Alarm Cables Running Parallel With Mains Cables

[Cubit]

Wireless not an option?

To stop interferrence by induction from mains, separation should be 18" for anything over a yard (in old money). If required you sholud cross a right angles

Mixing low voltage and mains cables in the same trunking through hole, access hole etc is forbidden under building regs, but if clipped along an open beam I'm not sure if this restriction still applies.

Interference issues aside, you can (i think) run a separation trunking or conduit in a riser where mains exists. iirc it has to offer the same level of mechanical insulation for both cables, more than concidering the different voltage potentials. That's why for instance 3 channel dado trunking is 'allowed' to carry comms and mains alongside but in different compartments.

If using screen cable, someone should advise if both ends or if one end, which is grounded.

Arfur

18" ??

A purely arbitrary figure i assume? just edging on the side of caution?

Unscreened and with no physical metal separation barriers the recommendation is 200mm

With screened cable this drops to 50mm

That said, chances of induced spikes/glitches are normally extremely minimal.

For the couple of quid extra just as easy to use screened.

[arfur mo]

Based on 18" separation. I'd settle for that.

There is decorative trunking available from likes of TLC, comes in all colours and semi circular in profile, might be another aesthetic option.

I don't know how touchy this panel is about induced RFI, but I figure data, telephone and alarm cables are often run for long lengths and close to mains within 3 compartment dado trunking, with no problems.

Just before i'm shot at, ever seen the pics of telephone wiring in India?

To me, while I observe them where practical, it sort of makes a bit of a nonsense about the separation recommendations, as the dado trunking is not screened in any way, contravenes the spacing rules, yet where used I have not had any problems.

Your call, but I'd likely give it a go, use screen would be prudent advice, and just clip sparingly to test 1st. if it seems ok then clip properly.

Interference is a saucy issue, if that cable feeds a fridge, and the suppression is shot this can cause spurious issues, as the motor switches.

Arfur

[Cubit]

I was 'admiring' the cabling on a Galaxy install today. Tywrapped to Armoured, T&E, piping, you name it, the lot. Unscreened cable too. Works fine.

[arfur mo]

Some stuff out there lol!

Driving through camberwell on rhe south circular, on the left about 200 yards before that massive junction going westbound, in traffic I spot an external siren attached to the side of an estate agents facede. The place is very loudly coloured in green and yellow so easy to spot, possibly why i looked as you do when bored.

thing was, it was on what was a window that had been boarded over, nought to odd about that you might say, but this was a very hot day, and somone had oppenned this 'window' outeards so now the siren was tilting forward at about 35 degrees.

Just when i though I'd seen most everything, do I love this trade? .

Could not get pic at the time, as spotted just when moving off, but will if passing that way again

Arfur

[astro]

Hi Guys,

Screened it's gonna be as there are few if any routes where I can run cables without them being a tad close to mains wiring, but as mentioned, I'll try and keep them as far apart as possible. I'll also take on board the fridge/freezer motor issues as well.

Once again, many thanks for all your help.

Graham

[Guest Oxo]

Glad we can assist.

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[james.wilson]

yep thanks for the follow up, let us know how you get on, and how much ac is induced on the cables in the end.