Electric hook up

Jun 17, 2018
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As I stated my caravan is on my drive should I keep it hooked up to the house for safety reasons like the fridge and keep battery topped up what are your thoughts on this ?
 

Parksy

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Nov 12, 2009
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There's no harm in keeping the caravan hooked up to the 230v supply while you are at home, you can put the electric heating on now and again to keep condensation at bay and the leisure battery will stay topped up. There's no need to switch the fridge on, just leave the fridge door ajar when it's switched off.
 
May 24, 2014
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I had a sparky put me a bollard in at home to hook up to properly. I leave mine on all the time, always have. As Parksy says, you can put the heating on whenever you feel it necessary. the fridge doesnt come into it unless you have food in there, normally it would be off. However, as we have a large xmas gathering at ours every year, the fridge gets used to stock some of the festivities food.

One point of note, as some here may remember, last year I got a shock when putting the heating on in particularly cold weather and forgetting to open the cupboards, the amount of condensation was horrendous. lesson learned.
 
Jan 19, 2002
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I also keep mine hooked up to an out let within my garage. The fridge is carefully washed out after each trip and the door AJAR to prevent any mustiness or mould.
 
May 7, 2012
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When we had the caravan at home I connected the caravan up to the mains from time to time to charge the battery using a converter for the 13 amp house mains plug. The battery does not need to be on a continuous charge so an external hook up is not needed.
 
Nov 11, 2009
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Raywood said:
When we had the caravan at home I connected the caravan up to the mains from time to time to charge the battery using a converter for the 13 amp house mains plug. The battery does not need to be on a continuous charge so an external hook up is not needed.

I do likewise too.
 
Oct 3, 2013
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Don't understand this - what "safety" reasons are being considered here.
Our van is alongside the house but not permanently connected to any mains supply.It seems like a waste of power to keep the van powered up from the mains all the time.
We just power up the van the night before to cool down the fridge and keep the battery in good nick for using the motor mover.
 
Oct 17, 2010
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Have my hook up on a timer, switches on for a couple of hour in the evening, fridge is normally off. A few years back when we were younger, would use both fridge and cooker, to help with Christmas festivities, so EUH on all the time for a few days..
 
Mar 14, 2005
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bertieboy1 said:
Don't understand this - what "safety" reasons are being considered here.
Our van is alongside the house but not permanently connected to any mains supply.It seems like a waste of power to keep the van powered up from the mains all the time....

Like wise I don't fully understand the reference to "Safety"

But simply having an EHU connected is not wasteful of power unless you leave something turned on inside the caravan.
 
Aug 11, 2018
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I connect to garage supply, normally fridge left running until got around to empting it, caravan is used as an extra room. However safety wise there are a few considerations.

1) Should a battery have a shorted cell it could damage the charger and if not realised could explode, think unlikely but it could happen.
2) If following IET regulations the supply to caravan should be TT, however I have not bothered, it has a TN-c-s supply which technically does not comply.

As an electrical engineer I think on balance better connected to a supply, than not, however it is not correct if I followed regulations.
 
Nov 11, 2009
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ericmark said:
I connect to garage supply, normally fridge left running until got around to empting it, caravan is used as an extra room. However safety wise there are a few considerations.

1) Should a battery have a shorted cell it could damage the charger and if not realised could explode, think unlikely but it could happen.
2) If following IET regulations the supply to caravan should be TT, however I have not bothered, it has a TN-c-s supply which technically does not comply.

As an electrical engineer I think on balance better connected to a supply, than not, however it is not correct if I followed regulations.

What is TT?
 

Damian

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Mar 14, 2005
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TT is a system having one point of the source of energy directly earthed, the exposed conductive parts of the installation being connected to earth electrodes electrically independent of the earth electrodes of the source.

Does that answer you?

The TN-C-S system in which the neutral and protective functions are combined in a single conductor in part of the system.
 
Aug 11, 2018
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Supply to boats, caravans and petrol stations are not allowed to be TN-C-S as under fault conditions the earth supplied from the DNO (company supplying electric which may not be billing agent) may not be true earth, C = combined S = Separated so for part of the cable run to your house the earth and neutral is combined but by time it reaches your house separated again. Although TN-S is allowed we have no control so the DNO could change it without notice.

As on a caravan site the posts supplying power have an earth rod for the earth, and fire regulations means buildings have to have some distance between them and the caravan.

Problem at home is the caravan can be close to the house, so having a different earth system could cause danger, as items earthed to house could have a different voltage to that of the caravan, so there is just as much danger having different earthing system as having both house and caravan with TN-C-S system. This has be recognised with electric cars so at home supplies to electric cars has become a specialist subject.

The ultra save method would be an isolation transformer, however most battery chargers are fitted with isolation transformers and are often a Class II supply (no earth connected) so the most cost effective way would be a battery charger with a 13 Pin socket plugging into the caravan car plug so only a 12 volt supply.

However I want to run fridge and central heating in the caravan so fridge is cold before we set off and caravan has had chance to dry out, so I break the rules and plug caravan into the garage. I feel the risk is very low, so I use the TN-C-S supply, as caravan is not lived in at home and access is from a paved area so very unlikely we would ever access under fault conditions and even if we did the paving would offer some protection, and really too close to garage to have a different earth system.
 
Nov 11, 2009
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ericmark said:
Supply to boats, caravans and petrol stations are not allowed to be TN-C-S as under fault conditions the earth supplied from the DNO (company supplying electric which may not be billing agent) may not be true earth, C = combined S = Separated so for part of the cable run to your house the earth and neutral is combined but by time it reaches your house separated again. Although TN-S is allowed we have no control so the DNO could change it without notice.

As on a caravan site the posts supplying power have an earth rod for the earth, and fire regulations means buildings have to have some distance between them and the caravan.

Problem at home is the caravan can be close to the house, so having a different earth system could cause danger, as items earthed to house could have a different voltage to that of the caravan, so there is just as much danger having different earthing system as having both house and caravan with TN-C-S system. This has be recognised with electric cars so at home supplies to electric cars has become a specialist subject.

The ultra save method would be an isolation transformer, however most battery chargers are fitted with isolation transformers and are often a Class II supply (no earth connected) so the most cost effective way would be a battery charger with a 13 Pin socket plugging into the caravan car plug so only a 12 volt supply.

However I want to run fridge and central heating in the caravan so fridge is cold before we set off and caravan has had chance to dry out, so I break the rules and plug caravan into the garage. I feel the risk is very low, so I use the TN-C-S supply, as caravan is not lived in at home and access is from a paved area so very unlikely we would ever access under fault conditions and even if we did the paving would offer some protection, and really too close to garage to have a different earth system.

Thank you for your final paragraph, as reading up to your paragraph four I was ready to go out and disconnect the supply to the caravan. Yesterday I fitted new gaiters to the mover so connected the van up to test the mover rotation and give the battery an overnight boost.
 
Aug 11, 2018
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Gafferbill said:
.........I put my faith in a residual current curcuit breaker rather than paving slabs :lol:

The fault why TN-C-S is not allowed is when the combined neutral/earth is lost and as a result the earth becomes live, since you have no way to switch off the earth, no RCD, Main Switch, MCB or RCBO will help, only thing you could do is unplug.

It is very rare that the combined neutral/earth is lost, and when it is lost voltage can vary zero to 400 volt so it does loads of damage as well as shock risk, so the odd time is does happen tends to get well published.

Here are some examples the big problem is where the earth to gas pipes causes the gas pipe to melt, and most of the damage shown is due to missing isolation or shorted isolation on gas supply.

However these problems are rare so in real terms I do not worry about plugging caravan into my garage supply.
 
Apr 6, 2017
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Ericmark.
You have made me think! So there is a real danger of electric shock from a caravan if there is two separate faults occurring at he same time. i.e. the lose of the earth connection via the hook up cable and an earth fault within the caravan. The body of the caravan could become live assuming there isn't an earth circuit created by the legs in contact with the ground making a good earth (plastic stacker feet).
Unlike a house where the services provide a secondary earth connection along with the rising main amour . An RCD would be useless in this situation as the live and neutral currents would be in balance.
So, should we have an earth rod stuck in the ground and lashed to the caravan chassis?
Surely this could result in "our' earth connection becoming the principle earth point for the locallity and could be subject to enormous earth currents. The isolating transformer and local earth point is the solution as used shore side on boats.
 
Mar 14, 2005
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GD485 said:
Ericmark.
You have made me think! So there is a real danger of electric shock from a caravan if there is two separate faults occurring at he same time. i.e. the lose of the earth connection via the hook up cable and an earth fault within the caravan. The body of the caravan could become live assuming there isn't an earth circuit created by the legs in contact with the ground making a good earth (plastic stacker feet).
Unlike a house where the services provide a secondary earth connection along with the rising main amour . An RCD would be useless in this situation as the live and neutral currents would be in balance.
So, should we have an earth rod stuck in the ground and lashed to the caravan chassis?
Surely this could result in "our' earth connection becoming the principle earth point for the locallity and could be subject to enormous earth currents. The isolating transformer and local earth point is the solution as used shore side on boats.

Hello GD45,
Given the possibility of two consecutive faults arising in a caravan yes there is the potential (no pun intended) for the caravan body to be come live. But it has to be said the chances of a double fault are pretty rare, but not impossible. However the supply to which the EHU is connected should have earth fault protection devised like RCD's which should also operate should the double fault occur and someone makes the body to ground connection.

That's why it's always important to check the function of the RCD with the test button after you make a power connection - it proves your EHU connection..

Ultimately if someone is determined they can create situations to defeat the protective devices, but , where what ever protective devices are fitted
 
Feb 7, 2010
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I keep mine on the drive. It is plugged in at the moment with only the heating on and set at 9 degrees to stop any chance of the pipes freezing. I don't see any problem with it being connected for long periods of time. At Bonterra Park there are people there from September to April and they never seem to get any problems. I have removed the fuse from the solar panel as I think being on hook up that will keep the battery charged without using the solar panel.

Les
 

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