Working underneath the van I had a shock when I touched the chassis.So it occured to me that although the earth goes to the chassis it does not go to ground unless the corner steadies are down as it sits on rubber. And it further occured to me that it still will not go to ground as I use plastic corner steady pads or blocks of dry wood as most people do. So why are the vans not provided with old fashioned earth straps? I think a short lenghth of cable with a croccodile clip on one end and a steel camping peg on the other is on the way. The jolt recieved felt like static electricity but it could have been 240V. You have to provide an earthing rod at home even though you have a earthleakage trip.?????
Bit of a shock
- Thread starter hughdavies
- Start date
Hi Hugh,
Your post got me thinking.
I connected one lead from my multimeter to the earth pin on the 240V mains inlet socket and then checked for continuity against the chassis. As I suspected the caravan chassis is connected to the earth wire on the 240v hook up socket. Even the side panels are because I got close to zero resistance when touching the awning rail with the other lead.
Of course, it will all then depend on the quality of the earthing at the hook up bollard, so your idea of a ground spike could make sense as a belt & braces approach.
Your post got me thinking.
I connected one lead from my multimeter to the earth pin on the 240V mains inlet socket and then checked for continuity against the chassis. As I suspected the caravan chassis is connected to the earth wire on the 240v hook up socket. Even the side panels are because I got close to zero resistance when touching the awning rail with the other lead.
Of course, it will all then depend on the quality of the earthing at the hook up bollard, so your idea of a ground spike could make sense as a belt & braces approach.
Putting down an earth spike will not eleviate the problem.The chassis of the van should be earth bonded to the 240 volt inlet.It could be that the earth connection on the feed cable has a poor contact or has come out of the plug/socket.If you received a shock from the van there is a fault that needs looking at.
Whatever you do DO NOT connect your caravan chassis to ground. The nearest earthing point of the supply system may be at a substation some distance away which could mean that you earth is better than that of the supply company and considerable current could flow albeit from a very low voltage.
With a functioning RCD fitted to the caravan, the earth connection to the bollard would have to be very poor quality indeed to cause a safety issue. if your shoch was an instantaneous jolt that did not trip the RCD, then chances are that it was static jumping from you to the well earthed caravan rather than the other way around. If your shock was a continuous tingle, then something is astray and you should have an electrician check it out.
There is an earthing point on the chassis, with a do not remove sign. So with the legs down bare on the soil the van earth does go to groud by design. The point I am making is we are blocking of this earth by using plastic and wood as insulators.
hugh
the shock you felt through the van chasis was undoubtedly a static discharge similar to the shock you sometimes get from the car door handle in hot weather, yet the car sits on 4 rubber tyres with no viable earth. think of it this way the 240v system is earthed through the chasis and into the national grid via the hookup cable and bollard but the 12v system which is also earthed to the chasis and the car via the white return wire does not blow up when the hookup is connected does it???
this is because there is no residual or current power in the earth of the 240v system, unless there is a short on one of the components that is what the MCB's are for as well as protecting the rest of the system in the event of a overload.
at no time is there any current in the earth of 240v system "unless there is a fault" otherwise it would blow all the 12v system when the hookup was connected, remember electric current allways goes via the shortest route whatever that is.
the shock you felt through the van chasis was undoubtedly a static discharge similar to the shock you sometimes get from the car door handle in hot weather, yet the car sits on 4 rubber tyres with no viable earth. think of it this way the 240v system is earthed through the chasis and into the national grid via the hookup cable and bollard but the 12v system which is also earthed to the chasis and the car via the white return wire does not blow up when the hookup is connected does it???
this is because there is no residual or current power in the earth of the 240v system, unless there is a short on one of the components that is what the MCB's are for as well as protecting the rest of the system in the event of a overload.
at no time is there any current in the earth of 240v system "unless there is a fault" otherwise it would blow all the 12v system when the hookup was connected, remember electric current allways goes via the shortest route whatever that is.
Hi Hugh
i had the same problem last year with my ABI and discoverd the problem was my lead after changing this i no longer had the problem
i had the same problem last year with my ABI and discoverd the problem was my lead after changing this i no longer had the problem
It is essential that you have the caravan connected to earth via the hook-up cable and if you wish to add an extra earth via an earth rod then that is ok as well, but really not req'd.
The easiest way to check that all is well by using a plug-in mains tester, this will check the polarity and indicate if you have an earth connection.
If your caravan is not connected to earth, then a condition could arise if you have an electrical earth fault e.g. faulty kettle, then the chassis could be live and if you grounded yourself by perhaps exiting the van and touching the earth whilst also touching the van then you stand a good chance of electrocution, although the van RCD should trip, why take the chance?
Ebay have them for
The easiest way to check that all is well by using a plug-in mains tester, this will check the polarity and indicate if you have an earth connection.
If your caravan is not connected to earth, then a condition could arise if you have an electrical earth fault e.g. faulty kettle, then the chassis could be live and if you grounded yourself by perhaps exiting the van and touching the earth whilst also touching the van then you stand a good chance of electrocution, although the van RCD should trip, why take the chance?
Ebay have them for
Hello colin,
Just a technicality, The chassis of a caravan should be bonded to the CPC (Continuous Protective Conductor) commonly know as the earth. The chassis should not be considered as a replacement or alternative for the CPC in any part of the system. Its small but important difference. the way your reply reads makes it sound as though the chassis is used to complete the CPC throughout the caravan.
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