Electric heater plug just exploded - what would have caused that?

[pete01]

There hasn't been a short circuit just an overloaded fuse, so it wouldn't trip at the consumer unit.

Change the socket face and throw that heater away....well thats what I'd do.

 

[JohnW2]

Would have thought your consumer unit would have tripped. Any pics of that please?

It doesn't take much local heat (due to loose conductor connection or poor connection to fuse) to do thermal damage to a plug/socket, so that can happen with just 'normal' current flowing, hence no reason for an OPD to trip.

The terminal event which the OP observed (with "sudden hissing, spluttering noise and ... flickering flashes") could well have been due to arcing when something 'melted' and, again, not necessarily associated with anything more than 'normal' current.

I imagine that some people (maybe those with deep pockets!) would cite such events as a reason for having AFDDs - although, as in the OP's case, I think (but may be wrong!) that arcs commonly 'self-extinguish' fairly quickly, before they result in a fire.

 

[AndyPRK]

can't have an AFDD with a Ring. I guess the answer to that is to split it into 2 radials and spend even more money on AFDDs and large CUs

 

[ebee]

I do not like the name "PAT Testing" along with "PIN Number" Aggghhh.

Along with "One New Pence" or "One Pence" Aggggh again.

Along with puople using "PASSWORD" as their password

 

[JohnW2]

can't have an AFDD with a Ring.

I think one can, and the device will still detect and deal with 'parallel arcs' (between L&N or L&E, due to insulation damage/deterioration)) in the same way as in any other circuit.

The often mentioned 'issue' is that series arcs will not usually arise in ring finals, since, in the event of a break in one of the live conductors, current will flow through the 'other arm' of the ring, rather than trying to 'jump the gap' in an arc. Hence, whilst and AFDD will sometimes detect and deal with such faults in any cable (radial circuit, or connection/spur from a ring final) other than the ring cable of a ring final, it will not detect such a fault in the ring of a ring final.

However, since there is no arc when such a fault arises in the cable of a ring, there is no potential arc-related fire hazard - the only 'issue' being that, unlike the situation with any other cable, an AFDD will not detect and react to a break in the ring conductor (which theoretically increases the risk of cable overload) in the way that it might with any other cable.

Of course, if one is concerned about any of that, one doesn't have to use ring finals!