Do alarm systems require a local 3A fuse?

[StagsHeadNo.4]

I have recently carried out a Periodic Inspection and noticed that the alarm system is wired straight from the fuse board on a 6Amp MCB. I normally see alarm systems with an unswitched 3A fused spur local to the alarm. Is this a 'manufactors instructions' debate or is there a regulation about this? Thanks for reading.

 

[steamboatwilly]

Can't think why it would be a problem if it's the only item on that circuit? Having said that, every alarm I've seen also had a local unswitched fuse.

 

[iansparks]

I seem to remember it is in all the Alarm manufacturers Installation (not gospel) Also for Door access systems, Also it cant help comply with local Isolation

 

[Lou7]

mcb can be used for isolation.

 

[oldtimer]

All alarm systems require a point of electrical isolation via a 3 amp unswitched fused spur. They should be treated as a fixed appliance hence the need for a point of isolation. Why unswitched because the BS states that the mains to the panel should be tamper proof by joe public. Also in the past an alarm system would be rented so hence the company could take their equipment away and leave a safe power supply behind.

I been working with intruder alarms for the past 26 years and I have seen some humdingers as they say in Scotland ie 1mm wired straight in to the live side of the 100 amp isolator switch on a CU

 

[2391bob]

Also,a local means of isolation means it`s easier to do your I.R tests.You also need to disconnect the neutral at the fcu.

 

[steamboatwilly]

I been working with intruder alarms for the past 26 years and I have seen some humdingers as they say in Scotland ie 1mm wired straight in to the live side of the 100 amp isolator switch on a CU

Whoah....crikey! Amazing what some people do.

My 'best' - so far - is a double socket in a kitchen which was not only turned through 90 degrees but was wired into the switch wire on the kitchen light. Not a problem if you wanted a <6amp item running only when the light was on.

 

[2391bob]

Whoah....crikey! Amazing what some people do.

My 'best' - so far - is a double socket in a kitchen which was not only turned through 90 degrees but was wired into the switch wire on the kitchen light. Not a problem if you wanted a <6amp item running only when the light was on.

What a ********,should have put it on the common;-)

 

[steamboatwilly]

What a ********,should have put it on the common;-)

Yup!

 

[StagsHeadNo.4]

I have also been told it's to protect the appliance under fault conditions. (How true this is i'm not sure.) But apparantly the 3A fuse would prevent any damage to the alarm if a fault was to happen? Is this bollox? Wouldn't the 6A MCB do just as good a job?

 

[oldtimer]

Guys there is no big deal when it comes to fix appliancies they all have to have a point of isolation and the protection to be rated as per the manufacturers advice. In the old days you would have to run a 2.5mm cable to supply the switched or unswitched spur as the mentality at the time was the fixed appliance could be removed ie alarm panel and a socket put in its place. I have seen some houses that the 5 amp round pin sockets frontplates were removed and replaced with 13amp sockets the only problem was that the 5 amp sockets were spurred off the lighting circuit so to get round this joe public simply upped the fuse rating from 5 amp to 15amp or for a bit of silver paper from a smoke packet (no joke I have seen this)

So what do I rate as a fixed appliance. ?

intruder alarm panel unswitched spur
fire panel unswitched spur
door entry system unswitched spur
230v smoke heads switched spur
central heating system switched spur
fixed wall heater switched spur