true, but time and time again real world experience shows that this is not true. The amateur has to live with the outcome and has the time to research and do a good job if so inclined. The professional wants to get it done as quickly as possible to get his fee and move on to the next job, knows what short cuts he can get away with, and knows that any future problems will mean more work = more money.

 

Well that too is of course a pointless generalisation so I guess that makes it 1 all!

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I'm not feeling ridiculus at all as most installations without a switch probably are done by an amateur. I would probably go for the plug solution myself at an intial rebuild, but it would be my intention to replace it with a switch.

Just trying to raise the safetey awareness not trolling.

 

Apologies to the OP for this turning into a rant, I'll go start my own thread.

 

/Soren

 

Valuable points, thank you for raising them. A professional installation has a better chance of being safe and up to standard, although that is no guarantee. Amateurs with limited electrical knowledge should err on the side of caution and pay for a proper job. Amateurs may have such knowledge but most do not.

 

And I have no problem with you ranting about safety. It might just save somebody's life.

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I'm not feeling ridiculus at all as most installations without a switch probably are done by an amateur. I would probably go for the plug solution myself at an intial rebuild, but it would be my intention to replace it with a switch.

Just trying to raise the safetey awareness not trolling.

 

Apologies to the OP for this turning into a rant, I'll go start my own thread.

 

/Soren

I used the plug and socket after it was recommended in a previous topic on here, as a safe and simple way of ensuring only one source of power could be used.

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To be clear though, you can't just do this to any inverter that doesn't appear to have it.

 

Gibbo wrote a detailed description as to how you can investigate whether an inverter is already internally earth to neutral bonded, but, more importantly, how you work out whether one can be modified if it isn't.

 

This seems to be the most relevant post.

 

Thank you for that. Sadly he doesn't say what should be done witha low frequency inverter, and I can't recall where I read that connecting neutral to earth was right for my inverter. Certainly the manual doesn't mention it.

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