Caravan diversity question

[Pretty Mouth]

What allowance for diversity, if any, would you apply to caravan hookup sockets?

The circuit will have just one hookup point, with two 16A sockets. It's a fair distance from the CU, so voltage drop is going to be significant. It would be good to keep the cable CSA down if feasible.

 

[brianmoooore]

I've provided Pretty Mouth with my opinions on the maximum design load and provided some info on the layout of sites. Armed with this, and opinions from any others who have contributed, I'm quite sure that he is quite capable the cable size and its protection requirements, so I wouldn't presume to advise on whether an upfront S type RCD is required or not.

 

[Pretty Mouth]

Guys, a big thank you for all your help with this, you've all been a great help

 

[UNG]

I understand that one isn't required, but my reasoning for using one would be mainly for a damaged hook up point where the live conductor could come into contact with the TT earth.

Imo if it was a fixed CU and met disconnection times etc then I would have no problem, but these hook-ups are usually just a stake in the ground and there's always going to be the risk of driving off without unplugging.

I suppose a lot depends on what facts you base your risk assessment on
We often talk about best practice on here and best practice before pulling away from a pitch or even after a rest stop is for the driver to do a walk around check to ensure that the vehicle and trailer are good to go before getting into the driving seat.
It could also be argued that someone may damage a hookup point reversing onto a pitch but I don't know any owners who would risk damaging their van in that way and would assess how they were going to place the van before reversing and even have someone watching them back
I would say the risk of either happening is so minimal it is not worth considering

 

[mainline]

I suppose a lot depends on what facts you base your risk assessment on
We often talk about best practice on here and best practice before pulling away from a pitch or even after a rest stop is for the driver to do a walk around check to ensure that the vehicle and trailer are good to go before getting into the driving seat.
It could also be argued that someone may damage a hookup point reversing onto a pitch but I don't know any owners who would risk damaging their van in that way and would assess how they were going to place the van before reversing and even have someone watching them back
I would say the risk of either happening is so minimal it is not worth considering

https://www.rvtravel.com/yikes-rver-forgot-unplug-electric-cord-drove-1009/

n.

I wouldn't like to be the one saying to the mother of an electrocuted child, we could maybe have saved her, but it wasn't even worth considering.
Like the Titanic.
They also make alarms to warn you if still hooked up, so I guess someone thinks there's a market for them.
IMO for the price of an S type RCD it would be a no-brainer in adding one.



Funny enough, I went and stayed on a campsite a few weeks ago in a motorhome for the first time and my hookup cable was too short, so it ended up being like a washing line.
The following morning we went to a car park in BlackRock bay, but couldn't get in as someone with a trailing axle motor home had reversed over a post which was in the middle of opening gates the back end of his camper was a mess after a tractor pulled it off the post.

I would rather exemplify best practice rather than talk about it

 

[UNG]

https://www.rvtravel.com/yikes-rver-forgot-unplug-electric-cord-drove-1009/

n.

Why use an American site to make your point,

I wouldn't like to be the one saying to the mother of an electrocuted child, we could maybe have saved her, but it wasn't even worth considering.
Like the Titanic.
They also make alarms to warn you if still hooked up, so I guess someone thinks there's a market for them.
IMO for the price of an S type RCD it would be a no-brainer in adding one.

There is an enormous faith placed on RCD's maybe it would be a no brainer to install two RCD's in series so if one fails the other might operate, all too often I find RCD's that operate outside of their specified ratings so how do you explain to someone that the safety device that was meant to protect them failed

Funny enough, I went and stayed on a campsite a few weeks ago in a motorhome for the first time and my hookup cable was too short, so it ended up being like a washing line.

So we have poor design of the site and placing of the hookup's or a short hookup lead

The following morning we went to a car park in BlackRock bay, but couldn't get in as someone with a trailing axle motor home had reversed over a post which was in the middle of opening gates the back end of his camper was a mess after a tractor pulled it off the post.

In 40 years of camping and caravaning I have never seen it happen or seen the aftermath of it happening

I would rather exemplify best practice rather than talk about it

Best practice is often talked about and rarely agreed on

 

[pc1966]

There is an enormous faith placed on RCD's maybe it would be a no brainer to install two RCD's in series so if one fails the other might operate, all too often I find RCD's that operate outside of their specified ratings so how do you explain to someone that the safety device that was meant to protect them failed

I personally prefer to have ADS based on the OCPD whenever practical and keep the RCD for "additional protection".

What seems to be lacking in most cases is any on-going testing of them. In spite of the test button. And stickers. And supplied documents.

Don't caravans already have a 30mA RCD inside as well?

No idea as I rarely set foot in caravans, but would caravan users typically test the RCD on the power outlet when first connecting up? Is that in any guidance/best-practice that folks get for using them?

 

[brianmoooore]

Don't caravans already have a 30mA RCD inside as well?

They should have, but the site owner can't guarantee that. Similarly, the connection point should have one, but the caravan owner can't be sure of that when he plugs in.

No idea as I rarely set foot in caravans, but would caravan users typically test the RCD on the power outlet when first connecting up? Is that in any guidance/best-practice that folks get for using them?

It's not always possible to access the RCD/RCBO/MCB, which is the reason I carry a selection of common enclosure keys when I'm on holiday.

 

[UNG]

I personally prefer to have ADS based on the OCPD whenever practical and keep the RCD for "additional protection".

It is often something that is lacking in circuit design these days back in the days of the ELCB you were always taught that the ELCB was the belt and braces backup

What seems to be lacking in most cases is any on-going testing of them. In spite of the test button. And stickers. And supplied documents.

A lot see it as an inconvienence to reset clocks and things in the home environment again in a caravan the RCD can be hidden away under a seat or in the back of a locker full of gear

Don't caravans already have a 30mA RCD inside as well?

Yes

No idea as I rarely set foot in caravans, but would caravan users typically test the RCD on the power outlet when first connecting up? Is that in any guidance/best-practice that folks get for using them?

On some hookup's it is difficult to access the RCD given the chance I always press the test button and sometimes break out the RCD tester for good measure

 

[mainline]

Why use an American site to make your point,

Cant see that it matters, the point is it happens.

There is an enormous faith placed on RCD's maybe it would be a no brainer to install two RCD's in series so if one fails the other might operate, all too often I find RCD's that operate outside of their specified ratings so how do you explain to someone that the safety device that was meant to protect them failed

I would rather explain that it was a failed component rather than a failure to fit one.

So we have poor design of the site and placing of the hookup's or a short hookup lead

There was nothing wrong with the siting of the hook-up as said my lead was short, the point is I still used it and if someone on a bike for example had not seen it then it could very well have caused damage to the hook-up.

In 40 years of camping and caravaning I have never seen it happen or seen the aftermath of it happening

I guess It's either you don't get out enough or it doesn't happen then ?

There is quite a lot of talk on the caravan forums of how they remind themselves to unplug, some put a peg on the steering wheel etc, so I guess they have to remind themselves for a reason.

Well, you saw the write-up and picture, so I guess you have seen it now.

I can see this will just go around it circles with you basically saying that an up front S type is not even worth considering, even though the plastic box which is basically mounted on a wooden spike and is divorcing the PME with some tape and a plastic gland has no chance of being damaged, and or the live conductor has no chance of coming in contact with the TT earth then happy days.

 

[UNG]

Cant see that it matters, the point is it happens.

TBH I doubt you even read that article as nowhere does it state the actual hookup point was damaged

I would rather explain that it was a failed component rather than a failure to fit one.

Thats your choice, I wouldn't want to be trying to explain why a safety component failed

There was nothing wrong with the siting of the hook-up as said my lead was short, the point is I still used it and if someone on a bike for example had not seen it then it could very well have caused damage to the hook-up.

It would probably have damaged the inlet on the van as well

I guess It's either you don't get out enough or it doesn't happen then ?

Going out with a short lead suggests you get out even less than I do

There is quite a lot of talk on the caravan forums of how they remind themselves to unplug, some put a peg on the steering wheel etc, so I guess they have to remind themselves for a reason.

And how many other checks are they not doing before leaving site

Well, you saw the write-up and picture, so I guess you have seen it now.

There was no site hookup point pictured in that article

I can see this will just go around it circles with you basically saying that an up front S type is not even worth considering, even though the plastic box which is basically mounted on a wooden spike and is divorcing the PME with some tape and a plastic gland has no chance of being damaged, and or the live conductor has no chance of coming in contact with the TT earth then happy days.

You are correct you are going round in circles, the chances of the scenario occurring as you describe is likely to be extremely rare to never and if the live conductor touches the TT earth why would the OCPD not disconnect the supply this is where the correct installation of earth rods comes to the fore rather than the half arsed "a 1m rod will do" approach that some take if it means installing enough rods to get the resistance to a level that allows the circuit protection to work as designed that why should that not be done

 

[brianmoooore]

Never seen a hook up that's been damaged by failing to disconnect, or by being driven into either. It's the 13 pin from the car that gets forgotten when parking up.
Can predict damaged hook ups from people not realising that the switch must be off before plugging in or unplugging the new type, though.
I carry two x 15m and 1 x 50m hook up lead. All three together have only ever been used once, when the whole side of the large site I was on went off. Full 80m right across the whole, and everyone around me wondered why one van still had full electricity.
Ended up with all the neighbours phones charging in mine.

 

[mainline]

TBH I doubt you even read that article as nowhere does it state the actual hookup point was damaged

Thats your choice, I wouldn't want to be trying to explain why a safety component failed

It would probably have damaged the inlet on the van as well

Going out with a short lead suggests you get out even less than I do

And how many other checks are they not doing before leaving site

There was no site hookup point pictured in that article

You are correct you are going round in circles, the chances of the scenario occurring as you describe is likely to be extremely rare to never and if the live conductor touches the TT earth why would the OCPD not disconnect the supply this is where the correct installation of earth rods comes to the fore rather than the half arsed "a 1m rod will do" approach that some take if it means installing enough rods to get the resistance to a level that allows the circuit protection to work as designed that why should that not be done

I'll sit and watch you sweat trying to get the RA low enough.

 

[brianmoooore]

Oooops! Wrong thread - deleted

 

[marconi]

Brianmoooore: You might want to discuss with the client having an energy meter for each 16A outlet. This is what I spec'd for my last client and he has found it useful to him and has avoided any arguments about how much electricity has been used during a stay. The metered hook ups were not much more than the unmetered ones. See:

LSAB 16A 1 Way Metered Caravan Hook-Up Unit - https://www.cef.co.uk/catalogue/products/4956834-lsab-16a-1-way-metered-caravan-hook-up-unit?gclid=CjwKCAjw1ICZBhAzEiwAFfvFhLGV5dhmE0aswgdxFO56RYk89XU1NDA9lBJrmI16gP6sZbAknffQ3xoCZA4QAvD_BwE&gclsrc=aw.ds

 

[brianmoooore]

The hook up featured in the link you have provided is only suitable for installation as a direct for an existing one. New points have to incorporate an interlocked switch, and are considerably more expensive, though I expect the inclusion of a meter makes a similar difference.
There's no reason why you shouldn't fit ones with a meter to keep an eye on consumption, or if you have a (illegal) long term guest, but for 'normal touring purposes, they're not a good idea.
Charging for electricity and charging for showers are excellent ways of killing repeat business.