Caravan hookups

Carlosfandango · Nov 15, 2014

I was asked to test five caravan pitches for someone I've done a few jobs for. Now, I'll admit my knowledge on TT systems is not vast so I'm looking for a bit of advice. The install has been tested by a large local contractor every three years. When I got there the setup was as follows. BS 1361 cutout - meter- 63 amp 100mA rcd - 16mm Swa - 5 way db (63amp 30mA main switch) (roughly 20m away),then out to the hookups via 10 amp mcb's. There was a 10mm earth out to multiple rods connected to the RCD steel enclosure (as told by customer). There was also a 16mm earth to the PME cutout? I know this is incorrect so I disconnected it and got 110 ohms Ra. This is obviously classed as stable but not ideal. My problem is, why did this other contractor not pick up on this, or am I the one that's wrong?? Before anyone else pipes up I know there are other faults ie no overload protection on the supply to the 5 way db!
Thanks for reading!

Guest77 · Nov 17, 2014

Tourers definately every year, I haven't got the BGB with me to confirm 3 years with statics, however ,most holiday parks would have a condition report of the vans every year for insurance reasons I suspect regardless of the regs, it is cheaper insurance if the vans checked annually.

driverman · Nov 17, 2014

Jamzie said:
Statics every 3 years, tourers every year. That's what it used to be, but I've been away from the game for a few years-has it now changed?

Yes, 3 years for statics, therefore OP's site may well be a static caravan site as stated every 3 years. Depending on the actual static van tn-s is allowed, not to sure about PME though.

Guest77 · Nov 17, 2014

driverman said:
Yes, 3 years for statics, therefore OP's site may well be a static caravan site as stated every 3 years. Depending on the actual static van tn-s is allowed, not to sure about PME though.

Don't think it is an issue, TNS the better way, that said without the BGB were all guessing, Murdoch is on now, if he sees this he may put us out of our misery.

driverman · Nov 17, 2014

If residential site, TN-S can be used for direct connection to caravan. TN-C-S can also be used as long as not metal clad units. OP are the static vans metal clad? This could be why previous EICR are satisfactory.

driverman · Nov 17, 2014

[ElectriciansForums.net] Caravan hookups

Found this , hope it helps

Carlosfandango · Nov 17, 2014

It's a touring site, previous few inspections have been 3 years but I've recommended 1 year due to the findings. I've recommended a spike and individual rcbo at each hookup, doubt it if it ever gets done!!

driverman · Nov 17, 2014

Carlosfandango said:
It's a touring site, previous few inspections have been 3 years but I've recommended 1 year due to the findings. I've recommended a spike and individual rcbo at each hookup, doubt it if it ever gets done!!

Any idea why they had an EICR every 3 years? As you say touring site every year.

Carlosfandango · Nov 17, 2014

No idea, the first records show the tests were done every year, but the last two have been every 3. The company that used to do the tests have changed MD and QS so that might explain.

Engineer54 · Nov 17, 2014

So, what are your full recommendations for this sites caravan distribution system and hook-up points as stated in your Opening Post??

davesparks · Nov 18, 2014

Personally I wouldn't use isolated rods at each hookup.
I'd be looking to create one large earth nest to give the lowest most stable Ra possible, possibly installing rods at each hookup but having them all linked together.

I know it would technically be a departure but I see no issue with having an earth nest of very low Ra connected to the MET and having the PME connected.

Engineer54 · Nov 18, 2014

davesparks said:
Personally I wouldn't use isolated rods at each hookup.
I'd be looking to create one large earth nest to give the lowest most stable Ra possible, possibly installing rods at each hookup but having them all linked together.

I know it would technically be a departure but I see no issue with having an earth nest of very low Ra connected to the MET and having the PME connected.

That would be by far the best solution.

Why would you call it a departure?? All you are doing is providing an addition local N-E to the PME supply earth system. In this instance though, the Ra of the earth nest needs to be below 10 ohms, which isn't a very difficult task if you are installing a earth nest!!

davesparks · Nov 18, 2014

A departure because bs767 1 says you must not have PME connected to the caravan pitches. But with the earth nest connected I see no reason why you shouldn't have PME connected,

Carlosfandango · Nov 18, 2014

davesparks said:
Personally I wouldn't use isolated rods at each hookup.
I'd be looking to create one large earth nest to give the lowest most stable Ra possible, possibly installing rods at each hookup but having them all linked together.

I know it would technically be a departure but I see no issue with having an earth nest of very low Ra connected to the MET and having the PME connected.

That's all fair and well saying that, but it's going to be a much bigger and more expensive job to do it that way. I doubt they'll even do any of the recommendations!

Engineer54 · Nov 18, 2014

davesparks said:
A departure because bs767 1 says you must not have PME connected to the caravan pitches. But with the earth nest connected I see no reason why you shouldn't have PME connected,

Sorry, i didn't quite understand that you meant connecting the PME to the caravan. I thought you were only talking about PME up to the pitch hook-up cabinet, which is fine. Personally i wouldn't connect the PME through to the caravan, too much responsibility if something did go wrong no matter how good the TT earthing on the PME was....

Engineer54 · Nov 18, 2014

Carlosfandango said:
That's all fair and well saying that, but it's going to be a much bigger and more expensive job to do it that way. I doubt they'll even do any of the recommendations!

So what were all your recommendations for this installation then??