Regulations controlling 24VDC power distribution

G

Thread Starter

Greg

I have a need to distribute 24 VDC over a long distance (300ft or so) using a flexible cable. Are there any codes that I should be aware that limit me to distances, types of cable used, will it need to be in a conduit? Are there any other issues I need to be aware of besides voltage drops when distributing 24vdc power? This will be used in an Industrial Automation environment.
 
R

R A Peterson

> I have a need to distribute 24 VDC over a long distance (300ft or so)
> using a flexible cable. Are there any codes that I should be aware that
> limit me to distances, types of cable used, will it need to be in a
> conduit?

The answer: maybe. In reality, if you can find a way to route the cable in an out of the way and reasonably safe location conduit may not be required. But, generally the need to protect the cabling will convince you to route it inside conduit.

> Are there any other issues I need to be aware of besides voltage
> drops when distributing 24vdc power? This will be used in an Industrial
> Automation environment.

Why would you want to do such a thing when you could just as easily run 120Vac out to the remote area and install a cheap 24VDC power supply there.
This might be a much better solution, although 300 feet is not all that far away.

It may also make a difference what you are doing with it on the other end, how much current you will need, etc. perhaps you could give us more
information to work with.
 
Thank you for the fast response! Some additional information is as follows:

-The 24VDC will be used to power field devices and I/O sensors and actuators
-The current consumption will be different and dependent on the amount of I/O at the particular drop but should be anywhere from 1-6 amps.
-the runs will be around 300 feet from the power source to the drop of I/O
-The environment that this will be in is an Industrial Automation environment. Either on a machine or running along conveyors etc.

I hope this helps! Thanks again!
 
R
> -The 24VDC will be used to power field devices and I/O sensors and actuators
> -The current consumption will be different and dependent on the amount of
> I/O at the particular drop but should be anywhere from 1-6 amps.
> -the runs will be around 300 feet from the power source to the drop of I/O
> -The environment that this will be in is an Industrial Automation
> environment. Either on a machine or running along conveyors etc.

Presumably you will also be using it to feed I/O in the field as well.

I'd go with local power supplies. Sounds like you might end up needing a fair amount of 24VDC @ 1-6 Amps per drop. A 20 amp supply might only be
enuff for 3 drops, and would probably require #10 wire be run.

Do yourself a favor and put a local power supply at each drop and just feed 120VAC to each drop.

I see no benefit to running 24VDC all over the place.
 
As i understood from your question the 24vdc will be carried along with I/O. Then it would be a simple idea to install a power supply for 24vdc for desired current at your remote area and short your Remote ground with the source ground
 
300 feet is nothing with 24vdc depending on what you are wanting to power. If you are running cable inside free air you will need to run plenum cable. Outside you could use direct burial if you wanted and put it in the ground without a conduit. Since it is not 120 volts there is no depth code that I am aware of.
 
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