Can we supply 2A DC current at 5V in the pair of ethernet CAT 5e cable?

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    \$\begingroup\$ Are you asking just about how much current can be passed through a wire, or are you planning some kind of power-over-ethernet scheme? Also, can you specify the gauge (diameter) of the actual wire in question? \$\endgroup\$ Commented Jan 18, 2019 at 13:38
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    \$\begingroup\$ See also: This, and this \$\endgroup\$ Commented Jan 18, 2019 at 13:44
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    \$\begingroup\$ It is possible for a CAT 5e cable to be as thick as 22 AWG or as thin as 26 AWG, so the actual wire size needs to be specified. Will the cable run inside a wall or plenum? \$\endgroup\$ Commented Jan 18, 2019 at 15:09
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    \$\begingroup\$ this question also seems similar: electronics.stackexchange.com/questions/113253/… . If you do any kind of quick google search, you'll find that a) 24AWG wire in a CAT5 isn't meant for currents that high and b) you will probably have a voltage drop issue. \$\endgroup\$
    – I. Wolfe
    Commented Jan 18, 2019 at 15:42
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    \$\begingroup\$ You can supply 10 watts over a pair of conductors in cat5, but not at 2A 5V. In order to get a reasonable voltage drop over any practical distance, you need higher voltage, lower current. Consider voltages up to 48v (still touch safe) with a buck converter at the far end (many converters are available that do 48v down to 5v, it's a really common requirement) \$\endgroup\$
    – Neil_UK
    Commented Jan 18, 2019 at 16:10

1 Answer 1


CAT5e cable has 22AWG (at most) wire in it and could have 26 awg, this means that the cable has a resistance of up to 16 ohms per 1000ft. A 10ft section would have 0.16Ω, at 2A this would cause a loss of 0.32V one way, with a total voltage drop of 0.6V.

This would probably not be enough voltage to run your device as it most likely requires 5V, not 4.4V. The other problem would be that the voltage drop would fluctuate with the current causing problems for the device.

With 26 AWG the problem gets worse as it's resistance is 40Ohms per 1000ft and would cause an even bigger drop.

So the answer is, probably not it depends on the length and the wire gauge of the cable. If you do it would be best to have a regulator on the device end or some other way to keep the voltage above 5V.

POE works by scaling up the voltage and running low current and by running AC power, not DC.


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