PIR- Alarm wiring inside consumer unit

[ProDave]

PIR today. Fairly modern house, all okay except the alarm wiring.

The alarm panel is on the wall immediately above the consumer unit.

All the alarm sensor cables exit from the wall inside the consumer unit, then pass through the consumer unit, out through the top of it into the alarm panel.

I want to code it as 4 (manly because I don't want the job of rewiring the whole alarm panel, there must be about 30 alarm cables)

The alarm cables don't actually touch any of the wiring within the CU, which is why i'm of the opinion it's not dangerous and therefore only a non compliance. also the alarm cables enter the CU through a knock out of their own, so again not touching any electric cables.

Your thoughts please.

 

[alchemist]

I think you're right.

Suppose that's a no-no because of not segregating band 1 and 2 circuits, but not a safety issue.

 

[Doc Hudson]

Not the best working practice by the sounds of it. Isn't this is the same problem as data & power in stuff like dado trunking? Maybe some additional protection could be put over the alarm cables, modify a piece of plastic trunking or flexible conduit possibly?

Doc H.

 

[ProDave]

Perhaps therefore it's not even serious enough to mention?

Yes I was thinking segregation. I'll bet there's also no segregation where the cables run together in the walls, but I can't prove or disprove that so no comment.

Dado trunking designed for the job has a separate compartment for mains and data cables.

 

[PaulSC]

Dave,

Obviously band 1 and band 2 should not be within the same enclosure as stated (528.1 - p61 OSG), though they do allow 5 exceptions. Yes, you could throw in a bit of MT if there's room.

I though an easier solution would be to simply prove the cables are insulated to the highest voltage present, though 30 minutes browsing the net has proved me wrong!

 

[alchemist]

I think as well as insulation it's also about interference from induced EMF, which will be present in the CU because the conductors are separated for termination - so although they normally cancel out in twin cables, they won't in the CU.

if you wanted to shield the alarm cables you'd need something that could protect against an EMF (does such a think exist for cabling?)

 

[kme]

+1 to alchemist - there are indeed 2 seperate issues here:

1. Induced voltage into the alarm cabling (detrimental, and believe it falls foul of NACOSS regs)....though BRB now includes EM interference limitation, iirc; which would make it a code 4 for that (if I`m right.)

2. PaulSC`s comment regarding voltage bands. The alarm cable isn`t likely to be rated at 230V; therefore shouldn`t be sharing the enclosure, ref: 528.1 et al. I`d probably want to give it a 3 - perhaps investigation into the rating of the alarm cable needs to be undertaken?? Don`t think it warrants a 2; but definitely needs to be noted, IMO.

KME

 

[batty]

Typical alarm companys I keep my cables seperate then they come along and put them through my holes just to save them drilling there own. I pointed this out on a job and the boss said we will put voltage suppressors on our cables. They really make me laugh with there attitude.

 

[Evans Electric]

Although in reality I don't suppose anything would happen but as far as I'm concerned this is a big no-no . If you fitted a dinrail doorbell tranny in a consumer , the bell wire would have to be insulated to 240v . Its a disgrace really . If you show it to a scam assessor they'd have a heart attack .