near miss house fire

[SparkyTris]

immersion rated 3kW at 240V
fused at 45A, fuse had not operated
No cap was present (it had been removed to make a thermostat adjustment and never replaced)

fortunately the smoke was smelled and the fire extinguished before it had taken a hold (the cupboard was full of dry bedding, towels etc)

 

[ban-all-sheds]

Lucky escape.

The fact that there appears to be no damage whatsoever to the flex makes me wonder if it was an overheating problem, rather than anything which could have been prevented by more appropriate fusing.

 

[SparkyTris]

"seat" appears to have been the thermostat.
My feeling is that this was an overheating incident also.
I think that either:
the thermostat points became in some way faulty, went high in resistance, and generated sufficient heat at the point to cook-up.
or
one of the screw terminals of the thermostat was loose, became high resistance and cooked up.

it seems unbelievable, but the blue and brown wires' PVC coatings are melted together, but the conductors preserved sufficient insulation to not blow the fuse.
I tested the insulation L-N and E-L shortly after the incident, both indicated open circuit (albeit only at 9VDC)

 

[JohnD]

immersion rated 3kW...
fused at 45A

Why?

 

[Keithmac]

Should that not be fused at 13amps?.

 

[EFLImpudence]

Should that not be fused at 13amps?.

Not really. Some FCUs and plugs don't seem to like immersions.

15A fuse or 16A MCB is the 'normal' but it depends on the cable used.

Unlikely - but perhaps it's on an old shower circuit.

 

[John D v2.0]

Looks like some fire came from below, was that burning towels dropping down or parts of the heater casing?
Looks awful, really lucky there with so many combustibles around.

 

[333rocky333]

Was it heat resistant flex, I once had to have my flat wired by the council, after less than a week, the immersion blew and on removing the top, the wires insulation had melted and shorting to earth, it was standard flex.