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How does an over-heated pot of glass and plastic catch fire? If coffee-making machine are fire hazard, most homes in the world must be regularly burning. Given

How does an over-heated pot of glass and plastic catch fire? If coffee-making machine are fire hazard, most homes in the world must be regularly burning. Given that the overwhelming evidence, for example the fact that no house has burned in a large radius around my home, I'd say your and IBM's assessment is wildly off-target.

mcculley 4y ago
This was effectively a heating element without a switch. Yes, the risk is low. Still stupid to do it.
bena 4y ago
I assume in that bypassing the switch, it also bypassed the automatic shut off. Coffee makers are relatively simple designs. They're basically hotplates with a one way valve underneath for the water. Without the shut off, the thing would just keep getting hotter. And while heated glass will not catch fire, it can shatter violently. And those heated shards can then catch things on fire. And that's outside the fact that just faulty wiring can cause sparks and fire itself.
- hex4def6 4y ago
  They are simple things, but they don't go critical like you're describing. Simple ones often just have a mechanical bimetal thermostat device that opens / closes around a given temperature (a bit north of 100degC). In addition to that, they have thermal fuses that will blow if the temperature reaches over some threshold (I think 200degC?). My understanding is that they often use a pair of thermal fuses for safety. In this case, you would somehow need to have both thermal fuses fail closed, as well as the thermostat fail closed.
  - bena 4y ago
    But if I'm rewiring the thing to be on while plugged in, do you think I'm following the UL guidelines?
    - Nextgrid 4y ago
      The thermal fuses are typically built-into the heating element and are very difficult - if possible at all - to bypass. They are not part of the user-facing switch or whatever timer circuitry there is.
stonemetal12 4y ago
In my experience, coffee pot fires happen when there is a small amount of coffee left in the pot. It dries out, leaving a dark residue in the bottom. This residue catches fire.

mcculley 4y ago

This was effectively a heating element without a switch. Yes, the risk is low. Still stupid to do it.

bena 4y ago

I assume in that bypassing the switch, it also bypassed the automatic shut off. Coffee makers are relatively simple designs. They're basically hotplates with a one way valve underneath for the water. Without the shut off, the thing would just keep getting hotter. And while heated glass will not catch fire, it can shatter violently. And those heated shards can then catch things on fire. And that's outside the fact that just faulty wiring can cause sparks and fire itself.

hex4def6 4y ago
They are simple things, but they don't go critical like you're describing. Simple ones often just have a mechanical bimetal thermostat device that opens / closes around a given temperature (a bit north of 100degC). In addition to that, they have thermal fuses that will blow if the temperature reaches over some threshold (I think 200degC?). My understanding is that they often use a pair of thermal fuses for safety. In this case, you would somehow need to have both thermal fuses fail closed, as well as the thermostat fail closed.
- bena 4y ago
  But if I'm rewiring the thing to be on while plugged in, do you think I'm following the UL guidelines?
  - Nextgrid 4y ago
    The thermal fuses are typically built-into the heating element and are very difficult - if possible at all - to bypass. They are not part of the user-facing switch or whatever timer circuitry there is.

stonemetal12 4y ago

In my experience, coffee pot fires happen when there is a small amount of coffee left in the pot. It dries out, leaving a dark residue in the bottom. This residue catches fire.