Why is there a fuse in my loft?

[Puggit]

We have an approx 6 year old David Wilson house, up in the loft there is a box with a 13amp fuse in it. One grey flattish cable enters, and I can't see any exit for cabling:



Nearby there is the cabling for the non-installed alarm system.

Any ideas? Is it as obvious as it seems (ie power for alarm)? I can't see how to draw power out of the box though...

Thanks!

[Muncher]

Extractor fan or shower perhaps?

[Alfa numeric]

Could it be a provision for a light up there?

[Fer]

Pull the fuse and see what stops working?

[Puggit]

It's above our spare room, and a fair distance from the 2 bathrooms. I'm guessing it's for the alarm, but surely that wouldn't need 13amps?

[Puggit]

Fer said:

Pull the fuse and see what stops working?

Nothing changes. As the cable enters but doesn't leave, I'm assuming nothing is powered through there.

[anonymous-user]

Puggit said:

I'm guessing it's for the alarm, but surely that wouldn't need 13amps?

It wouldn't but the box prob. came with one as standard as that is what it will be rated to.

[Meeja]

As has been said, an alarm panel would not need 13A, but the spur unit probably came with a 13A fuse as standard.

Spec is correct for an alarm panel as well (unswitched) and ideally, it should be run from the non-RCD side of a split consumer unit, via it's own RCBO (Thay way if the RCD trips, it will not remove power from the alarm system, and the alarm system is still protected by the RCBO)

Unlikely it has been configured that way though....

[Puggit]

Meeja said:

As has been said, an alarm panel would not need 13A, but the spur unit probably came with a 13A fuse as standard.

Spec is correct for an alarm panel as well (unswitched) and ideally, it should be run from the non-RCD side of a split consumer unit, via it's own RCBO (Thay way if the RCD trips, it will not remove power from the alarm system, and the alarm system is still protected by the RCBO)

Unlikely it has been configured that way though....

Ha!

Funny you should say that... I've just tried to work out which RCD it is wired through so that I can safely connect something in to the box permanently and I can't find a trippy thing that switches it off. As I'm planning on wiring in external security lights (2x75W) to this box I'm not sure if that's a good thing...

[Meeja]

It is probably spurred off the upstairs ringmain. Is it possible to trace the T&E cable that enters the spur?

[Puggit]

Meeja said:

It is probably spurred off the upstairs ringmain. Is it possible to trace the T&E cable that enters the spur?

It's all hidden under masses of insulation that I have no desire to move! Tripping the 4 switches for upstairs/downstairs lights and upstairs/downstairs mains didn't cut the power. It did piss my wife off however, as when I warned her to warn our son that his computer was about to go off, she didn't think that applied to her too

[Meeja]

Firstly, at the wife!

Sounds a little odd that you can't isolate it... What are you using to test the fuse spur to establish whether it is still live or not?

[bimsb6]

Meeja said:

Firstly, at the wife!

Sounds a little odd that you can't isolate it... What are you using to test the fuse spur to establish whether it is still live or not?

the wife with a wet finger i hope .

[hidetheelephants]

bimsb6 said:

Meeja said:

Firstly, at the wife!

Sounds a little odd that you can't isolate it... What are you using to test the fuse spur to establish whether it is still live or not?

the wife with a wet finger i hope .

[Simpo Two]

What do you intend to do if you ever find out what it was for?

[Puggit]

I've opened it up, there's an in cable, and connectors for an out. So I'm wiring in a 4 way adaptor and setting up a light in the loft and one outside. This leaves 2 sockets for a train set some day

[Meeja]

Puggit said:

I've opened it up, there's an in cable, and connectors for an out. So I'm wiring in a 4 way adaptor and setting up a light in the loft and one outside. This leaves 2 sockets for a train set some day

Only viable if the incoming twind and earth is 2.5mm (ie spurred off a ringmain or similar)

If the incoming is 1.5mm (or even 1mm) then it is probably linked to a lighting circuit somewhere, and putting sockets on that you can load up is dodgy ground.

Still haven't established where it comes from though.... Are you in a semi, and it is fed from next door?!

[Puggit]

Meeja said:

Puggit said:

I've opened it up, there's an in cable, and connectors for an out. So I'm wiring in a 4 way adaptor and setting up a light in the loft and one outside. This leaves 2 sockets for a train set some day

Only viable if the incoming twind and earth is 2.5mm (ie spurred off a ringmain or similar)

If the incoming is 1.5mm (or even 1mm) then it is probably linked to a lighting circuit somewhere, and putting sockets on that you can load up is dodgy ground.

Still haven't established where it comes from though.... Are you in a semi, and it is fed from next door?!

Nope, we're detached! Definitely not the lighting circuit(s) as I checked that.

[Meeja]

I am still intrigued as to where the feed comes from.... Turn off the main incoming breaker on the Consumer Unit and see if it is still live.... If it is, then this will be a fun ride!

[Puggit]

Meeja said:

I am still intrigued as to where the feed comes from.... Turn off the main incoming breaker on the Consumer Unit and see if it is still live.... If it is, then this will be a fun ride!

I'm waiting for everyone to leave the house today before I do that! You never know what Mrs Puggit is doing on the 'net