What would cause the burning on this plug?

[Spedley]

In the room in the loft an oil filled radiator tripped out the RCD and had this burn mark on the plug. There is no damage elsewhere and the socket appears fine and functions as normal. Any ideas what the cause is from the burn mark? Is it the radiator, the plug or the socket or something else?

Untitled

• Spedley
• 29 Dec 2014
• 1

 

[Spark123]

Probably a loose or bad connection with the plug and socket, I'd replace both.

 

[PrenticeBoyofDerry]

Could also be a loose or bad connection within the plug, that is causing heat to be dissipated.

 

[Spedley]

Had a look at the socket and it looks ok jnside although it is quite old. Tried it with a lamp and it works fine but plugged another heater in and it trips out.

 

[PrenticeBoyofDerry]

If RCD is tripping out, try the heater in another socket on the same RCD. This could hopefully eliminate the heater and then investigation of the socket would be required, could be a contact problem.

 

[ban-all-sheds]

OK - how does a loose N connection, or dodgy N pin contact, cause an RCD to trip?

 

[bernardgreen]

OK - how does a loose N connection, or dodgy N pin contact, cause an RCD to trip?

Scorched and charred insulation inside the plug with the carbon creating a path between earth and one of Live or Neutral

But why the RCD tripped when a different heater was plugged into that socket is another question.

 

[JohnW2]

OK - how does a loose N connection, or dodgy N pin contact, cause an RCD to trip?

Although, in the absence of large reactive loads, it's very difficult to propose a mechanism, we do seem to repeatedly hear reports of loose connections (or even DP switches) apparently leading to RCD trips - so maybe it's not actually myth, even if is does defy my ability to explain!

Kind Regards, John