Appropriate power feed for burglar alarm

[Taylortwocities]

WHERE in that sentence did I say mention lighting circuit……?

You didn’t, but the OP did. IF Winston sees FCU and lighting circuit on the same day he panics and reels out the usual untruths.
Predictable and rather sad. I hope his carer tucks him in at night.

 

[JohnW2]

I have my alarm system connected to the lighting circuit via an FCU and I also have a security light on the back of the house fed from the lighting circuit via an FCU.

You have two unnecessary FCUs then.

He does - but one practical issue you seem to overlook is that people quite often 'unnecessarily' use an FCU because they are generally cheaper than DP switches.

 

[sparkymarka]

I guess the use of the fuse spur stems from alarm panels in the eighties that didn’t have a internal fuse between the supply and the transformer , most panels have a fuse at the incoming supply ( Scantronic 9448 plus and pyronix enforcer being an exception)

 

[JohnW2]

I guess the use of the fuse spur stems from alarm panels in the eighties that didn’t have a internal fuse between the supply and the transformer , most panels have a fuse at the incoming supply ( Scantronic 9448 plus and pyronix enforcer being an exception)

Yes, but one of the few valid points winston makes is that the 'usual' 3A fuse put into a FCU used for such a purpose will not discriminate from a 6A MCBB protecting the circuit (assuming a lighting one) - in other words, even if the alarm panel 'needs' external over-current protection (which it really should not rely on), then a 3A fuse would probably not achieve that any more than would the 6A MCB already there. If one put a 1A fuse in the FCU, that would be a bit better - but few people seem to do that.

However, as said, fuses in plugs and FCUs, or MCBs/RCBOs in CUs are really their to protect cables, not equipment is connected to them (which, if it needs it, should have internal protection)

Kind Regards, John

 

[winston1]

He does - but one practical issue you seem to overlook is that people quite often 'unnecessarily' use an FCU because they are generally cheaper than DP switches.

Price should not come into it. Good practice does.

 

[winston1]

It is. But a plug and socket is NOT what is REQUIRED by the companies that install and maintain burglar alarm systems. Why can you not understand that?
It’s so somebody’s wife doesn’t unplug the alarm system and plug in the vacuum cleaner. Also so the engineer knows.…

They should say so then.
Vacuum cleaners these days don’t have unfused connection units on them, they have 13a FUSED plugs so your argument is wrong.

 

[sparkymarka]

Yes, but one of the few valid points winston makes is that the 'usual' 3A fuse put into a FCU used for such a purpose will not discriminate from a 6A MCBB protecting the circuit (assuming a lighting one) - in other words, even if the alarm panel 'needs' external over-current protection (which it really should not rely on), then a 3A fuse would probably not achieve that any more than would the 6A MCB already there. If one put a 1A fuse in the FCU, that would be a bit better - but few people seem to do that.

However, as said, fuses in plugs and FCUs, or MCBs/RCBOs in CUs are really their to protect cables, not equipment is connected to them (which, if it needs it, should have internal protection)

Kind Regards, John

That may not work in all cases as the Texecom premier panels have a 3amp fuse in the internal fuse block due to the switch mode psu taking more than 1amp when powering up ….

 

[winston1]

Winston1

The requirement is :-

(1) a means for the alarm service technician to be able to ensure the mains is disconnected from the panel
(2) a means to ensure the alarm cannot be turned off by accident.

(1) he uses a tool to disconnect the cable inside the connection unit.
(2) there is no switch that can be switched OFF.

EDIT correction of my error about connection unit being fused

So is there a standard unfused connection unit for this or does the alarm technician carry a pocket full of tools hoping he has the right one.

 

[bernardgreen]

They should say so then.

but would you believe / trust them, you often say that the manufacturers get it wrong,

 

[bernardgreen]

or does the alarm technician carry a pocket full of tools hoping he has the right one.

it just needs a screw driver......

 

[sparkymarka]

So is there a standard unfused connection unit for this or does the alarm technician carry a pocket full of tools hoping he has the right one.

Again …..where are getting unfused from ?

 

[Taylortwocities]

He’s confused again (pun intended). He’s so busy trying to be unhelpful. I think he/she means unswitched.
But congratulations to @winston1 you have, yet again, effectively killed another thread with your innane and pointless posts.

 

[JohnW2]

That may not work in all cases as the Texecom premier panels have a 3amp fuse in the internal fuse block due to the switch mode psu taking more than 1amp when powering up ….

What may not work - do you mean using a 1A fuse in the FCU?

If what the panel needs, and has internal, is a 3A fuse, then that's an even greater reason for not having yet another 3A fuse in a FCU feeding it!

In any event, even the 'internal' 3A fuse might well be pretty redundant if it's on a lighting circuit, since a B6 MCB would be pretty likely to trip before such a fuse blew.

Kind Regards, John

 

[JohnW2]

He’s so busy trying to be unhelpful. I think he/she means unswitched.

Indeed. I know he has problems, but I doubt that even he recognises the concept of an "unfused FCU"

Kind Regards, John

 

[winston1]

Again …..where are getting unfused from ?

From this post by Taylortwocities:

The requirement of the BA companies is an unfused connection unit adjacent to the panel.