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What is a recommended distance between parallel runs of mains and network cabling in chased blockwork


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Working on cabling layout now.

 

When running 240VAC and Cat6 data cabling down from ceiling void to a shared wall socket, I'm assuming putting both in same channel is not best practice.  

 

So my question is: what is a sensible separation between parallel runs of mains and data cables?

 

2cm, 5cm, 10cm? Closer in blockwork than behind plaster board? Or am I being too picky about this?!

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I doubt it will be a problem for the functionality of the CAT6 cable (assuming you aren't going to use them for anything really sensitive like long runs of 10Gb). In theory power cables can introduce interference but I'd be surprised if it caused a problem unless you twisted long runs together or something like that. Using shielded cables would make this even less likely...

 

However its probably just good practice not to run high voltage and low voltage cables together? Someone with more expertise than me will probably be able to comment on that...

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I've run literally thousands of M's of Cat 5 in my time and never really had the time, or encouragement from my employer, to worry about keeping X distance from bunches and bunches of mains cables. Everything still worked fine ( last solicitors office I did we fitted 40 odd PC network points and around 60 phones ) and I shudder to think what was behind some of the false ceilings that we blindly pulled the runs through ( with 10M long glass-fibre rods ). All I can tell you, without exaggeration, is that it all worked 100% perfectly and is still working there today. 

Im not saying do a bad job, and in not saying be lazy, but don't exceed the requirements beyond a practicable point as that's just wasted time and effort and it can be better spent elsewhere where it would be recouped measurably. ;)

Are you having to chase out for these cable drops? 

 

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Shielded CAT5 is pretty immune to most things apart from HF interference from some dimmer switches and older fluorescent light fittings - other than that it's the usual stuff about keeping high and low voltage cables apart and like Nick says I've seen it run parallel i.e. 50mm apart with no problem. Just run a wide chase with two cover shields  

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By the book (the OSG anyway) it's 50mm away from "telecommunication wiring" unless the lv cable (<600v a.c) is in:

1) conduit

2) trunking 

 

Either of which if metallic must be EARTHED or

 

3) if it's run in MICC (Pyro)

 

I think the statement on this is very ambiguous personally. Read the exact wording and imo it clearly says the 50mm can be ignored if the above conditions are met.....so PLASTIC trunking etc is fine. Plastic will certainly add to the insulation between cables but it's odd when the main reason for separation is to prevent the "mains" inducing potentially dangerous  voltages in the telecom stuff run parallel to it by induction.

 

This all harks back to old phone line type stuff that wasn't shielded. 

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