Distribution at a Caravan Park

[SYKRAPS]

HI,

I reaslise that this subject does cause some conflicting opinions but I would like to ask a question to some more experienced guys in this matter regarding the distribution around a Caravan Park.

At the park in question I have been asked to cost for upgrades and possible extensive re-wiring due to a potential massive change in the park layout, but as of yet I have not gained access to the distribution area as it is under lock and key and some nugget has lost the key. I suspect that the park is installed wrong as TN-C-S as there is not an earth rod to be seen throughout the site (this is still to be proved).

My thoughts for the the hook ups is to wire them in groups of 4 with a double length earth rod per group of 4 at the last hook up and then to wire these back to an external distribution point which will serve 6 sets of 4 hook ups with again a double length earth rod and to devorce the DNO earth at the external distribution point so basically just TT the hook ups and the external distribution points.

My 1st question would be whether anyone can provide a link or product code for a suitable external distribution enclosure that will be pre constructed.

My 2nd question would be if you had the choice of re-wiring the positions would you use standard SWA or Split Concentric cable, I have been led to believe that with Split Concentric there is a financial saving and its easier to work (I have never used it myself). Both options would be ducted btw.

My 3rd question is would you fit a time delayed RCD unit in the origin DB or in each of the external distribution points, I am leaning towards the later so that in the event of a fault in one of the vans less people are inconvenienced.

I should perhaps also point out that 16a 30ma DP isolation will be present at each hook up for the 16a socket outlet, I have found these pre constructed for around £50 + VAT with internal metering (can anyone beat this).

Cheers Guys in advance.

 

[Engineer54]

So in the instance of the bigger static vans that are more permanent would you consider PME? I don't see how you could consider PME to be honest.

Why Not??

 

[Chr!s]

Caravan, Static, whats the difference, if both are metal framed on Wheels or Bricks insulated from the ground then ESQCR requires thet the PME not to be connected.

Bare feet, metal frame at a different potential to true earth and then the added risk of a broken PEN.

TT unless you want to break thew LAW!

 

[Engineer54]

I'm pretty sure that there is a member here, that actually lives in one of these bigger mobile homes on a residental site, that is permanently connected to the mains power supply and that the supply was PME

There is nothing bare feet on metal in these units, normally fully carpeted or laminated throughout, most of them have decking around the place too!! ...lol!!! Some of these things are massive, totally uncomparable with your typical road and holiday caravans...:smiley2:

 

[Chr!s]

I'm pretty sure that there is a member here, that actually lives in one of these bigger mobile homes on a residental site, that is permanently connected to the mains power supply and that the supply was PME

There is nothing bare feet on metal in these units, normally fully carpeted or laminated throughout, most of them have decking around the place too!! ...lol!!! Some of these things are massive, totally uncomparable with your typical road and holiday caravans...:smiley2:

Lol, i was referring to bare feet outside not inside. The op is making refernece to Hook Up's, so not a permenant Fixed Electrical Installation, these Hook Up's pose a greater risk than a fixed sytem.

I agree some Residential Park Homes may not fall into the Caravan catorgory and have Fixed PME supplys, though this would be agreed through the DNO and the Manufactureres of the Homes(Some of which state there homes are suitable for PME).

For me what the OP is describing then TT is required and falls within ESQCR.

 

[Engineer54]

For me what the OP is describing then TT is required and falls within ESQCR
​

Agree, it just that the thread somehow got sidetracked away from the OP's original questions. I had already made my comments to these, in earlier posts..

 

[MDJ]

To be fair in my ignorance ive never really read section717 as regards to static caravan's...

Suppose its up to the inspector at the time as to what regulation applys. Common sense required. Thanks for making me more aware of 717 though.

No worries fella, glad to be of help, and it is a grey area TBH, many interpretations can be assumed, as engineer points out some could be considered permanent, but not in this threads case IMO.

 

[SYKRAPS]

OK so I now have some more information about the supply characteristics as I got into the plant room today for a peep and I have some photo's of the existing installation which IMO leaves a lot to be desired.

It is a PME supply that has not been used for anything on the park as everything has been TT'd (mmmmm in a fashion) give me your opinions on what you see, there is only 1 earth rod that I can find that is at the origin (this has to be confirmed as there may be more in remote locations but not obvious) with runs of up to 100m using the SWA as the cpc that are not glanded correctly.

How do I upload photo's ?

 

[SYKRAPS]

This is the only earth rod that I could find on the site which is poorly installed at best.
This is the first in the line of 2 external distribution panels through the site that I could find
This is the only metering position that I could find at the site and the earth rod is installed behind this wall with the earth cable running up the side of the wooden back board straight from the rod to a mass joint behind the make shift enclosure above the isolation

 

[MDJ]

whats the RA reading there? under 1667 perhaps or even under 200, it well maybe that one rod serves all TT supplies haha, it looks crap but it may be the case, I still recommend converting to tt at every 4 caravan plug points, can you confirm the supply at the distribution end is tn or tt?

 

[SYKRAPS]

whats the RA reading there? under 1667 perhaps or even under 200, it well maybe that one rod serves all TT supplies haha, it looks crap but it may be the case, I still recommend converting to tt at every 4 caravan plug points, can you confirm the supply at the distribution end is tn or tt?

Distribution end has a PME connection that has not been utilised as everything is TT using the 1 earth rod that I can locate and the RA is 57 ohms

 

[MDJ]

well then providing the zs readings at the caravan sockets comply with the regs and section 7 details, not sure of what actual reg it is without looking there is no issue, seems fine to me, if you have the cable sizes worked out and rcd protection at the sockets and tt arrangments with zs readings within parameters then all fine IMO, I would prefer local earth rods myself, but hey if theres a rod and the readings are right I can't see a problem unless I'm missing something.

 

[SYKRAPS]

It appears that the SWA is used for the cpc to the external dist box and to he van hook ups, they are glanded but not earth link from banjo to an earth bar so it only takes 1 of these to come loose and if its the 1st 1 then the entire system has no earth.

 

[MDJ]

Oh dear thats not good

 

[Engineer54]

Are there any permanent buildings on this caravan park, like a social club, shop, shower/toilet block etc?? If there is then these should be connected to the PME system, not connected to that single rod.

I can't make out head or tail of that external Distribution Panel, i hope you can make a better job of it than than that!! ...lol!! Couldn't see any flying earth leads off the SWA cables, unless they are located external, in fact couldn't see Any CPC within this panel at all!!

I wouldn't rely on that single earth rod system for all of the caravan parks hook-up pitches. As suggested earlier, at least one earth rod position for each leg supplying 4 pitches, that can be linked up back to the external distribution centre's and the main intake position via the SWA armouring and/or by a third core.


Are you sure the owners are going to stump up the money for all the changes?? I agree that as it stands now, the existing installation looks to be a pig's ear, designed and installed by Muppet's!! lol!!

 

[richy3333]

Are you sure the owners are going to stump up the money for all the changes?? I agree that as it stands now, the existing installation looks to be a pig's ear, designed and installed by Muppet's!! lol!!

AKA Kermit & Miss Piggy