reversed polarity issue.

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capsco

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I am currently on my boat in France, before we left base I made up a new shorepower lead the marina we are based in has random sockets some correct polarity some incorrect, any way I have a short adapter made up to correct the errant sockets.
I have had a few weeks away from base using the new lead direct with no problems however on return to base I plugged in to a"wrong one " and my RCD tripped and would not reset until I switched the polarity, this is different to what used to happen with my old lead, things would run either way.
What should this be telling me?
 
capsco said:
I am currently on my boat in France, before we left base I made up a new shorepower lead the marina we are based in has random sockets some correct polarity some incorrect, any way I have a short adapter made up to correct the errant sockets.
I have had a few weeks away from base using the new lead direct with no problems however on return to base I plugged in to a"wrong one " and my RCD tripped and would not reset until I switched the polarity, this is different to what used to happen with my old lead, things would run either way.
What should this be telling me?
Click to expand...

it would be telling me to check the wiring of the shorepower lead connectors.
 
VicS said:
it would be telling me to check the wiring of the shorepower lead connectors.
Click to expand...

Can you expand please, I have checked the lead and can find no fault, remember it has worked faultlessly for a week on a correct polarity system.
 
Nigel likes to tease...

I always check the polarity on all the shorepower installations I use and find -in Greece - about 35% are reversed.

Unfortunately, it varies from socket to socket in many installations.

Usually no problems with those using a switch-card to credit, to which an increasing number are being converted.
 
Last edited:
capsco said:
Thanks Nigel, problem with your theory is that I will now never know!
Click to expand...
Get a mains tester plug: http://cpc.farnell.com/jsp/search/productdetail.jsp?sku=PL10052
PL1005207-40.jpg


Take it apart, and fit it in a clear 16A plug http://cpc.farnell.com/jsp/search/productdetail.jsp?sku=CN06701
42251343.jpg


Don't wire the plug to a lead, this is for testing. Not only will this tell you the polarity, it's also handy for finding the one power outlet that is actually working!

Note that these clear 16A plugs and sockets are great, as you can keep an eye on any problems. My shore power lead also has a neon on the boat end: now I know if the power has gone off.
 
Last edited:
nigelmercier said:
Get a mains tester plug: http://cpc.farnell.com/jsp/search/productdetail.jsp?sku=PL10052
PL1005207-40.jpg


Take it apart, and fit it in a clear 16A plug http://cpc.farnell.com/jsp/search/productdetail.jsp?sku=CN06701
42251343.jpg


Not only will this tell you the polarity, it's also handy for finding the one power outlet that is actually working!
Click to expand...

I already have the tester, I used the same ends on the new lead so can no longer test the old lead, before you ask the standard Blue 16 amp fitting was like new, the other end is a hubble type, so not cheap to change just for the sake of it.
 
VicS said:
it would be telling me to check the wiring of the shorepower lead connectors.
Click to expand...

capsco said:
Can you expand please, I have checked the lead and can find no fault, remember it has worked faultlessly for a week on a correct polarity system.
Click to expand...

I was thinking of incorrect connections in one or the other. Neutral and earth being swapped maybe but this would have resulted in the RCD on the supply tripping during you period of satisfactory use ... I assume the supplies were protected by RCDs in the places you visited.
 
VicS said:
I was thinking of incorrect connections in one or the other. Neutral and earth being swapped maybe but this would have resulted in the RCD on the supply tripping during you period of satisfactory use ... I assume the supplies were protected by RCDs in the places you visited.
Click to expand...


Yes Vic all installations protected by RCD???
 
I bought a testing kit for the boat and the caravan as I knew there was a problem with reversed polarity abroad. Comes with a compelte outfit of adapters etc for when the tester reveals polarity is reversed. ebay as usual!
 
Bob, yes I have the tester and the adapters, the problem is that previously the shorepower would work normally without the adapter, now it won't, I always use the adapter for safety reasons but am baffled, as to why it won't work the wrong way round now.
 
capsco said:
Bob, yes I have the tester and the adapters, the problem is that previously the shorepower would work normally without the adapter, now it won't, I always use the adapter for safety reasons but am baffled, as to why it won't work the wrong way round now.
Click to expand...

I take it that we are talking about the onboard RCD, not the supply RCD?

I also assume that your RCD stays on even when the power is disconnected and does not trip like the plug in ones.

Is there any load on the system, or appliances connected, when you plug in the shore power lead or is everything off or disconnected.
 
It sounds to me like something is connected to your shore power on the boat that wasn't previously and there is an 'earth connected to neutral' fault in it. This is tripping the RCD when polarity is reversed. If this is the case the RCD is probably saving you from a 240V shock or, worse, electrocution!

If there is anything at all connected to shore power after the RCD try disconnecting everything and then reconnecting item by item until you find the one that won't let you reset the RCD.

If everything is already disconnected (and I don't just mean switched off), including hard wired items like battery chargers, then your on board AC wiring is suspect for neutral to earth leakage.
 
VicS said:
I take it that we are talking about the onboard RCD, not the supply RCD?

I also assume that your RCD stays on even when the power is disconnected and does not trip like the plug in ones.

Is there any load on the system, or appliances connected, when you plug in the shore power lead or is everything off or disconnected.
Click to expand...

It is the onboard rcd and it does remain on.

I have tried every permutation that I can think of.

Again this issue has only arisen since I made up the new lead with the old lead either live/neutral wiring worked fine.
 
Last edited:
I don't know if it's still the case, but years ago, neutral wasn't necessarily at earth potential in France.

Trying to find a fault in a vending machine in an electronics factory, I measured 220v between L & N, 300v between L & E and 80v between N & E. I was assured by the maintenance manager that this was quite normal.
 
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