Habitation lights

[Suda]

Hi helpful technicians.

We have a 2008 Burstner Travel Van 620. There is a problem with one of the light circuits in the habitation area. The fuse blows after we have been on the road for about 3 days

. Having replaced the fuse all appears fine then it goes again. I’ve stopped replacing it now as we can manage without those particular lights. But I’m concerned that there could be a fire risk .

The replacement fuses are the same type as the ones removed. This problem has occurred both on and off hook up.

We have 2 leisure batteries and a solar panel if that helps.

Thankyou

[BruceM]

I take it that this is a new fault and the lights were working perfectly ok before?

 

Is there any consistency as to when the fuse blows?

 

For instance, does it blow when the lights are already on or is it at the point at which the lights are turned on? And does it blow immediately you arrive at a destination and turn on the lights or can it happen whilst you’ve been stationary for a day? What I’m thinking is that if it blows sometimes when switched on then it might be an intermittent short on the switch (so worth investigating). If it’s when the lights have been on for a while it implies overloading of the circuit which unless you’ve recently changed a bulb for something that’s too high a wattage then it’ll require some multimeter investigation.

[plwsm2000]

Sometimes (not always) the condition of the (blown) fuse can give an indication to the type of fault you have had (either a sudden short or a bit more of a "slow burn"). If the fuse element has completely disintegrated and maybe there are balls of once molten metal inside (the debris of the fuse element), then this can suggest the fuse has seen a very large and sudden overload such as a short circuit.

 

If the fuse element is just discoloured and some of the fuse element is still present (but obviously broken) this suggests that the fuse has seen more of a moderate overload rather than a short. You may also see evidence of the plastic housing melting.

Although you should not rely on it, the automotive "ATOF" or "UniVal" blade fuses can normally withstand an overload of around 10% indefinitely. At 25%, they can take several minutes/hours to open. At twice the current, they can still take a few seconds to blow. As Bruce said, it would be best to measure the current and check it is not too high.

 

I have had my fingers burn (literally) by cheap fuses bought by the kilo (almost!) in poundshops as they are too unpredictable. I now only use branded fuses such as Littelfuse or MTA

[aandy]

I had a similar problem. All was well while parked up, even for several days, but if I drove for more than a short distance the fuse would blow. As movement was obviously the key I figured it was most likely a problem with the wiring, so waited until dark then poked and prodded every bit of the loom that I could get to. A small flash indicated where part of the loom had been rubbing against a flange in the cab structure and had chaffed through the insulation. A simple fix, but I had to do a fair bit of dismantling to get at it.

[tonyishuk]

A thought ? Have you upgraded thr original bulbs to LEDs ?

 

In some LEDs have a rectifier curcuit to ensure the led gets the correct polarity to light. There is a possibility. That the rectifier is failing under load and causing a short circuit.

 

Rgds