- Reaction score
- 13,478
One can usually tell whether the heat has originated at the pin/socket contact, the fuse contact or the flex terminal. Unless the plug is corroded, dirty or is not of correct manufacture, any heating at the pin/socket contact is invariably the fault of the socket because that determines the contact pressure. Any heating at the screw terminal is invariably the fault of the whoever wired it.
Sometimes heating at one point causes oxidation and loss of contact spring temper at another, creating a domino failure. An overheated fuse contact can heat the line pin and cause the socket contact to fail, or vice versa. It is not always obvious which is the original culprit, but there is an ever-present source of heat in the fuse element that works quietly behind the scenes to accelerate the age-related rise in resistance at its end-caps and set the whole process off.
Regarding the inspection of overmoulded cable terminations, I don't see that it's any different to any of the other hidden connections in the circuit. You can't inspect the spot-welds in the MCB or the rivets holding the current-carrying parts of the socket together, nor some of the ones in the appliance. The sealed casing of the dryer's cheap little heater relay hides two riveted and two spot-welded connections carrying the same current that destroyed the plug, with the aggravating factors of the contact heat dissipation and movement to show up any weakness.
Sure, fake and unapproved cordsets can be quite horrendous and deserve their reputation, but the captive cable and plug fitted to a brand-name appliance is not likely to be one of those so we can largely exclude that sector of the failure pie-chart from the present discussion.
Sometimes heating at one point causes oxidation and loss of contact spring temper at another, creating a domino failure. An overheated fuse contact can heat the line pin and cause the socket contact to fail, or vice versa. It is not always obvious which is the original culprit, but there is an ever-present source of heat in the fuse element that works quietly behind the scenes to accelerate the age-related rise in resistance at its end-caps and set the whole process off.
Regarding the inspection of overmoulded cable terminations, I don't see that it's any different to any of the other hidden connections in the circuit. You can't inspect the spot-welds in the MCB or the rivets holding the current-carrying parts of the socket together, nor some of the ones in the appliance. The sealed casing of the dryer's cheap little heater relay hides two riveted and two spot-welded connections carrying the same current that destroyed the plug, with the aggravating factors of the contact heat dissipation and movement to show up any weakness.
Sure, fake and unapproved cordsets can be quite horrendous and deserve their reputation, but the captive cable and plug fitted to a brand-name appliance is not likely to be one of those so we can largely exclude that sector of the failure pie-chart from the present discussion.
