Does this cable need an FCU?

[NewOrder]

I am hoping to finally to get round to replacing the alarm later this week. I have decided on a wired one now due to cost. The existing control box is in the hall but I want to move it to the electricity cupboard and use a remote keypad.

There is a 1.0mm flex cable coming from the consumer unit to the hall to power the box but I am simply going to cut the wire and use it to power it in the cuboard. It is wired into the downstairs lighting circuit as is a 5 or 6 amp fuse on the CU (can't remember it is a while since I checked).

Does this cable need to be connected to a fused connection unit between the CU and the alarm control panel? Part of me thinks not because the 5 amp fuse in the CU should protect the cable and there is a (probably 2 amp) fuse in the control panel to protect any alarm faults.

Am I right in thinking I would only need to use a FCU if I was taking a spur of the ring main?

Also I am getting a spark in to rewire the ringmain and check the electrics later this year, I assume he won't care less about the alarm other than checking its mains supply?

Finally in terms of the legalities of it (which the spark will sort when he replaces the CU anyway) I assume as the cable is already in place (the alarm cable was put in 1990) I don't need to worry about Part P and certs etc?

 

[securespark]

Regardless of whether you use a fused spur or which circuit the power comes from, the fuse is there to protect the cable.

What size is it?

 

[NewOrder]

Think its a 1.00mm but might be a 1.5mm, not actually checked the guy who fitted it does have a good electrical background although at the time he had not worked in the industry for a while.

The fuse is 5 amp in the CU from memory.

The control box will be about 60cm from the consumer unit or maybe a bit further as I want to allow enough space for when the spark fits a newer larger consumer unit.

 

[ebee]

without a FCU how would you remove mains power from the control panel prior to opening it up without disturbing the lights?

 

[PrenticeBoyofDerry]

As stated by ebee, if you were to use the the fuse in the fuse box only, you would need to de-energise lighting circuit to gain access to internal workings of alarm when needed.
As it stands nothing electrically unsafe with direct fusing but for convenience reasons down fusing with FCU would be a good option.
But I would consider provisions for the alarm to be on a separate circuit when you install new CU.
As far as part p is concerned everything you do electrically must comply to part p, regardless of whether it is deemed notifiable work or not and any other relevant building controls must be complied to also.
This does not automatically make it notifiable.
In your case your are re-routing an existing circuit, which is not in a special location, bathroom or kitchen. So I would consider that non-notifiable.
Even though it may not be notifiable work, I would expect to have the alteration inspected and tested with the relevant paper work issued.
If the cable/flex is not buried less than 50mm within wall.
So if clipped direct/surface mounted or run in conduit/trunking, or buried within wall deeper than 50mm or mechanically protected, you would not need to introduce RCD protection to this part of the circuit.
If it is buried less than 50mm it would need to be run in prescribed safe zones and have RCD protection or mechanically protection.
Some useful links from WIKI.
//www.diynot.com/wiki/electrics:part_p
//www.diynot.com/wiki/electrics:installation_techniques:route
//www.diynot.com/wiki/electrics:installation_techniques:walls

 

[Alarm]

I always ask or have fitted a 3amp unswitched FCU for any alarm equipment, (Subject to loading).
As it is supposed to be. ( We fail an inspection if it is not).
It needs to be local to the panel for safe isolation for maintenance.
As noted it is preferred to be on its own circuit.

 

[NewOrder]

Thanks never really thought of the isolation point of things . Always had to remove the fuse for the downstairs lighting in the past which has not a major issue as the box was in the hall with lots of light coming in. Now it will be a major issue.

Also when the spark replaces the CU I will ask them to wire it a dedicated circuit, using the existing cable is just a temporary measure.