Comment on Why is daisychaining multiple extension cords considered unsafe, even if only done to the length of a standard cable?

DragonsInARoom@lemmy.world ⁨2⁩ ⁨weeks⁩ ago

• kevincox@lemmy.ml ⁨2⁩ ⁨weeks⁩ ago

  To clarify a bit, the benefit of the UK system isn’t the end device having a fuse, but the cable itself having a fuse.

  In the US the setup would be something like

  1. Wall has 20A wiring.
  2. Electrical panel has 20A fuse to avoid the wire in the wall from overheating.
  3. Extension cord is designed for 10A
  4. You plug in 2 10A devices to the extension cord.
  5. The wall wiring is fine, it can take 20A.
  6. The circuit breaker doesn’t trip as it is also 20A.
  7. The extension cord overheats and starts a fire.

  In the UK the 10A extension cord will have its own 10A fuse in the plug. So when you turn on the two 10A devices the fuse in the extension cord will blow and prevent the extension cord from overheating.

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  • clockwork_octopus@lemmy.world ⁨2⁩ ⁨weeks⁩ ago

    Bold of you to assume that the wall outlet would have a 20a breaker. Most don’t, unless they’re in a kitchen.

    But you’re right about the resistance. Also, most extension cords are undersized for the loads they pull, they’re commonly made with 16 or even 18awg wire, further increasing resistance (which translates to heat).

    Source: am electrician in US

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    • kevincox@lemmy.ml ⁨2⁩ ⁨weeks⁩ ago

      The circuit power doesn’t matter for the example. I was just picking easy numbers. You can have the same problem as long as the rating of the extension cord is less than the circuit breaker. (And as you pointed that out this is a very common case due to the frequently low rating of extension cords.)

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