Mains Supply to Intruder Alarm

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Sorry Breezer :(

I've been on one big almighty horse all day....
For what it's worth, here's my thinking:

I always try and fit a dedicated circuit and put it on the non-protected side of the cu so it doesn't go off if the rcd trips.

i can see in this install, it is not feasible.

BA companies like to fit it to the lighting circuit because (for some reason) the teaching is to use the smallest denomination mcb/fuse.

But I think it is short sighted using the lighting because in my experience as a pro spark, the lighting is the circuit most likely to fail.

I would spur off a ring, using an unswitched spur with a 2 (or max 3 Amp fuse. ADE recommend 2A.

Most panels draw a max of 1A anyway so this is no problem.

Don't forget, to comply with the almost outmoded BS4737, the back-up battery must keep the panel up & running in the event of a power failure for at least 8 hours.

I have seen allsorts in my trade (which covers the NW), including so called reputable nacoss firms fitting crappy electrical supplies to panels.

The worst of these was in Manchester, where I found a highly respected firm having fitted a fused spur (13A) with flex (NO!!!!) and it was wired directly to the main tails in a n old Wylex board with a wooden back. Instead of letting the flex into the box, they had just screwed the cover back on, flattening the flex in the process. Unbelievable!
Anyhow chaps

You don't need a fused spur for an extractor. If the circuit is rated at 6A or below, there is no need for a local fuse. Just tap off the lighting circuit. You still need some form of switching, though.
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I think that I started quite a debate here - I didn't expect two pages on the topic :eek:

I think that it is quite right that alarm companies do the easiest thing to suit the situation. I have seen an alarm panel direct onto the lighting circuit WITHOUT a fuse connection which I thought was even worse and one on an extension lead from the hall socket via a 13A plug!

Curiously I posted a similar question on a secuirty alarm website and get a similar answer to this forum - use a direct feed from the CU or spur from the ring. They then go on to mention 16th Edition and NICEIC inspections for work done. They can't all be bad.

On the advice of the forum and having talked to my father (retired electrical contracting manager), I will break into the ring circuit (hopefully enough slack) and fit a fused connection in the ring for the bell transformer and then a spur for the alarm panel.

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