Editing USB (section)

=== Ethernet ===
The ''IEEE 802.3af'', ''802.3at'', and ''802.3bt'' [[Power over Ethernet]] (PoE) standards specify more elaborate power negotiation schemes than powered USB. They operate at 48&nbsp;V&nbsp;[[Direct current|DC]] and can supply more power (up to 12.95&nbsp;W for ''802.3af'', 25.5&nbsp;W for ''802.3at'', a.k.a. ''PoE+'', 71&nbsp;W for ''802.3bt'', a.k.a. ''4PPoE'') over a cable up to 100&nbsp;meters compared to USB&nbsp;2.0, which provides 2.5&nbsp;W with a maximum cable length of 5&nbsp;meters. This has made PoE popular for [[Voice over IP]] telephones, [[security camera]]s, [[wireless access point]]s, and other networked devices within buildings. However, USB is cheaper than PoE provided that the distance is short and power demand is low.

[[Ethernet]] standards require electrical isolation between the networked device (computer, phone, etc.) and the network cable up to 1500&nbsp;V&nbsp;AC or 2250&nbsp;V&nbsp;DC for 60&nbsp;seconds.<ref>{{cite web | url = http://standards.ieee.org/getieee802/download/802.3-2008_section1.pdf | title = 802.3, Section 14.3.1.1 | publisher = IEEE | url-status=dead | archive-url = https://web.archive.org/web/20101206030247/http://standards.ieee.org/getieee802/download/802.3-2008_section1.pdf | archive-date = 6 December 2010}}</ref> USB has no such requirement as it was designed for peripherals closely associated with a host computer, and in fact it connects the peripheral and host grounds. This gives Ethernet a significant safety advantage over USB with peripherals such as cable and DSL modems connected to external wiring that can assume hazardous voltages under certain fault conditions.<ref>{{cite web|date=8 March 2010|title=Powerbook Explodes After Comcast Plugs in Wrong Cable|url=http://consumerist.com/2006/12/powerbook-explodes-after-comcast-plugs-in-wrong-cable.html|url-status=dead|archive-url=https://web.archive.org/web/20100625052120/http://consumerist.com/2006/12/powerbook-explodes-after-comcast-plugs-in-wrong-cable.html|archive-date=25 June 2010|access-date=22 June 2010|publisher=Consumerist}}</ref><ref>{{Cite web|date=2021|title=Technical Note. Galvanic Isolation|url=https://www.isystem.com/files/content/downloads/documents/technical-notes/iSYSTEM_TN_Galvanic_Isolation.pdf#page=4|website=iSYSTEM|format=PDF|access-date=13 February 2022|archive-date=21 December 2021|archive-url=https://web.archive.org/web/20211221080208/https://www.isystem.com/files/content/downloads/documents/technical-notes/iSYSTEM_TN_Galvanic_Isolation.pdf#page=4|url-status=live}}</ref>