Ethernet/Power SWA cables - can they share space ??

[buzzer123]

Hello all...….
I would appreciate some advice please as there is lots of conflicting opinions on the interenet.

I wondered if anyone new the actual UK rules and regs or sensibilities with regards to ethernet installation alongside power cables in a trench ( I appreciate the whole high voltage / low voltage divide and that different types of power emit noisy interference that can disrupt ethernet signals and I have even read of fire risk and illegal in France etc etc.)

The 7a ethernet being installed in this situation is shielded and I understand that ethernet should not be in the same duct as a swa power lead but if it was separated by a layer of sand in a trench would that be acceptable or would it need a separate trench to avoid ethernet interference – (the ditches could be deep with 450mm of sand separation between the power and ethernet cables before concrete upfill to surface over trackway areas - please advise.)

As a thought could you also apply a secondary shield to the ethernet cable as the last 2 metres into the service room is ducted ( the router location for the internet and fuse board) and it would make my life easier if power and ethernet shared the duct?!? - maybe place the ethernet into another smaller duct…..mini duct for ethernet within power flexi duct – any ideas?

If this is a definite no no I can install the ethernet into the room through a separately drilled access hole and dig seperate ditches for it but this increases work load significantly...…..and I would rather dig one really deep ditch for each of the swa power/ethernet locations and utilise a heavy sand separator for the cables - would this be sufficient ?

Look forward to receiving some advice

Thank you in advance for your help with this.

 

[Strima]

I might be corrected on this but SWA has a basic form of shielding which will reduce EMF and the shielding surging the Ethernet will reduce this further.

Current load is also a factor, the more current drawn the greater the EMF. What sort and type of load are you expecting to be applied to the power circuit?

Good separation, over 50mm, will also help. One of the main reasons we don’t normally run power and data next to each other, apart from EMF, is the risk of a fault causing damage to the data cables. This is where’s the insulation of the cable must be rated to the highest voltage.

If you could explain more about the nature of the circuit, it’s intended use, length of run, expected load, type of ground etc we would more than likely be able to advise.

 

[James]

Have you considered running fibre instead?

 

[buzzer123]

Hi Strima,
Thank you for your responce - appreciated

Max

load on site -100 amp three phase (unlikely to ever pull this amount however) - type of ground heavy clay​

Power a farmhouse with its electric gate entrance - a 2x farm workshops (lots of heavy drawing power tools - welders - plasma cutters etc) and several other small power drawing out buildings (lights only etc with minor power needs)

length of run

Grp kiosk down to fuse board (260metres powered by 150mm 4 core armoured with a separate 70 mm earth)

These two cables in share the duct up out of the trench into the service room where the fuse board is located with two other cables - one 50mm 5 core armoured out and over to the farmhouse approx 60metres distance from fuse board (farmhouse location will require ethernet) and a 25mm 3 core - 70 metres distance to electric gate (electric gate location will require ethernet)

So my question is can 2 seperate ethernet cables share this busy access duct up into the service room with these armoured cables and any ideas how to further armour the ethernet to enhance its performance if this idea is viable ?? or should I safe guard ethernet cable and keep it well away and access the service room up to the router via a separate location away from the power duct in ?

And if a separate access for the ethernet is the only sensible solution...……. can the ethernet share trench space with the individual power cables discussed and if so please advise for guarding purposes how much sand separation should be applied between them.

The two farm workshops both require ethernet and they share a separate duct out of the service room and will be serviced each by 50mm 5 core armoured cable and outbuildings again have another duct etc etc...……. but once I have the answer to the above I guess I can supply the same logic to these...……

(James the spark - ethernet cable is already purchased - fibre was considered but ruled out due to cost and the fact that all applications on site are ethernet ready - but thankyou for your input)

Thank you again for all your advise with regards to this question...……...

 

[plugsandsparks]

I have a similar install but outside of ethernet distance so have used fibre. Not expensive at all, about £200 per run. I would not consider using the same duct as such heavy cables, ethernet is a bit delicate for direct burial. If its too late to pop a second duct in the same trench then fibre makes more sense to me

 

[Strima]

You can chuck as many data cables together as you want with no adverse effects under normal operation. If you can make your trench a little wider for separation if not back-fill the power by 100mm then add data then fill to required level.

I'd personally run some 50mm duct for the data with a draw rope so further cables can be run in if required.

Fibre may cost slightly more and a couple of media converters will add to the cost but the data speeds and longevity of the cable are a big plus.

 

[buzzer123]

Thank you both - so fibre could share same ducts into service room alongside the power cables but not ethernet?

 

[plugsandsparks]

The fibre cable is still vulnerable to damage when sharing a duct with big heavy power cables, so generally avoid if possible. The signals in the fibre cannot be interfered with by noise from the power cable as the signals are pulsating light rather than 500Mhx radio type signals for typical ethernet over cat5,6,7. The fibre cable should not have a metallic element in its construction so again no risk of induced 230V from the power cable. Its still a compromise over separate ducts but one where in some circumstances you can live with. At the end of the fibre you connect a converter that takes your ethernet RJ45 and converts to the appropriate fibre port. You need room for these convertors and some power to power them.

 

[buzzer123]

Thank you both - really appreciate the advise. I have already purchased the ethernet 7a - imported from Germany with a really heavy duty armour so I will access the service room in a separate location and then intercept corresponding trenches and bury them in proximity to the power cables but with a good separation of sand (probably as advised in a 50mm duct with pull cord to future proof) Cool - A plan has been made. have a good day all

 

[lennspark]

Thank you both - really appreciate the advise. I have already purchased the ethernet 7a - imported from Germany with a really heavy duty armour so I will access the service room in a separate location and then intercept corresponding trenches and bury them in proximity to the power cables but with a good separation of sand (probably as advised in a 50mm duct with pull cord to future proof) Cool - A plan has been made. have a good day all

Doncaster cables do SWA with integrated data cable for EV charging points, Check out the Efixx YouTube Chanel that the guys visit the factory.

 

[buzzer123]

Thank you all for your advise re the ethernet cables in relation to power cables which could detract from the quality of the ethernet due to interference from noisy electric cables………..

I think I may have solved the issue for the ethernet entering the service room by using another existing duct that I had overlooked………….

However I still have two minor unanswered questions to which I would appreciate further guidance–

• How far can interference from noisy power cables travel….i.e.: how far does the ethernet cable have to be away from an existing power cable for the ethernet cable to maintain 100% performance – I ask this as in one location the ethernet cable will enter an underground service manhole that measures 1.2m x 800mm. A power cable also enters the same manhole but through a separate concreted duct. The ethernet and the power cable exit the manhole via separate concrete encased ducts but the question is would the swa power cable fill the entire manhole with noisy interference or does the interference remain isolated to a small localised area around the cable (like a halo) – if this is the case I can just keep the power and the ethernet cable separated within the manhole
  
• From a ducting standpoint to insulate the ethernet from power interferance can you recommend any brands of ducts that offer protective qualities that shield the ethernet better than others (Im sure that not all ducts are equal )

Thank in advance for your opinions on this…………………….