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Quote: Originally posted by jonnie45 on 18/8/2012

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Quote: Originally posted by evenstephen on 18/8/2012Forgive me for asking but was the gentleman concerned British? I only ask because I've never seen anyone on British sites use such an arrangement in all my years of camping. We all use the proper EHU cable. And on my one tour of Denmark all the sites had exactly the same sort of site outlet to plug into that we use in Britain so there was no need to use any sort of connector. So whilst it's probably all good advice I'm a bit baffled.

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Hi

I think the primary reasons are....

To save money - perhaps a B&Q lead is cheaper than a proper camping lead.

Flexibility

It may be as simple as thats what they have to hand.

QUOTE: We all use the proper EHU cable.

I have heard UK campers before claim that they ALL use the correct gear - is it really true?

I suspect what may be going on here is more along the lines that if you ask a person whether there have been many house fires in his town recently he may recall that he has not seen any and say none - if you ask a fireman you may get a different answer!

Hope I am not being rude in the above but we get Danes and Germans with inappropriate leads or configurations and these are socities which are pretty hot on rules and standards, I just find it a bit odd that all British campers would be otherwise.

Jon

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Quote: Originally posted by saxo1 on 18/8/2012

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The problem with trying to discriminate purely using trip current ratings is if the leakage current of the downstream RCD is in excess of it's rating then the upstream RCD will detect the same leakage current. i.e. if the leakage were 100 mA then a 10 mA and a 30 mA RCD will both detect the leakage and both will trip.

Saxo1

 

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I can only speak for the specifications in the U.K. but I suspect that the majority of RCDs are manufactured to the same tolerances.

The UK requirements for RCDs is that they should operate between 50% and 100% of their rated tripping current,most 30 mA RCDs operate at between 18 mA and 23 mA.You will see that if a 10 mA RCD is manufactured to the same standard its tripping current could possibly be as low as 5 mA,I think this would be far too low for the harsh conditions experienced on a campsite and would lead to nuisance tripping.A 30 mA RCD is considered to be the safest and least troublesome for personal protection.

To ensure discrimination a factor of three is required for the upstream RCD so a 30 mA RCD would need a 90mA RCD(a 100mA unit is normally used) upstream and it would also need to be a type C time delayed.It doesn't have to be  time delayed  but if you want to guarantee discrimination it needs to be.

If all your pitches have individual 30 mA RCDs then under the regs in the UK a 100mA time delayed unit is acceptable upstream,this then copes with the discrimination problem and also the combined earth leakage situation caused by capacitance and imperfect insulation from the total no of units connected.

As all the downstream RCDs offer the required personal protection then the function of the upstream RCD is mainly equipment protection, fire prevention being the primary one, but it will still offer a reduced level of shock protection.

The above applies to the UK it may be different for mainland Europe

Saxo1

Quote: Originally posted by saxo1 on 19/8/2012

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I can only speak for the specifications in the U.K. but I suspect that the majority of RCDs are manufactured to the same tolerances.

The UK requirements for RCDs is that they should operate between 50% and 100% of their rated tripping current,most 30 mA RCDs operate at between 18 mA and 23 mA.You will see that if a 10 mA RCD is manufactured to the same standard its tripping current could possibly be as low as 5 mA,I think this would be far too low for the harsh conditions experienced on a campsite and would lead to nuisance tripping.A 30 mA RCD is considered to be the safest and least troublesome for personal protection.

To ensure discrimination a factor of three is required for the upstream RCD so a 30 mA RCD would need a 90mA RCD(a 100mA unit is normally used) upstream and it would also need to be a type C time delayed.It doesn't have to be  time delayed  but if you want to guarantee discrimination it needs to be.

If all your pitches have individual 30 mA RCDs then under the regs in the UK a 100mA time delayed unit is acceptable upstream,this then copes with the discrimination problem and also the combined earth leakage situation caused by capacitance and imperfect insulation from the total no of units connected.

As all the downstream RCDs offer the required personal protection then the function of the upstream RCD is mainly equipment protection, fire prevention being the primary one, but it will still offer a reduced level of shock protection.

The above applies to the UK it may be different for mainland Europe

Saxo1

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Quote: Originally posted by millermicm on 18/8/2012

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And Always unwind the cable fully to avoid heat building up on the reel and melting the plastic covering.

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Quote: Originally posted by mjnewton on 20/8/2012Hi Jon,Just read through your thread and was wondering what the intended purpose of the central (feeding 20 points) 30mA RCD was?

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Given that each socket is individually protected by its own RCD (as required by the latest regs) the upstream 30mA RCD serves no real purpose and is indeed likely to suffer from nuisance trips given the lack of discrimination as discussed.

The wiring between your central distribution point and each pitch outlet should be installed and physically protected (depth or height below/above ground, mechanical protection, etc) such that no additional protection is required to guard against electrocution. As Saxo suggests, a time-delayed 100mA (possibly even higher as that is only 5mA leakage per pitch) would be your best belt-and-braces option in the distribution point. Overcurrent protection is still required to protect the wiring to each outlet but that is a separate issue.

It should be borne in mind that so-called nuisance trips could themselves be a safety hazard should an unsuspecting camper be plunged into darkness as a result of the action of another camper e.g. from trips/falls, scalding, etc and so mitigation of this risk should have been designed in at the outset. It is on this basis that, for redential properties, 'whole-house' RCDs are no longer permitted by the regs because more people were being killed/injured from falls down stairways in the dark than would otherwise be caused by fixed wiring faults that the RCD was intended to protect!

Hopefully this goes without saying but you should seek the advice of a qualified electrician rather than taking anything said here as necessarily valid. Aside from anything there are many other factors, such as the type of supply and distribution earthing, that will also have an influence over exactly what protection is required.

Mathew

Post last edited on 20/08/2012 23:25:15

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Quote: Originally posted by evenstephen on 18/8/2012

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Forgive me for asking but was the gentleman concerned British? I only ask because I've never seen anyone on British sites use such an arrangement in all my years of camping. We all use the proper EHU cable. And on my one tour of Denmark all the sites had exactly the same sort of site outlet to plug into that we use in Britain so there was no need to use any sort of connector. So whilst it's probably all good advice I'm a bit baffled.

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Quote: Originally posted by jonnie45 on 21/8/2012

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I assure you that standards/regs that determine what I can or cannot do in Denmark are very high and anything I do is subject to regular inspection.

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Quote: As far as I understand it the RCD at the pitch may not protect the operator digging or working upstream.

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