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The UKHA-ARCHIVE IS CEASING OPERATIONS 31 DEC 2024

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Re: Re: Current carrying capacity of CAT5?




rectorydp wrote:

>
> When I (sort of) answered this question back in August, I couldn't
> find a previous reference in UKHA_D. Since then it has been asked
> several times!
>
> My response at the time was as follows.
>
>
Just want to add  the voltage drop calculation for AWG-24  to this.

AWG-24 has a resistance of 87.5 ohm/kilometer ( at 20 degrees Celsius)
Ohms law is U = R * I

So if we have 10 meters of cable it will have a resistance of 0.875 ohm

If we would like a current of 400 ma at the remote point we will get a
voltage drop of 0.4 * 0.875 = 0.35 V. Extend the cable to 100 meters and
this drop will be 3.5V

From this we see that we need to feed  a voltage that is a bit higher
into the cable then we can take out at the remote end.

/Ake




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