Small shock through caravan chassis

[Jez C]

This hopefully is of interest . I own a Swift Elegance and whilst on holiday felt a « zing » want of a better word through the jockey wheel and chassis. After reading a few threads and slightly concerned I checked both ends of my power lead only to find the earth on the end of my lead that connects to the site box was poorly wired or if at all!!
This has cured the current through the chassis but I ask the question as to why the rcd did not trip?
I’m interested as I have no idea at all🙈
Jez

 

[RogerL]

That needs more checking by a qualified electrician - if it was simply a faulty earth you wouldn't have noticed a problem and the fact that you've repaired the earth connection is good but shouldn't have made any difference IF the rest of the system was working properly.

 

[GUMPY]

There may not be anything wrong with the van. Lots of switch mode equipment like caravan chargers have EMF filtering which dumps down the earth wire, if the earth wire is disconnected then it finds another way to ground as you discovered. Its not enough to trip an RCD but you will still feel it.
I would still get the van checked but they might well not find anything

 

[ProfJohnL]

I agree with the two previous replies. And in addition, had there been a faulty appliance which was trying to put current through the earth wire, and you had made the connection either or possibly both the caravans and the sites RCCB/ RCD should have tripped. The fact that neither did trip, points to the tingle you got was a very high impedance or phantom leakage. Such effects are always worthy of investigation to eliminate anything wrong.

I also suspect that now you have addressed the poor connection in the EHU cable, an electrician will probably give the wiring a clean bill of health.

EHU's and extension cables that are frequently plugged and unplugged are significantly more vulnerable to connections working loose, so it might be worth checking them before going on a caravanning trip.

Its sometimes worth carrying one of these plug in testers(other makes are available) as they should detect a broken earth connection.

 

[Jez C]

I really appreciate the swift and helpful and informed response. I will get the van checked and will purchase the tester as suggested. Thanks 😌😌

 

[GaryB]

The quality of conductor connections have been driven down in parallel with cost. I've managed a technical and engineering department in the cable connector industry for over 25 years and what you've seen is sadly becoming more typical and I have always encouraged people with a bit of practical know-how to check any connections periodically. I have seen stranded earth conductors so poorly made where one of the strands was touching the live connector and also connections so poor that the high resistance joint caused the plug to melt.

 

[GUMPY]

One thing about 16amp connectors that seems to be missed is that if the connector uses screws to hold the cable, stranded cable should be fitted with bootlace ferrules to prevent the screw damaging the cores.

Personally I prefer the "quick connect" type of connector no screws, no ferrules needed and slightly more idiot proof