Caravan Site Hook Ups

[westie101]

Now most sites in this country supply a 16A hook up, which matches the ratings of the plug/socket and cable sizes.

But how do they ensure the 16A max is complied with?

Most bollards are protected by an RCD/MCB combination which is fine, but to operate for load the MCB must trip on it's thermal rating which can be higher continuously than the actual rating

Is there a MCB type where the rating and actual thermal rating match?
Is a smaller MCB fitted so that it then operates at the thermal rating?

 

[Lectrician]

They all have very cheap B16 Mcbs fitted, with no more than three protected by an RCD. (or with the 17th, an RCBO for each outlet).

Some sites limit it to a B10 or B6, but that's fairly rare in my experience.

 

[AdrianUK]

We dont have a caravan, but do go camping with our tent.

Her indoors always insists on an electric hookup.

The quality of what I find varies enornously! Most seem to have bog standard 16A RCBOs, 4 to a pillar, fed single phase. Others, expecially older coastal sites have 10A or even 6A MCBs with a shared RCD.

I've managed to have a peek in the distribution cabinets of a couple and found that those feeders where fed with TP C40A MCBs serving 3 to 6 boxes each with 4 x 16A outlets ...... guess captain diversity is at play here!

So, to answer you question .... they dont ensure that the max stated power is complied with. I've never yet come across a site where the MCBs/RCBOs are not freely accessible.... so, it it does trip, you simply reset it! Walking around these sites on the chilly evenings reveals that most tents have at least 1 off 1800W infrared heater. We have a 1500w ruggedised fan heater plus the usual domestic kettle & a few lights. Sometimes, when we forget to turn the heater off & boil the kettle it will trip the supply, if its a 10A MCB, but often the kettle will boil before the MCB has even started to warm up its thermal trip.

I've been told by friends of a couple of sites which have had problems on the really cold nights, with the site owner having to sit next to the 250A TP MCCB and keep resetting it, but, by & large, it seems to work out fine.

Some sites are now moving over to metered supplies on the pitches... guess that will cut power consumption!


Adrian

 

[securespark]

Some sites limit it to a B10 or B6, but that's fairly rare in my experience.

I've seen B10 a few times.

 

[ericmark]

I was told rules for touring vans as different to static told the latter has to have at least a 32A supply.

But touring vans and narrow boats can have as low as 4A supply. The narrow boat will often have a step battery charger and an inverter so it will draw the max.

708.553.1.10 The current rating of socket-outlets shall be not less than 16 A. Socket-outlets of higher current ratings shall be provided where greater demands are envisaged.

708.553.1.12 Each socket-outlet shall be provided with individual overcurrent protection.

708.553.1.13 Each socket-outlet shall be protected individually by an RCD having the characteristics specified in Regulation 415.1.1. The device shall disconnect all live conductors including the neutral.

Twin pole RCBO would seem to be the way to comply but we all know older sites have not up-graded.

If we are faced with either no hook up or a 4A hook up most will take the 4A. The supply to many sites is just not good enough to give the full 16A.

 

[Spark123]

The regs take into account a fusing factor of 1.45 when selecting cables etc, your 16A socket will be fine with 16x1.45 amps being drawn through if for up to an hour.
There isn't any MCBs out there that I am aware of with a fusing factor of 1.

 

[bernardgreen]

It would be possible to fit current transformers on the supplies to monitor the current taken and use that to turn power off when the agreed limit was exceeded. The trip level could be set very accurately.

 

[westie101]

Thanks for the answers, this comes from discussions elsewhere where sites are losing supplies through overload to the whole system. (in some cases blowing fuses at DNO substations.
It usually happens at a cold early Easter.

It confirms my view that some units are probably using more than 16A for short durations which will not help the situation

 

[ericmark]

Using motor overloads one could set the overload finer but the cost would be prohibitive. I think the problem was traditionally they could provide a 6A supply but the 2008 regulations changed that which means they just fitted 16A rather than 6A but did noting to uprate the supply to the site.

With shower blocks as well often electric heated they are often well over there capacity. I know one who fitted a moulded braker to ensure that tripped before main fuse.

 

[AdrianUK]

Westie,

I'd agree with that. Since the supplies are unmetered there is no incentive to turn off heaters when not needed nor to ration the power in any way.

We too are guilty of sitting out under the chilly night sky, staring up at the stars while being warmed by 2800W of infra red heater!

Electric hookup seems to be almost an essential nowdays with many sites expanding and simply just connecting more & more pitches to an incommer that has probably not been upgraded to cope. I know of at least one 30 pitch site in north Notts that still operating on a 100A splt phase rural supply!

It would be interesting to find out what sort of diversity figures these sites are actually operating at ... I can imagine that it could easily be 2, 3 or may be 4 times capacity .... fine during the summer months ...but over the autumn/spring period......

Having looked around sites we have visited, I can understand why the overload gets to the level of taking out the DNO fuses .... most of the load is going to be heaters .... and they will run from dusk until very late, perhaps even all night (we do in the tent) so there must be alot of cutout fuses getting very warm.....