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Prototype of RTX 5090 Appears With Four 16-Pin Power Connectors, Capable of Delivering 2,400W (www.eteknix.com)
submitted 1 year ago by to c/technology@lemmy.world
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[–] 2 points 1 year ago (1 child)

That's a common misconception. It's the Amps that cause fires, not the voltage.

The 5090 uses 600W, at 12V that's 50A, but at 120V that'd only be 5A and at 240V only 2.5A.

50A melts cables and burns your PC down, 2.5A won't. The only risk of higher voltages is that they can jump across small air gaps much easier.

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  • [–] 1 point 1 year ago* (last edited 1 year ago) (1 child)

    No it's not, I'm an ee.

    P = I^2R, so power squares against the current, while it's linear to voltage.

    This means current causes more heat dissipation in the wire, which has risks, potentially fire if you really go too far, this is why breakers trip.

    But what really causes fires (again, outside of crazy overcurrent) is Arcing, from basically either bad connections or bad insulation, OR, from an inductive load that gets disconnected, so the current tries to stay constant in the coils, which leads to massive voltage spikes.

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  • [–] 3 points 1 year ago (1 child)

    The recent technology connections video cited a lot of statistics on this topic, and at least household fires are primarily caused by overcurrent, not by arcing.

    You probably know more than me — I only studied compsci with ee as minor — but from my personal experience, I've seen many cases where overcurrent caused damage, burns or fire, but I can't remember a single case where arcing caused actual damage.

    Even in cheap chinesium powerstrips, the primary cause of fires is overcurrent due to AWG 22 copper clad iron wire, not arcing. (Though the switches usually weld themselves together after a few dozen uses).

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  • [–] 1 point 1 year ago*

    Arcing causes more fires, because over current caused all the fires until we tightened standards and dual-mode circuit breakers.

    Now fires are caused by loose connections arcing, and damaged wires arcing to flammable material.

    Breakers are specifically designed for a sustained current, but arcing is dangerous because it tends to cascade, light arcing damages contacts, leading to more arcing in a cycle.

    The real danger of arcing is that it can happen outside of view, and start fires that aren't caught till everything burns down.

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