Safety Issue - connecting to mains at home?
Comments
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Well that seems to have cracked it! Just did a retest and it is showing 2v from the caravan chassis to an electrode poked into the ground.
Thank you everyone for your input. I don't think I would have been injured by the voltage on the caravan but it clearly needed investigating. The disconnected earth wire served the sockets in the garage as well so identifying the problem and fixing it may
have saved me from a serious shock from any faulty equipment plugged in.It is though worrying that having done what I think was the correct thing .... i.e. fitting a RCB to the caravan supply ... the device did not indicate there was a problem. And electrical testing is not normally done in a house except when major changes
are made. I would not expect to have to get a check done just because a workman had replaced a garage door motor and wired it in to an existing connection...0 -
Yes put as pointed out a caravan site, construction site, and i believe a Fuel station, should not be supplied by a PME supply?
So its not really recommended to supply a caravan at home thats fed from PME.?
I don't fully understand why, but thats the regs.
The OP could have located his problem pretty quickly if he had followed an early suggestion, which suggested a plug in tester?
I have one of these, and they do work for locating lost earths.
[url=http://www.toolstation.com/shop/p82826?table=no] TESTER[/url]
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There was indeed a mention of checking the polarity in an earlier post - which I did, but I failed to even consider that the socket might not have been earthed properly and xtrailman's suggestion of using a gadget of the type shown is an excellent one. Maybe
this should be part of the guidance issued by the club - to test the socket you are going to connect the caravan to? I am ordering one of these immediately.I also feel that the substantive question as to whether a caravan should be connected to a PME supply is still an open one and have raised that in a question to the Caravan Club specialists. I will post their reply in here when it comes.
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Glad you found the solution but, as you say, there is still the unanswered question about PME. You would think that the caravan is connected into the equipotential bonding system of the house and should not be an issue but it is worth checking.
I have learned a lesson here - making assumptions about your electrical system being properly earthed and jumping in with the advanced discussions on neutral voltages and "true earth".
Thanks for posting and please post again if you get an answer to the PME issue.
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Still no answer from the Caravan Club experts so I am going to send a reminder....
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I got a response from the Caravan Club as below. I think it is a bit of a cop-out but the last paragraph confirms that a separate earth is 'best practice'. I hope this discussion has been helpful to others as well as resolving my own problem.
Thank you for your email.
This was an issue raised in 2012 after an article in a publication about caravans using domestic power, please see attached report.
However, following discussion with the industry’s trade association, the National Caravan Council, it is suggested that caravan owners should not be unduly alarmed by the article from the issue of ‘Switched
On’, the trade magazine of The Electrical Safety Council. Technically, the article is correct, however a practical view of the situation would suggest that most owners:a) Would not know what earthing system their house has, nor understand in sufficient detail the significance of the different earthing options – there is a real risk of a concerned owner doing more
harm than good by attempting to ‘improve’ their electrical installation without sufficient knowledgeb) Would not be vulnerable to some fault conditions anyway, as the protective circuitry in the house should offer safeguard against some common faults – i.e. the ‘common practice’ method of connecting a caravan to the house supply does not leave
people unprotected, but rather not protected as thoroughly as would be desirablec) Would only be vulnerable to an appreciable risk of harm as described in the article if a specific combination of faults were to occur – while such faults are undoubtedly possible, they are not commonplace, especially if the condition of the
caravan, hook-up lead and house supply is good and well-maintainedFor ultimate safety, owners should seek the advice of a qualified professional electrician to assess the design and condition of the electrical installation in their house, and to make specific recommendations
regarding safe connection of a caravan to it. The use of an externally-positioned mains connection socket supplied via an RCD and connected to a separate earth point represents best practice, and would be encouraged. Owners should not be tempted to install
such a connection themselves, however, unless definitely competent to do so. In particular, the installation of an earth connection of proven effectiveness requires a degree of knowledge and usage of test equipment which is beyond the familiarity of most DIY
enthusiasts, for instance.I hope this helps.
Regards
Kelly Henderson
Technical Advisor
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Brian I would have cut out the middle man and put your letter straight in the shredder.
I suspect a TT system is preferred on a campsite as the caravans are likely to be quite a way form the main earth point and outside the main equipotential zone , so if a spike is fitted close to the caravan then the caravan metal work will be tied down
to the same potential as the earth around it.0 -
I think this is a good response from the Club. Nothing can be 100% safe under every situation, in particular when there are multiple faults, so it is a pragmatic reply.
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