12v electrics working whilst vehicle in motion

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Since picking up my motorhome over a year ago I have always wondered why I cannot have 12v lights on in the back of the van whilst the engine is running. The electrical system installed has been designed so as to switch off any 12v supply, except the fridge once the motor has been started.
This sometimes can be a nuisance, when I have started the engine and the steps to the habitation area parks itself away, which means anyone outside wanting to get in the van has an almighty step up.

I recently needed a part for my EC200 charging control unit and accessed the Sargent Electrical Services site and downloaded a pdf of the appropriate unit. In the pdf I found the following statement:

EMC (Electro Magnetic Compatibility) directive 89/336/EEC requires that electrical accessories within the vehicle are disconnected while the vehicle is in motion.
Electromagnetic Compatibility - the EMC Directive 89/336/EEC, 1992 | ICT Regulation Toolkit

Briefly (and I mean briefly) going through the document, it babbles on something about radio interference!
Is this just euro babble for the sake of euro babble? Or am I committing an offence by altering my interior 12v system to allow a 12v supply whilst the vehicle is in motion?:confused:
 
in the olden days things would affect the radio, like wipers etc, so supressors were fitted. i cant think of any other reason not to allow lights to work while engine is running, but then im pretty thick so dont listen to me lol
 
From a quick skim, this looks like it's all to do with the Radiation some pieces of kit caused and that CE approval means that they comply with the relevant regulations.

Can't see anything about not being used when driving, but it was a quick skim. Your interior lights work in the car when the engine is on.

My MH has most of the internal fittings switched by the engine relay, however, there are two light fittings over the diner chairs that can be used ant time (as long as the leisure power is switched on!). Great when traveling so people can read, play cards etc.
 
Depending on how your van is wired, your fuses and 12V items may be subject to alternator voltage which can be as high as 15-16V or more. This may blow a fuse or damage a component which is sensitive to voltage.

That's the explanation I've seen of why the habitation electrics should be isolated when the engine is running.
 
If you look at the fitting instructions of most of the 12v fittings there is no mention of them having to be isolated when motor is running. In fact similar fittings can be found in powerboats where the motor runs most of the time.
I usually change the relay for a simple switch & if there is an issue with the interior lights being on at night there's also a switch called common-sense.
 
That's one reason why I wired my system with heavy duty switches instead of relays.

With a switch for charge and a switch for habituation electrics, I can have any combination of on or off when starting, stopped, or running.
 
European built vans still have 12 volt power in the hab area while the engine is running. I have to switch my power off at the control panel. Most of the time I do not bother.
 
Irritating as it, is not to be able to lower the step when the engine is running, it is in fact a very good safty related feature. Should you be able to have the step out whislt the engine is running, it follows that one day you might forget it and drive off with it out, only to either hit someone or something solid and wipe it off the side of the van. It can be disabled should you wish it I personally would not.

As to the habitation consumers turning off when the engine is running this is a tpyically english made motorhome thing. Seems Seargent and others are too lazy to gain the neccessary ce certification for their control boxes. As Pain Mate says most continental vans do not. There is a way to stop it but why bother as it takes only a few seconds to push the button to turn it on.
Wanderer
 
Usually most items will have no problem working off a few more volts and you are unlikely to damage anything. Lights may burn a little brighter and their working life reduced slightly. I think this applies to LED's used with higher voltage than rated too. I would be careful of running sensitive 12V electronics off the alternator though, just to be on the safe side. You could get a power surge when starting or revving the engine.
 
maingate said:
European built vans still have 12 volt power in the hab area while the engine is running. I have to switch my power off at the control panel. Most of the time I do not bother.
Click to expand...

Correct. 12v power at all times even with engine running.
 
My understanding of the situation is that it may be nothing whatever to do with the EU.

Rather it may be UK legislation that doesn't permit the use of lighting inside the vehicle at night. The easiest way to do this is to disconnect the 12v supply when the engine's running ...
 
Ok stupid thought time,regarding step with engine running ,simple solution by pass the switch and fit it to handbrake, that way the step retracts on handbrake off ,need to fit a lock switch so step doesnt extend on hill starts you have a light on dash saying handbrake on,ok need to think about a little more
 
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