Power and Data in same conduit?

[aptsys]

Wifi is fine if configured properly (WPA2, etc)

Homeplugs similarly are fine if you pick a good one, AES128 is not uncommon:

http://www.ebuyer.com/179960-extra-...line-adapter-twin-pack-pi699e2-4u84-3[/QUOTE]

Trouble is Wifi is also very slow, and decreases exponentially in speed with distance. I'd rather have a gigabit wired connection and an access point in the outhouse if needed.

Homeplugs are the work of the devil.

 

[dormermike]

Homeplugs are the work of the devil.

Why?

 

[imageel]

Ricicle -I hadn't thought of doing it that way around I presume that burying SWA directly improves the heat conduction through direct conduction

aptsys - that was where I was coming from, speed/reception is marginal and made worse by WPA2 and addtionaly by vpn.

Cheers and thanks for your advice
Ed

 

[Paul_C]

Another thing to watch.....

I have an electrician running power using 10mm two core SWA to my shed

Do you know what sort of earthing arrangement he's planning on installing for the shed? There's a tendency to go for an independent TT system for such outbuildings, especially when the house is TN-C-S due to a misconception that "exporting" the earth from a TN-C-S house is not allowed.

You do not want an independent earthing system in the shed if you're running data links between computer equipment in the two different locations. A lot of electricians seem to have absolutely no understanding of such matters.

 

[ban-all-sheds]

The electrician could well not know about the data cables:

I forgot to ask him about the data cabling when he came around to do a survey.

 

[Monkeh]

You do not want an independent earthing system in the shed if you're running data links between computer equipment in the two different locations. A lot of electricians seem to have absolutely no understanding of such matters.

And that's why I favour fibre.

 

[sparkwright]

Don't put the swa in the conduit/duct. Bury it direct in the ground. Run a duct next to it for the network cable, which will ideally be FTP to avoid any interference over that long parallel run.

And leave a spare draw rope or a spare cable for future use.

 

[ccam108]

You do not want an independent earthing system in the shed if you're running data links between computer equipment in the two different locations. A lot of electricians seem to have absolutely no understanding of such matters.

Sound advice, but all Base-T Ethernet ports are isolated by transformers to prevent any nastiness caused by inter-building links.

However, if the Cat-5 is ever to be used for anything else, or if any cores are ever going to be exposed, then what you said should still be headed.

Colin C

 

[slup]

I still want to know why the electrician was going to put SWA in a duct in the first place?

 

[bernardgreen]

I still want to know why the electrician was going to put SWA in a duct in the first place?

Easier to replace in the future, bit more protection ?

Is there any diference between moist ground or water filled duct other than heat dissipation from the cable

 

[bernardgreen]

Sound advice, but all Base-T Ethernet ports are isolated by transformers to prevent any nastiness caused by inter-building links.

However, if the Cat-5 is ever to be used for anything else, or if any cores are ever going to be exposed, then what you said should still be headed

Under BS7671.... are data cables sources of extraneous voltages ? Should they like water and gas pipes be bonded ?

It is not unknown for data cable screens to be carrying earth currents between PCs where the "earth" potentials at the ends are different and the screen has been"earth" at both ends. Some worse case situations have had cables damaged by those earth currents.

 

[JohnW2]

Under BS7671.... are data cables sources of extraneous voltages ? Should they like water and gas pipes be bonded ?

411.3.1.2 ('Protective equipotential bonding') says:

To comply with the requirements of these Regulations it is also necessary to apply equipotential bonding to any metallic sheath of a telecommunications cable. However, the consent of the owner or operator of the cable shall be obtained.

Although 'telecommunications cable' is not defined in the regs, that is presumably aimed primarily at PSN telephone cables etc. and WAN cables which span two or more properties - and that makes sense.

If a communications/data cable exists wholly within the equipotential zone of an electrical installation the sheath of that cable is not really 'liable to introduce a potential' per the BS7671 definition of 'extraneous-conductive-part', so there is no rational reason (and probably no requirement under the regs) for requiring bonding. Indeed, any 'earthing' of its screen will effectively be 'bonding' to the installation's CPC network - although probably not with a 10mm² MPB conductor!

Kind Regards, John.

 

[ccam108]

Sound advice, but all Base-T Ethernet ports are isolated by transformers to prevent any nastiness caused by inter-building links.

However, if the Cat-5 is ever to be used for anything else, or if any cores are ever going to be exposed, then what you said should still be headed

Under BS7671.... are data cables sources of extraneous voltages ? Should they like water and gas pipes be bonded ?

It is not unknown for data cable screens to be carrying earth currents between PCs where the "earth" potentials at the ends are different and the screen has been"earth" at both ends. Some worse case situations have had cables damaged by those earth currents.

Not an issue for UTP cable, which is more than adequate in this situation and is used in 99% of Ethernet installations.

Back to the original question, taking a risk/benefit approach to having the cables in the same duct:

Risk: The SWA could somehow get damaged, a live core could avoid touching the armour and make contact with an exposed core of the Cat 5 that has been damaged in the same place. Minimal chance?

Benefit: Depending on the run, the convenience of not needing another duct, the ability to draw additional cables.

I'm not an electrician so I'm not going to post conclusions but you can draw your own.

 

[JohnW2]

Back to the original question, taking a risk/benefit approach to having the cables in the same duct:
Risk: The SWA could somehow get damaged, a live core could avoid touching the armour and make contact with an exposed core of the Cat 5 that has been damaged in the same place. Minimal chance?
Benefit: Depending on the run, the convenience of not needing another duct, the ability to draw additional cables.
I'm not an electrician so I'm not going to post conclusions but you can draw your own.

I personally agree totally with the conclusions you are not posting. As I wrote before, I regard the BS7671 requirement for 'separation' to be one of it's more daft/ridiculous requirements, and I'm sure I'm not alone. I am not frightened to admit that I have SWA and ELV ('signal'/'control') cables in the same underground duct, and I loose absolutely no sleep over that! As far as I am concerned, the benefits more than compensate for the ludicrously small 'risks'.

Kind Regards, John.

 

[bernardgreen]

It is probably only in a fire situation where insulation melts before the metal conductors melt that the safety of people using data equipment would be compromised by data cables in the same duct as power cables.

Fire in a small underground duct is un-likely. In larger ducts it is a possibility that has to be considered.

One small risk in a small duct is if chemicals get into the duct and damage insulation, some garden chemicals can rot PVC ( cannot remember which ).