IRIO Failure

[John W]

I noticed via the comfort app last night that my system was reporting an RS485 comms failure with an IRIO.On investigating today, I\'ve had a small fire hock:
This panel is in a metal sealed/vented enclosure that controlls some of the garden lights.The board takes its logic power over cat5 from the main panel.The mains is supplied by an MK RCBO 6Amp (didnt trip)I can switch all the lights independently using mains switches and they all work fine.These lights havent been switched on recently.
It looks like something on the Relay Sub board has let go, and created a small fire.I\'m not sure if the IRIO carrier board is damaged electrically. Its socket upstand is a bit melted. Both sub boards had their power leds on. 
So, the questions are:-should I expect this sort of failure ?-if I replace the boards what is to say it won\'t happen again ?-Would just the failure of a single sub-board cause it to report a comms failure, or is the main board damaged too ?[sub][/sub][sup][/sup]-Chiu do you want more info to investigate ?-is there any good will discount / replacement on this ?
I will attached some pictures in a moment (already written all this once to then fail on attachment and lose it all )
Cheers,     John.

[John W]

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[John W]

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[John W]

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[Swiss-Toni]

Before I start Im not critising the installation, but that has been caused by a short, looking at the photo\'s the likelihood is that it has been caused by moisture causing a bridge and arcing out the board.
When dealing with equipment like this it cannot be istalled in damp locations, if it has to be then an enclosure should be built around it to seal the comfort panel against any moisture getting in.

[John W]

Thanks swiss-tony.
It is in an ip rated Himmel enclosure with a gasket sealed door.
The mounting bolts have rubber washer around the bolts both sides, the top of the cabinet has no holes in it, the top rear of it is shielded to stop moisture getting down the back.
An alloy carrier panel is fitted inside to the mounting bolts, which has a Stego 8W NTC enclosure heating element to ensure it doesn\'t get too cold in winter, and meant to stop condensation.
A stego vent plug is fitted in the bottom of the enclosure. All cables enter the enclosure through the bottom using glands (all mains ones are armoured cable, only other one is underground grade cat5+).

The carrier panel has DIN rails on it (all my panels do incase they are needed for localised din mounted devices), but the comfort pcb is mounted using plastic stand offs.

What did I miss ?

Thanks,John.

[Swiss-Toni]

Looking at the first picture you can see rust which indicates moisture is getting in somewhere, I cant say where it is getting in, I can only go by what I can see, it only takes a drop to cause catastrophic problems, I would say there is a distinct possability of it happening again under those circumstances in my opinion....

[John W]

Your right, there is a bit of surface rust. This box used to have a switch panel in itbefore I fitted the IRIO, and it didn\'t have a heater in it then, or a vent plug.
I will give it a pressure washing, see if any water gets in.Assuming it doesn\'t, what else should I be doing or looking for ?Like I said, what have I missed ?
I have two other cabinets that have similar setups although they use RIOs and relay boards. No surface rust at all in them.
Any suggestions gratefully received.

[Swiss-Toni]

Other than moisture creating the problem, other posibilities elctrical strands faulty components the list could be potentialy endless the boards touching, but from what i can see the fault lies in arcing (shorting out). other than what I have said and seen I could not suggest anything at all.