Sun heat on caravan cable causing meter box circuit breaker to pop?

[TimGemm]

Could the sun’s heat on a caravan mains supply cable cause the fuse/circuit breaker at the meter box/supply end to trip?

 

[Rockingit]

Ok thanks ! Each time when that orange switch trips, I go to the cabin and turn the mains Off (supply into cabin). Then I try reset the orange switch in the meter box, but it keeps tripping. I leave if for 8-12 hrs and then it works. Does this suggest it’s either the circuit breaker or the cable? I have no idea what changes in the 8-12hrs so that it works……

That sounds more like a cable issue causing the RCD to trip - are there any joins anywhere where water or damage could have happened?

 

[Rockingit]

That sounds more like a cable issue causing the RCD to trip - are there any joins anywhere where water or damage could have happened?

Or the other way around - are there any ‘wet’ appliances such as a washing machine inside the cabin which could be taking that amount of time to dry out a fault? It’s feasible that if still plugged in but ‘off’ if you only have single pole isolation that it could upset an RCD. You’ll have to physically unplug every single last item from the wall next time it happens and see if the recovery time improves.

 

[TimGemm]

That sounds more like a cable issue causing the RCD to trip - are there any joins anywhere where water or damage could have happened?

Ok thanks. There are no joins or external damage but the plugs at both ends of the cable let some water in over time. There was corrosion inside the plugs particularly where the earth wire joins the plug. I have replaced the plugs, but I did notice that the earth wire copper core is now a darker colour of copper than the bright fresh looking copper colour of the other two wires. I cut a foot or so off each end to get rid of the worst of the earth cable, but the copper core is still a bit darker than the other two cores.

 

[Rockingit]

Ok thanks. There are no joins or external damage but the plugs at both ends of the cable let some water in over time. There was corrosion inside the plugs particularly where the earth wire joins the plug. I have replaced the plugs, but I did notice that the earth wire copper core is now a darker colour of copper than the bright fresh looking copper colour of the other two wires. I cut a foot or so off each end to get rid of the worst of the earth cable, but the copper core is still a bit darker than the other two cores.

Whilst it can also be caused by normal corrosion, what you describe instantly red flags with me as a heat/overload situation. If there has been current passing to the earth (in the U.K. we call that the CPC) then obviously that will generate heat - except if the terminals haven’t been done properly (eg aren’t tight enough) then you can end up with some arcing which is normally where that discolouration in the copper comes from.

 

[brianmoooore]

Whilst it can also be caused by normal corrosion, what you describe instantly red flags with me as a heat/overload situation. If there has been current passing to the earth (in the U.K. we call that the CPC) then obviously that will generate heat - except if the terminals haven’t been done properly (eg aren’t tight enough) then you can end up with some arcing which is normally where that discolouration in the copper comes from.

Not sure I agree, especially if it's the CPC that's deteriorated. The corrosion described sounds like that which is quite common on automotive cables. You find a damaged cable, find the blackened copper which wont solder, and have to strip back some distance to find reasonably bright solder that you can make a reliable splice to.

 

[TimGemm]

Whilst it can also be caused by normal corrosion, what you describe instantly red flags with me as a heat/overload situation. If there has been current passing to the earth (in the U.K. we call that the CPC) then obviously that will generate heat - except if the terminals haven’t been done properly (eg aren’t tight enough) then you can end up with some arcing which is normally where that discolouration in the copper comes from.

Are we talking New Zealand sun here?

It should be a specific cable for outdoor use.
Some domestic types, designed to be used in homes and buried in the fabric of the building will react to UV light over time, the plastic hardens and cracks.

The other issue could be overload. What size is the breaker, size of cable, load in caravan and distance between breaker and caravan.

Circuit breakers can also become weak over time… and will just trip for no reason.
From what I know of New Zealand electrics, is the meter box outside and maybe open to the elements? Has water got in somewhere?

Are we talking New Zealand sun here?

It should be a specific cable for outdoor use.
Some domestic types, designed to be used in homes and buried in the fabric of the building will react to UV light over time, the plastic hardens and cracks.

The other issue could be overload. What size is the breaker, size of cable, load in caravan and distance between breaker and caravan.

Circuit breakers can also become weak over time… and will just trip for no reason.
From what I know of New Zealand electrics, is the meter box outside and maybe open to the elements? Has water got in somewhere?

So it seems like the cable is damaged somewhere. Might have to replace. The max load is fridge + 2000W induction hob + 2000W oven. Cable is 100m long. Is 6mm2 cores enough? Cheers