# RCD, Static Caravans



## jules58

Hello All

Can any one help me out with the regulations regarding static caravans.

To cut a long story short, the meter enclosure outside had a 60amp 30ma RCD. The consumer unit in the caravan has a 60amp 30ma RCD as well, that 2 RCD's protecting the same supply. All i can remember from college is that 2 RCD's cancel each other out and cause problems.

Dont a full electrical test on the caravan, ELI, R1+R2, and RCD, everything is fine. the RCD in the enclosure outside trips out all the time, but yet the RCD in the caravan is fine. Coat, hat, boots, torch and out i go to reset the thing again.

Any info would be BOB ON!!!


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## sparkie

These would I believe class as portable buildings, as they are hard wired and not on a bs4343 blue 16 amp plug as a mobile caravan is. 

Check your regs to be sure, but you could use a time delayed rcd for the main service cutout and a regular 30 ma rcd consumer unit and earth stake for the " portable building"

this would provide discrimination for automatic disconnection of supply.

have you done an insulation resistance test on supply cables?


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## AussieApprentice

jules58 said:


> Dont a full electrical test on the caravan, ELI, R1+R2, and RCD, everything is fine. the RCD in the enclosure outside trips out all the time, but yet the RCD in the caravan is fine.


What was the minimum current required to trip the enclosure RCD when you tested it?


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## Trimix-leccy

Intermittent fault on cable from external meter box to internal?
N/E fault
Damp

Just a thought

Bite the bullet, disc. Inside unit or iso it LNE. Wait. See if o/s trips...prove that the fault is internal or external. My money is on a supply cable [meter to van fault]:thumbsup:


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## Bkessler

What percentage of domestic is on an RCD, and is nuicance tripping a problem? I have seen older washing machines and gas stoves with an igniter trip gfi's here. It seems like everything in domestic is rcd protected from reading the posts here in the uk section.


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## Trimix-leccy

Now that we have the 17th dition of the regs almost evrything domestic is on rcds. Covers all cables less than 50mm from finished surace unless within earthed metal conduit or armoured cable, all socket outlets [there are a few exceptions but not many:whistling2:]


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## Bkessler

So if the whole raceway and box is metalic no need to RCD? So is it one RCD for a consumer unit, or individual per circuit?


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## Trimix-leccy

RCD is needed if any part of cable is < 50mm from surface...difficult to achieve
Common practice now is a minimum of 2 rcds per install, this is the standard config of what is incorrectly termed a '17th edition board'. Usually supplement them with RCBOs. Every install is different and usually a pain in the a$$
Clients don't like parting with the money for an all RCBO install


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