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by klondike_ 1761 days ago
DC wiring is already standard in many office buildings in the form of power over Ethernet (PoE). It powers access points, lighting, and infrastructure, and high power variants can do 100W+. Since it's under 50V, the IT guy can install it without a qualified electrician. High power loads like motors and heaters will continue to require AC but I see no reason why small loads can't use PoE. I would love to see it take off for residential use, especially for IoT stuff.
2 comments
throw0101a 1761 days ago
> It powers access points, lighting, and infrastructure, and high power variants can do 100W+.

802.3bt Type 4 allows for sending 100W down Cat 6A cables, but only 71W is available at the other end. That's highly inefficient.

* https://en.wikipedia.org/wiki/Power_over_Ethernet#Standard_i...

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upofadown 1761 days ago
The loss is proportional to the length and ethernet cables are usually much shorter than the maximum length allowed by the standard.
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jwr 1761 days ago
PoE is great, but it's really a crutch: a workaround for when you can't run additional wiring. Its main advantage is that you don't have to use additional wiring.

The only reason PoE makes sense at all is because it uses 48V, but due to the flimsy cables the losses are still 15-20%. Not great.

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