Running alarm cable with mains cable/lighting etc

[Guest roonster]

Hi,

My friend ran some wiring in my house for an alarm system which is later to be connected by a tradesmen.

However Ive been reading around and people have been saying that alarm cable should not be run alongside mains/lighting cables.

However having just lifted up a few floor boards ive noticed that the alarm cable has been run alongside mains and lighting wiring.

Is this likely to cause a big problem and if so whats the fix? Re-run all cabling?

Thank you.

[secboy]

It can be a problem! and any one in the trade will say its a definate no no to run in parallel with mains due to induced emf(the AC induces a voltage into the cores of the alarm cable)the way to avoid any possible induced emf is to run no closer than 100mmm in parallel but with some segregated plastic trunking the low voltage section is only devided from the high voltage section by a few mm of plastic yet its assumed to be ok! If you can move them apart without much of a problem then i would do it if not and you experiance faults with no known cause then you will be fairly certain that the cabling is the cause hope thats of some help?Paul(Always available for polite assistance with no bad language)

[Deltaseven]

It is never a good idea to run your alarm cable alongside mains cable, as Secboy says, you can get Induced A/C, which can cause all sorts of problems, from false activations to data corruption on the keypad.

The extent of the problem will vary depending on what else you are installing. Are the cable runs very long, or are there many? The more cable there is the greater the opportunity to pick up A/C.

What panel are you installing - some are more succeptible to A/C faults than others.

[Adi]

I

[Guest roonster]

Thanks for your reply guys.

He is going to be installing the Scantronic 9800+ with exapander as i have alot of zones.

All the alarm cable from upstairs meets together as it heads down some concealment boxes along with the ligthing cables. (5 in total)

Id says the run for weach was about 10 meters or so.

Also some of the cables run through the floorboards where there is the ring main wires supplying the upstairs sockets etc.

[Adi]

How do i edit my spelling mistakes.

[bellman]

Done it for you Adi,

But for future reference just click the edit button at the bottom right of your post.

Regards

Bellman

[breff]

Ill probably get moaned at for this but on a domestic i shouldnt worry to much about it, i agree its best practice to keep it segregated(need a dictionary) but on short runs it wont hurt. I seen technical write up somewhere a while ago and it mentioed you needed runs of 30 metres plus to give a significant amount of induced ac/emf and obviously the amps in the supply the greater it is.

63935[/snapback]

Ive had 95v ac induced on a domestic Adi, having said that , an ACT1313 dumped the lot.

Check out www.actmeters.co.uk , in particular the ACT1313 filter ,it will get rid of any induced AC.

Is there no way the alarm cable could be moved to the opposite joist where it runs with mains?

[Adi]

Ive got a couple of them in stock. Ill keep me trap shut in future.

[Guest roonster]

Ive had 95v ac induced on a domestic Adi, having said that , an ACT1313 dumped the lot.

Check out www.actmeters.co.uk , in particular the ACT1313 filter ,it will get rid of any induced AC.

Is there no way the alarm cable could be moved to the opposite joist where it runs with mains?

63965[/snapback]

No unfortunately theres no way to move the cables now. Theyve been run the whole distance and through holes in the joists so i guess it cant be done unless he re-runs all of them, which will be difficult now as decorating etc has been done.

I guess if we go ahead and install it and see what happens. If faults occur we buy the filter?