I am busy finalising planning for the installation of my first solar system, and intend to make use of SolarAssistant. For several reasons (which we do not need to get into) I would prefer to run CAT6 ethernet cable from the SA Raspberry Pi to my router, and I have seen several people on this forum suggest it (e.g. in this thread).
Originally I had planned to route the CAT6 into the ceiling through the same trunking as the cables to/from the inverter, however over the weekend I came across a blog post and accompanying YouTube video saying that this is a very bad idea, since the electrical cables generate an electrical field (EMI/EFI), which can cause data loss or corruption, as well as inducing heat in the network cable (possible fire risk).

I would therefore like to hear from anyone who has actual experience using ethernet cable in this way, and what precautions you took to mitigate or eliminate these issues.

You can use shielded Ethernet cable (recommend linkbasic outdoor shielded cable, they sell rolls or even flyleads - google it) and it shouldn't get affected by the power cables next to it. Just the one cable for solar assistant, I wouldn't stress. 

If you worried, put it in some sprague. 

Edited October 10, 20241 yr by abd7

I forgot to add that I had enquired from SolarAssistant about this, and they concurred that running ethernet cable next to power cables would be a bad idea.
The support agent also stated 

Quote

The common standard for this is to have separate trunking for communication/ethernet cables but this is not always feasible. You do get outdoors grade ethernet cable that you can run along the outside of the trunking, but this is shielded and higher grade so it can get expensive over distances.

 

7 hours ago, phl003 said:

I forgot to add that I had enquired from SolarAssistant about this, and they concurred that running ethernet cable next to power cables would be a bad idea.

Ethernet is twisted pair cabling which is fairly resistant to interference since its differential voltages applied to the pairs, in other words, the voltage difference between the 2 wires making up a pair make up a signal, if external influence induces a voltage on this pair, both wires if the pair would have their voltages lifted or lowered by the same amount, which means the pairs signal should remain intact... temperature, if your cables really get hot, then they are likely undersized and you should consider replacing them with larger diameter cables.

Depending on the length of the ethernet run and whether its in a location where lightning may be an issue, I would consider going fibre. In your case it would mean you need to add a small switch that can take a SFP+ module or a media converter, which just takes a SFP+ module and has a normal ethernet port out and on the other side of the fibre link, you hopefully have a switch that can take a SFP+ module, else same scenario, depending on the distance of the ethernet run, fibre can work out cheaper and if lightning is an issue, infinitely safer.

Edited October 11, 20241 yr by Kalahari Meerkat

As mentioned already, shielded cable is your best bet to reduce interference when running ethernet cable close to other cables. Note however that there are several different types of shielding: https://www.truecable.com/blogs/cable-academy/ethernet-cable-shielding-types

So do not just search for "shielded" cable, also check the shielded cable type.  Also note that shielded cable should be properly grounded, use shielded (metal) connectors to terminate the cables. 

That blog post is giving you excellent advice. You should never run standard Ethernet cable in the same conduit as AC power cables, especially from a solar inverter. The high-amperage DC and AC power will generate significant electromagnetic interference (EMI), which will severely degrade or completely kill your data signal.

The correct ways to run the cable are:

1. Use shielded Ethernet cable (F/UTP or S/FTP) and ground the shield at one end.

2. Run the data cable in a separate conduit, keeping at least 12-18 inches of separation from the power cables.

3. If they must cross, make sure they do so at a 90-degree angle to minimize interference.

For a reliable, code-compliant installation, keeping the data and power runs separate is the most important rule.

https://www.datatelaz.com/

Sorry to butt in like this, but the Topic of this Thread is somewhat misleading (for my ADHD !).

In my vocabulary, SOLAR POWER CABLES typically = PV , so SOLAR Cables are DC, thus no Changing EMF, as per AC counterpart. Feel free to correct me if DC EMF is a thing, also learning!

So it would be OK in my book to run Ethernet next to your Solar Cables.

As per replies, NOT OK to run Ethernet next to any AC cables, not for long distances, else use metal Spragg.

If you have to, due to conduit shortage, then use STP cable to minimise possible interference.

58 minutes ago, Sidewinder said:

So it would be OK in my book to run Ethernet next to your Solar Cables.

I agree with your above statement. DC produces static electric and magnetic fields (not changing EMF), so it won’t induce currents or data interference in neighboring signal cables. Big no no near AC cables.

Edited October 31, 2025Oct 31 by TaliaB

49 minutes ago, TaliaB said:

DC produces static electric

They don't make DC like they used to. I am pretty sure MPPTs and battery inputs have a bit of switching in them... In the 100 kHz range?

Interesting, and important, discussion - thanks to @phl003 for starting this.

I had a relevant experience with data cables picking up interference a few months ago. My installer placed the battery communication cable in the same trunking as the earth wire, and for a year everything worked quite normal, but then the inverter started reporting BMS communication errors.

Turns out my ham radio enthusiast neighbour bought a new transmitter, hooked up to a huge antenna in his back yard (looks like a mini cellphone tower...), and we think this induced a signal on the earth wire (which is after all a huge antenna spread out all over the house...) After I moved the signal cable away from the earth wire, and having the firmware of both the batteries and the inverter updated, the problem went away - though I cannot say for sure if it was the moving away of the signal cable or the update, perhaps a combination of both...

Hey guys, I have run my Cat6 ethernet cable in the same trunking as all of the solar system cables. Zero issues in the 2yrs since. The Pi itself is sitting on/against the 50mm battery cable within the trunking.

Again, Zero issues in 2yrs.

It sits within the green rectangle space...surrounded by DC and AC wiring and earthing cable.

Edited October 31, 2025Oct 31 by Carl Anthony

12 hours ago, Carl Anthony said:

Hey guys, I have run my Cat6 ethernet cable in the same trunking as all of the solar system cables. Zero issues in the 2yrs since

Good quality twisted pair ethernet cable normally has sufficient shielding 👍

An Observation , with much discussion regarding ethernet and power cables, . depending on your local electrical code, data should always be in a separate conduit to ac power cables...... however , one can purchase cables for ev charge points which contain 6mm ac conductors and a screened cat5E cable in one sheath!! available in the UK ! EV Power + Data Cable - FS Cables