Can somebdy please tell me what happens if you plug a normally wired EHU into a reverse polarity hookup?...I presume lighting will still work or does the RCD not allow the reversed polarity and thus not allow any power to flow??
The rcd with probably still work also all your appliances, but the problem arises where the neutral conductor becomes the live and the live becomes the neutral and hence your equipment will not be protected by their fuses and there will be a permanent live to each appliance which cannot be switched.
IT WILL BE EXTREMLEY UNSAFE TO USE SUCH A SUPPLY
I think I would be correct in saying that this only seems to occur abroad when european sites who still use the "Stuko" type plug, this is a two pin plug into their supply.
Using the normal BS4343 commando style plugs (Blue 3 pin) one would not normally expect to come across a reverse polarity, although you can never be to sure and I also use a plug tester (cheap enough to buy) to determine that the supply has been correctly wired. I even use it in UK!!! just to be safe.
Cheers Andy...I thought that maybe the case...have packed my electical (neon)screwdriver so will check hookup polarity with this..will flip wires in EHU if required.
That is another way of doing it but was not sure of your electrical experience so appologies if I was teaching you to "suck eggs", from your reply I'm sure you know what you are doing.
Although I had to do a little research on the RCD as I dont think some makes would work as it would depend on where the sensor was placed within the RCD, but I think most would.
Thanks Andy...I asked the question because it seemed that there were plenty of posts about campsites with reverse polarity and how to combat it but nothing seemed to mention what happens if you plug in and use it without checking.
No need to appologise regarding 'egg sucking'...am pretty 'au fait' with electrics but it's good to get other peoples knowledge and experiences sometimes.
Off to sunny France on Saturday for 2 weeks so hopefully I'll be lucky with the hookups.
The RCD will still work correctly, and the overcurrent MCB will still trip when required. However the MCB will not disconnect the live conductor nor will the switch on most appliances. I would describe it as highly undesirable rather than highly dangerous, but well worth checking before connecting.
Quote: Originally posted by Peridot on 08/6/2006 The RCD will still work correctly, and the overcurrent MCB will still trip when required. However the MCB will not disconnect the live conductor nor will the switch on most appliances. I would describe it as highly undesirable rather than highly dangerous, but well worth checking before connecting.
I would still suggest that it is extremely unsafe rather than undesirable for the reason that you mentioned, the MCB will not disconnect the live conductor, which if the supply is isolated on the breaker one would assume that the live conductor was disconnected from supply, a voltage test on the live would show this (most people would use the electricians 240v insulated screwdriver) which tests live against the potential of earth. Not many would have the facility, nor think it necessary, to test the potential of Live and Neutral (or even neutral and earth). Hence the neutral would still be live with the supply supposedly isolated, lets just hope the RCD trips out at 30mA and 0.4 seconds!!!! (a periodic appliance test would determine this)
The only way to ensure complete isolation is to use two-pole breakers which would not normally be necessary providing the installation is correct
The socket tester costs £3.99 a small price to pay to check if the system is safe. The only thing the socket tester would not checked is a neutral/earth reversal, which would just be down to a poor installation but would be identified during periodic testing.
This post has not been made to scare anyone but just to emphasize the importance of having a correct EHU which has been discussed in loads of other posts.
This is why I regularly look at this website. This is good information.
We spent last week camping in France with EHU. Even though everything worked, we could have had a problem, and all of our equipment would have remained live.
I knew about reversed polarity before today but it has taken this post for it to sink in.
Thanks to all.
------------- Some days I am the statue - others the pigeon.
The socket tester costs £3.99 a small price to pay to check if the system is safe. The only thing the socket tester would not checked is a neutral/earth reversal, which would just be down to a poor installation but would be identified during periodic testing.
This post has not been made to scare anyone but just to emphasize the importance of having a correct EHU which has been discussed in loads of other posts.
Andy
Excellent and unarguable advice
It's worth emphasising that the MCB/RCD are not intended to be used as isolating switches and that all parts of the installation should be treated as potentially live unless the EHU plug is completely removed from the site socket.
I've built the socket tester circuit into my EHU to give a constant indication of the supply integrity.
It's worth emphasising that the MCB are not intended to be used as isolating switches
This point is debateable but this is certainly not the place, as long as end users are aware of the dangers of electricity, as Im sure most people are, and use the correct rated/IP protected proprietry equipment discussed in other posts and also be aware that a reversal of the polarity of a few sites does occur.
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Topic: Ehu and reverse polarity?
