Caravan hook-ups, RCD's not tripping @5XIn and earthing (PME)

[Engineer54]

Looking at that main DNO cut-out arrangement, are you sure the earthing system is PME?? I can see no N-E connection at the neutral cut-out position. I think this is a TT system, and a badly designed and installed one too!!

As Chris stated, many MFTs and RCD testers will not test when the 50 volt touch threshold has been exceeded, which means your TT system needs improving. At the very least each hook-up panel will need to be roded. And as this is, (as i suspect) a TT system, the SWA of the hook-up in-out supply cables can link those rods together...

I doubt very much if your existing Rods have corroded away, not if they were from a decent manufacturer, which should have a life of around 30 years, even in mildly corrosive soils should give at least 20 years service!! Now the cable connections to these rods is another matter, they can deteriorate especially if non-standard connection methods are used. Always best to exothermic or braise weld rod connections that are not accessable by means of earth rod inspection boxes....

 

[malcolmsanford]

The earthing system is definitely PME - I've spoken to the DNO engineer that installed it

Not having seen the pictures when I OP, but agree Engineer54 they does not look like a PME head, which leads onto the very worrying part of the Richy3333 post, as above, if the DNO don't know, on what looks like a newish installation, what they have supplied, it does not bode well.

Can understand in a way a 40-50 yr old installation but I thought the DNO by the ESQCR-2002 had to keep very accurate details now.

 

[richy3333]

Thanks Malcolm & Engineer54 for your comments. The DNO was adamant that it is a PME system, however I should be going past the site today so will pop back in as the pics I took do not cover the whole set up of the equipment. More pictures to follow

'Keeping very accurate details' around here just involves the DNO engineer confirming from memory. When I rang their engineering department, they had no idea they were supposed to be able to tell me the current earthing system and ringing the DNO helpline just left me banging my head against the wall - 'computa says nooo'

 

[SPARTYKUS]

Yeah....looking back at the piccy if it's PME then there's a green and yellow cable missing

 

[Engineer54]

The Supply may very well be from a DNO PME supply, but maybe the original installation electrician didn't want the available PME connection, just the neutral, probably because he knew that PME is not permissible for caravan supplies. So it is now, from that supply origin, a totally a TT based system...

A question, are those 100mA RCDs at the origin of each sub-main S-Type?? They don't look like it to me. In fact everyone of them is of a different manufacturer, which means at least 2 of these original RCDs have failed at sometime and have been replaced.

This whole installation really needs to be thoroughly checked over, and tested, before the holiday season begins....

 

[richy3333]

Thanks everyone for your help. What a great forum
As suggested it looks as though the DNO supplied a PME intake but the sparky installing the system chose to TT the whole lot. Having had a good look, the earth is definitely not connected to the neutral. There are no service pits to suggest a ground spike etc, so god only knows where the earth runs to. And, to make matters worse the likely area for it is close to the main incoming feed cable. The current warden seems to think the installation is quite old, he suggested 40 years, but I can't see that being the case. He is trying to contact previous wardens to find out some information as the current owner inherited the site and so doesn't know much about it. Great to have a helpful client

The main RCDs are left and middle, type B and the right hand one type C? so not time delayed as the warden suggested.

I have a meeting with them next week and have suggested a full PIR, which they want completed, subject to the owner agreeing to the cost. Regrettably they are not rushed about the importance of sorting things out and are opening this weekend. The 'dollar count' is as usual, more important than the campers safety

 

[nickblake]

you cant do any more than what you have suggested what i would do is to put it all in writing , because if some thing does happen and some one is injured or worse killed then you have covered your self

 

[richy3333]

Cheers Nike. Great minds think alike. I emailed a written doc to the warden this afternoon and he has acknowledged receipt. They understand the situation, but are driven by what the owner wants to do (make money). In fact the owner seems more interested in a planning application for park lighting than resolving and earth issue. That will all change when someone is injured and the HSE descend upon them!

 

[colinnot happy]

I believe we are the campsite richy3333 is referring to here and would like to address some of his comments:
“Great to have a helpful client” I, as the manager, am doing as much as is possible in the circumstances and the new owner is keen to get everything up to spec as soon as possible. richy3333 is in full facts of the tragic circumstances behind the very recent change of ownership and sarcastic remarks such as “Great to have a helpful client” do not reflect the desire of both the manager and the new owner have to bring this site up to and above standard. I came upon this forum while searching for the equipment richy3333 has advised we purchase.
“The 'dollar count' is as usual, more important than the campers safety” - I will wager any bet that no campsite in the local area, including those owned by large organisations, is putting so much effort into getting the required checks done to the correct standard (whatever that may be). As richy3333 mentions elsewhere most things in this part of the world are done on a wink and a nod - it is not and never has been good enough for me and I am offended by the remark!
“In fact the owner seems more interested in a planning application for park lighting than resolving and earth issue. That will all change when someone is injured and the HSE descend upon them!” There is, and never has been, any planning application for park lighting. This was something discussed by the previous owner and was dropped in favour of getting the correct checks done and any improvements made long before the start of the season. I have read the 9 page report provided by richy3333 and can find nowhere anything which he classes as dangerous and in need of urgent attention and we have acted upon any recommendations.
In summary: a “qualified electrician” installed all the systems on this site to the regulations current at the time of installation with the exception of covering one row of cables with protective concrete plinths - which I have discussed with richy3333 and the matter is in hand to be rectified as soon as is possible.
As manager I have in the past engaged what I have been led to believe were and are qualified electricians - they advertise as such in local papers and if they are not qualified I would have expected them to have been found out by now. If richyy3333 knows or suspects these people are not qualified I suggest he reports them to the HSE as it is they not we who are endangering the public! As manager I doubted their work and have now engaged richy3333 - if I have engaged another duff electrician would the good members of this forum please let me know and tell me where I can find one who knows the regulations backwards? I cannot see how I or the family who own this park could do more.
If I have learned anything in the last 4 years - and from reading this forum I am convinced of it - is that if I asked 6 electricians a question I would get six different answers! This is why I engaged yet another “qualified electrician” to take over the checking of the site.

 

[Farmelectrics]

sorry chaps brain freeze whats dno please explain

 

[Sintra]

Distribution network operator or in other words the electricity supplier.

 

[ukpablo]

distribution network operator ( supplier)

 

[tony mc]

Leccy Board

Distrobusion Network Operator