Caravan hookups

[Engineer54]

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]

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]

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]

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]

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??

 

[Carlosfandango]

I wondered how long it would take before it turns into a witch hunt!

 

[Engineer54]

I wondered how long it would take before it turns into a witch hunt!

Eh, what ''Witch Hunt' are you on about then??

 

[Carlosfandango]

Well it seems to me that your asking for my recommendations then probably criticise each one. Maybe I'm wrong but thats how i see this going!

 

[Engineer54]

I was asking, to see if you had picked up on all the relevant deficiencies of the original installation.

These caravan sites are publicly used areas and therefore need to be safe. If you are putting your name to a bit of paper that is stating that it is safe, or will be safe if your recommendations are acted upon. The last thing you want, is to be the scapegoat that everyone points the finger at for all or most of the blame if something does go wrong!!


But if you're satisfied with your reporting on this caravan installation fine issue the paperwork and move on to your next job!!

 

[Carlosfandango]

I apologise, I'll put them up tonight.

 

[Carlosfandango]

I thought I was gearing up for a public slagging. Maybe still am when I post them! Ha

 

[Engineer54]

I thought I was gearing up for a public slagging. Maybe still am when I post them! Ha

May be, but at least if there is any slagging, the slagging won't be in a magistrates court or worse!! lol!!

 

[driverman]

I don't carry out EICR's, but if the OP has carried an EICR and recommended XYZ etc and handed it to the customer, that's the OP's job done isn't it?
Is it not up to the customer if they want the work doing or not and who by? In this particular case though to obtain a satisfactory report to obtain a license to operate the site C1 + C2 will have to be attended to. In theory anyhow.

 

[ImpededLoop]

I don't carry out EICR's, but if the OP has carried an EICR and recommended XYZ etc and handed it to the customer, that's the OP's job done isn't it?
Is it not up to the customer if they want the work doing or not and who by? In this particular case though to obtain a satisfactory report to obtain a license to operate the site C1 + C2 will have to be attended to. In theory anyhow.

The decision is up to the owner as to whether they take the advice of the test engineer.

The OP is just checking that his thoughts are correct about the earthing arrangements and one or two other possible deviations. He's followed on from a large company who have been testing the site and understandably wants to check his thoughts are correct before handing them to the person ordering the work. It's possible that this person may then question his recommendations as the previous company never highlighted them.

 

[davesparks]

Who said anything about an engineer? You only need to be an experienced electrician to carry out EICRs

 

[ImpededLoop]

Quite true Dave. My personal opinion though is that an experienced and highly skilled electrician is an engineer. However I'm happy to agree to differ and not take a good thread off on a tangent.

 

[Guest77]

I wondered how long it would take before it turns into a witch hunt!

Why would you think that, you posted up a lot of information and are asking fellow sparks for their opinions, nothing wrong with your posts here mate.

 

[Guest77]

Well it seems to me that your asking for my recommendations then probably criticise each one. Maybe I'm wrong but thats how i see this going!

No we may well agree with most of your recommendations then suggest some others or point out one or two may be wrong, no witch hunt here in this thread, well yet :biggrin:

 

[Engineer54]

Quite true Dave. My personal opinion though is that an experienced and highly skilled electrician is an engineer. However I'm happy to agree to differ and not take a good thread off on a tangent.

And how does a highly skilled electrician get elevated to Engineer status?? Technician is the recognised title for a highly skilled tradesman, that sadly rarely gets used these days...

 

[davesparks]

Quite true Dave. My personal opinion though is that an experienced and highly skilled electrician is an engineer. However I'm happy to agree to differ and not take a good thread off on a tangent.

Who is and is not an engineer is well defined.

For a start a degree in engineering is required

 

[ImpededLoop]

Fair enough. I stand corrected!

 

[happysteve]

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.

A departure from a statutory regulation? You're a braver man than I am...:angel_smile:

 

[davesparks]

Statutory regulation?

 

[happysteve]

The Electricity Safety, Quality and Continuity Regulations 2002. Part II, 9. (4).

 

[Carlosfandango]

Recommendations I've suggested are,
1. Fit 63amp mcb in 100mA rcd enclosure to protect 16mm cable. (currently protected by dno 100amp fuse)
2. Disconnect existing earth rod at supply end and pme supply cable to outside dist. board.
3. Replace 30mA rcd at dist board and fit main switch, replace 10 amp with 32amp mcb's that supply hookup sockets (currently there is a 6mm 3core that supplies 2 x sockets, 2 live cores sharing a neutral)
4. Fit new hookup enclosures containing 2 x10 amp 30 mA rcbo and 2 x 16 amp socket outlets ( caravan club apparently recommend 10a mcb?)
5. Isolate pme supply at hookup and install earth rod at each one.
What's your thoughts? I know it's not ideal but short of ripping it all out and starting again, which isn't gonna happen!!

 

[davesparks]

The Electricity Safety, Quality and Continuity Regulations 2002. Part II, 9. (4).

Which says:
(4) The distributor shall not connect his combined neutral and protective conductor to any metalwork in a caravan or boat.

I am not a distributor and I would not be connecting a CNE conductor to anything.

Exactly how would I have made a deviation from this ???

 

[Guest111]

For what it's worth I used to do a lot of camping and every site I've been on has had one earth rod per hook up point,also best practice is to use an individual mcb/rcd per outlet as there is always some numpty who'll try and use 2 heaters and a kettle and trip the breaker.

 

[Engineer54]

[

Recommendations I've suggested are,
1. Fit 63amp mcb in 100mA rcd enclosure to protect 16mm cable. (currently protected by dno 100amp fuse)
Make that an S type 100 or 300mA RCD......

2. Disconnect existing earth rod at supply end and pme supply cable to outside dist. board.
I wouldn't bother disconnecting the earth rod connection, leave it in....

3. Replace 30mA rcd at dist board and fit main switch, replace 10 amp with 32amp mcb's that supply hookup sockets (currently there is a 6mm 3core that supplies 2 x sockets, 2 live cores sharing a neutral)
Not sure what you mean by (2 live cores sharing a neutral)??

4. Fit new hookup enclosures containing 2 x10 amp 30 mA rcbo and 2 x 16 amp socket outlets ( caravan club apparently recommend 10a mcb?)
Fine, so long as the RCBO's are DP not SP!!

5. Isolate pme supply at hookup and install earth rod at each one.
Fine, remember the hook up cabinet can be PME, it is the supply to the caravan that needs to be isolated and on a TT earth... The hook-up cabinets i've seen for caravan pitches have two small earth bars, one for the incoming earth (pme) and one for the TT earth.

What's your thoughts? I know it's not ideal but short of ripping it all out and starting again, which isn't gonna happen!!

What do you mean by '(currently there is a 6mm 3core that supplies 2 x sockets, 2 live cores sharing a neutral)'' ?? 2 line cores run in parallel from existing 10A MCB in 5 way DB, or 2 line conductors supplied from 2 separate MCB's in the 5 way DB??

BTW how many caravan pitches are there on this caravan touring site?? And what other buildings are being provided for, like club house, shop(s), shower rooms etc??

 

[Carlosfandango]

There's 5 pitches, no other buildings at all. Very small site. Two lives fed from two mcbs. I know shared neutrals is a no no but my reckoning, right or wrong, was that as it's 6mm cable and fed by 10 amp then the neutral will be capable of carrying the load?

 

[Engineer54]

There's 5 pitches, no other buildings at all. Very small site. Two lives fed from two mcbs. I know shared neutrals is a no no but my reckoning, right or wrong, was that as it's 6mm cable and fed by 10 amp then the neutral will be capable of carrying the load?

Surely if all 5 ways of this 5 way DB are being used that would, be 10 caravan pitches and 5 hook-up cabinets?? Or are you saying only 3 of these MCB's are being presently used??

Makes you wonder how anyone can get such a small installation wrong, It would have cost almost the same amount of money initially to do things right in the first place!!

 

[happysteve]

Which says:
(4) The distributor shall not connect his combined neutral and protective conductor to any metalwork in a caravan or boat.

I am not a distributor and I would not be connecting a CNE conductor to anything.

Exactly how would I have made a deviation from this ???

From the ESQCR 2002, Explanatory Notes ("This is not part of the Regulations"):

Regulation 9 contains requirements for distributors operating protective multiple earthing systems, including the circumstances in which earthing terminals of consumers' installations should not be connected to the distributor’s combined neutral and protective conductor.
​

Also BS7671 (non-statutory) cites the ESQCR 2002 in 708.411.4:

The ... ESQCR 2002 prohibit the connection of a PME earthing facility to any metalwork in a leisure accommodation vehicle (including a caravan).
​

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.

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,

It's not BS7671 you'd be making a departure from, it's the ESQCR 2002.

As for "I am not a distributor," if you believe that this means that the statutory regulation does not apply to you then I will stand by my earlier statement about you being a braver man than I am...

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....

... and braver than Engineer54 as well by the sounds of it. You must have stones the size of melons.

 

[Carlosfandango]

Surely if all 5 ways of this 5 way DB are being used that would, be 10 caravan pitches and 5 hook-up cabinets?? Or are you saying only 3 of these MCB's are being presently used??

Makes you wonder how anyone can get such a small installation wrong, It would have cost almost the same amount of money initially to do things right in the first place!!

There are 2 posts each with 2 hookups on each, fed by 1 x 6mm 3 core to each, then 1 hookup on the outdoor db itself, making 5 hookups. To the remote hookups red is one live, yellow another, blue a shared neutral and the armour serving as an earth. Hope that makes sense?

 

[Engineer54]

Yes that makes sense, not the most intelligent way of doings things mind!! lol!!

 

[Richo77]

What about if it was a tn-s Earth system. Would you still have to disconnect the tn-s Earth and then use a TT system on the commando socket to the touring caravan? I think you would still have to use a TT but not sure.

 

[Jamzie]

No Richie. TN-S is permitted

 

[7029 dave]

The cutout fuse will act as the OCPD for the 5 way board depending on how the SWA is run so there is no chance of it being damaged etc although the DNO may not like it. What size is the main bullet?

The sole purpose of the cut out fuse is to protect DNO equipment , cable etc.