EC328 shorting out mains supply

I have just connected my Auto Sleepers Lancashire to the main supply at my home.
When I switched on the EC328, it tripped the main RCD in my house.
I tried again - same thing happened.
Has anybody else experienced this?
What is the solution?
Thanks
Dave

Check hook up cable

If the OP is an accurate description, it's not likely to be a problem with the hookup cable - that would normally cause the house RCD to trip as soon as the EHU cable is plugged in.

You should be able to pin the problem down a bit further as follows: Unplug EHU, turn off the RCD and all of the MCBs on the EC328 main panel, reconnect the EHU and check that the house RCD has not tripped. Now turn on the EC328's RCD, leaving all of the MCBs off. If it trips then, the problem is probably internal to the EC328. If it has not yet tripped, turn on each MCB and check for tripping. From this you can work out which circuit, and hence which group of appliances, is causing the problem.

Roopert wrote:If the OP is an accurate description, it's not likely to be a problem with the hookup cable - that would normally cause the house RCD to trip as soon as the EHU cable is plugged in.

You should be able to pin the problem down a bit further as follows: Unplug EHU, turn off the RCD and all of the MCBs on the EC328 main panel, reconnect the EHU and check that the house RCD has not tripped. Now turn on the EC328's RCD, leaving all of the MCBs off. If it trips then, the problem is probably internal to the EC328. If it has not yet tripped, turn on each MCB and check for tripping. From this you can work out which circuit, and hence which group of appliances, is causing the problem.

Thanks Roopert - I'll be out of the country for a few days, but I'll try your check when I get back. Cheers!

Weird!!! I came back from holiday, tried Roopert's suggestion, switched on the EC328's RCD and, one by one, the three MCBs. The problem has "gone away"! I can't imagine what was going on. Thank you Roopert for the tip.

I hate to be the pessimist here but... I suspect it will be back.

In my experience, the only situation where such an issue could be temporary is where you have very high humidity, and condensation forms around electrical connectors. It seems very rare.

The other main type of fault - which can appear to come and go - is where the insulation within a heating element starts to break down. This type of fault can lead to a level of earth leakage that is ~just~ on the trigger threshold of and RCD - so sometimes it will trip and sometimes it won't.

I've had that type of fault on an immersion heater (in a building, not a van) and that was quite hard to track down. In that instance, the heating element was changed and the symptoms went away.

I now have the same problem, but my rcd's are not tripping. as soon as I turn on the mains switch on the sergent unit it flickers and then shorts all my electrics in the house, but as I say the rcd's are not flipping. I turn the main red light switch off before putting the electrics back on and all of my electrics still work, but I take it my leisure battery is not being charged, any suggestions please.

Ok - to be specific, the red illuminated switch at the top right of the EC328 is the Charger switch. The main incomer circuit breaker (which is a combined RCD and power switch) is on the left in the panel underneath that. The other three toggle switches in that panel are MCBs (they trip if current is too high, but are not sensitive to earth leakage).

Supply to the charger is routed as follows: EHU socket -> EC328 main RCD (on left) -> MCB 3 (on right) -> Charger switch -> charger.

So your conclusion seems correct. If it all works OK with EHU connected plus RCD and all three MCBs "On" but Charger switch "Off", and it trips the house main RCD when you turn the Charger switch "On", this points to an internal fault within the EC328. With the Charger switch off, the leisure battery will not be charged unless you are running the engine or have solar panel(s).

It may seem a little odd that the RCD in the EC328 doesn't trip, but if you look carefully you will probably find that both the house RCD and one in the EC328 have the same leakage rating - which means that either might trip first.

thanks for your answer, could it be a fault with the red switch.

If it's the RCD tripping, sadly not (unless, for example, it's sopping wet with water).

Assuming that it's only the RCD that ever trips, this indicates a fault to earth, and there isn't anything about a switch that can produce that sort of fault in realistic conditions. It's difficult to be certain without more rigorous testing, but it's quite likely to be a fault that's internal to the EC328, if the RCD trip occurs in exactly the conditions described above.

If the description wasn't completely accurate there are other things (external to the EC328) that could be the cause, but it should be possible to eliminate those other options if that's the case.

In a house it is usually an electrical heating element fault that causes the RCD to trip, and can take a long time to detect. You have to notice what electrical item is switched on at the time of tripping. It could be the washing machine, kettle, immersion heater, boiler, fan heater, even a blown light bulb. I would guess in a motorhome that it will either be the boiler electrical element or the fridge, or possibly but very unlikely the electric hob ring, if you have one. Heating elements immersed in water tend to corrode from the outside water covering them, inwards to the actual 'hot' wire inside the element. Then the live current leaks to earth causing the trip.
My personal experience of my Sargent electrics is that they were so badly wired that I removed all the mains connectors in the control box and hard wired everything, eliminating the stray strands of copper wire they left sticking out of the plugs and sockets. The bad wiring however only caused some mains items to not work at all, no circuit breakers were tripped.

Thanks for all your help. Bit the bullet this morning took the switch out checked all the connections, then took the cover off checked fuses connections and the wiring. no idea what was wrong but connected back up to electrics and it all works perfectly. Happy Days for the moment.