How does a moulded plug just fail?

Robin0577

Robin0577

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Moulded 13A plug belonging to a dishwasher from a reputable European manufacturer, not some dodgy ebay import. Date stamped 03/12, permanently plugged in and has suffered no abuse that I'm aware of.

No sign of damage, overheating, burning, liquid stains, etc.

Only symptom: Dishwasher trips RCD

View media item 93940
Any idea how an undisturbed lump of moulded plastic suddenly becomes conductive after 3 years??

Somewhat annoying as I went to the effort of desoldering and replacing the Y2 line-eatrh RFI capacitors before discovering they weren't to blame!

P.S. Obviously I'll dispose of it safely such that it can't be plugged in.
 
My bet is the cable has shorted at the entry to the plug.

DS
 
I had a moulded plug that caused spectacular smoky shorts and trips after dirty water got into it.
 
AIUI a moulded plug is made by first manufacturing a base with pins. fuseholder etc (this is the black bit in the OPs photo), then the wiring is crimped on and then finally the body and strain relief of the plug are moulded around the base and wiring.

Sometimes the joins between the different parts are not as good as they could/should be. I've seen a moulded IEC connector where the sheath of the flex had pulled completely out of the moulded body leaving the connector hanging by the inner cores. In less extreme cases i've seen moulded connectors (both BS1363 and IEC) where the cable was noticablly loose inside the strain relief.

So it wouldn't surprise me if there are some cases where a moulded plug has cracks big enough to allow liquid in.
 
Robin0577 said:
a reputable European manufacturer,.
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may buying component parts such as mains leads from suppliers whose quality standards are not maintained once the contract has been signed after thorough tests and inspection of samples in Europe.

Samples and first few batches will be made in the factory and the European manufacturer is happy. Then production can be moved from the factory and put out to outworkers working on their kitchen tables.
 
The other thing that could have happened is a poor connection on one of the pins when plugged into the socket causing a heating effect of the plug. Maybe worth investigating the socket as well.
 
Taylortwocities said:
cajar said:
Cut it open and find out
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Go on, you know that you want to…. :lol:
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I've tried it a few times, and if the plug has been well made (in the moulding sense), it can often be next-to-impossible to removed the moulded material without damaging/destroying the 'evidence' one hopes to find. It simply isn't (or shouldn't be!) as simple as "opening it"!

Kind Regards, John
 
I recall one where it appeared to be the compound breaking down, wether through damp i dont know but meggaring it showed a reading when prodding it.
maybe hacksaw into two parts then you may see something
 

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