changing a fuse in a fuse box

[kai]

Hager breakers are available for that type of fuse box, which clip onto the din-rail, in place of the fuse holders. 1) Electrician will need to switch off, 2) remove the front cover by the two quarter-turn screws, 3) then slacken off the clamp screw on the base of the fuseholder, 4) then release the upper screw clamp containing the circuit phase core. 5) Unclip the fuse holder with an electrician's insulated screwdriver inserted into the little catch at the base of the fuse holder. 6) Clip in the replacement breaker onto the din-rail, 7) tighten the lower clamp screw to engage with the busbar. 8.) reconnect the phase core into the top cable clamp on the new breaker. 9) restore supply.

 

[EFLImpudence]

I assume this was aimed at me?

does the fuseholder incorporate a switch ?

As you know, the fuse carrier is the switch.

or are you just relying on the arcing not being too severe?

What is the difference between this and pulling out one in a 3036 type holder?


If the OP doesn't want to do it, fair enough, but she was worried about the alarm sounding if the power was cut.

Don't tell me you would isolate the whole house to replace one of these fuses for a lighting circuit.

 

[JohnD]

What is the difference between this and pulling out one in a 3036 type holder?

None. You're not supposed to pull out or replace a fuseholder under load.

Don't tell me you would isolate the whole house to replace one of these fuses for a lighting circuit.

I would isolate the supply to the circuit before removing or replacing the fuseholder. If this can only be done using a main switch which disconnects several other circuits at the same time, so be it.

 

[Iggifer]

I would isolate the main switch before removing and especially re-inserting a fuse, especially a 3036, so much safer

 

[EFLImpudence]

What is the difference between this and pulling out one in a 3036 type holder?

None. You're not supposed to pull out or replace a fuseholder under load.

Then switch off the lights.

Don't tell me you would isolate the whole house to replace one of these fuses for a lighting circuit.

I would isolate the supply to the circuit before removing or replacing the fuseholder. If this can only be done using a main switch which disconnects several other circuits at the same time, so be it.

Table 53.4 states that BS88 fuses (which these are now) are a suitable means of isolation.

 

[MeterMonkey]

None. You're not supposed to pull out or replace a fuseholder under load.

Without wanting to side with anyone and this is a genuine question.

Theoretically, If the fuse has gone, isn't the load already isolated?

 

[RF Lighting]

No. There is still a load connected.

Personally I would turn of the main switch before closing the fuse carrier or inserting a 3036 after it has failed and the cause of the failure is still not known.

If there's still a fault on the circuit, closing the fuse onto it is going to damage the fuse holder possibly to the point where it needs replacement, and there's also a a risk of the OP sh---ing themselves, and possibly getting burnt.

In industrial settings it's not always possible to insert fuses dead, but where ever possible I do, and would certainly advise a DIYer to do so.

 

[Iggifer]

Especially a 3036, nobody wants molten fuse wire in their face!!

 

[JohnD]

means of isolation.

isolation ≠ switching

A fuseholder is not suitable for switching a circuit under load.

 

[andreaccc]

errr now im confused - i thought that changing the fuse was supposed to be simple ????

managed to do this without problems in my other house as i was familiar with it - but i always turned off the mains - im not familiar with this one at the new house

yes - i was worried about the alarm but my father did have work done on the hosue in the past he has had some new lights so i suppose the electricain would have turned off the supply to fit them - and maybe the alarm has a battery back up ? im gonna wait until my sis returns from holidays on this one as she a bit more familiar with dads house than i am

ps does 'op' mean old age pensioner ????

interestingly enough i do have the little spotlights all over the kitchen celing and its those which have gone as well as in the hall and the kids were going in an out the kitchen xmas day lights were on a lot so might have something to do with that and main light gone in front room but we still have spotlights in the front and lampps so we are ok

 

[EFLImpudence]

isolation ≠ switching

No, I know but isolation does not depend on something else being isolated first.

 

[Iggifer]

op means original post or poster

Recent posts have just been about whether you need to turn the main switch off to change the fuse.

Do whatever you feel safer with, but I personally couldn't recommend doing it with the main switch on. There's no harm in turning the power off to change the fuse (besides having to reset cooker clocks etc but that's hardly the end of the world)

 

[JohnD]

...but isolation does not depend on something else being isolated first.

A isolator which is not suitable for switching a circuit under load, is intended to isolate that circuit once the load has been disconnected.

A fuseholder is one such device.

 

[RF Lighting]

OP, I know we've digressed a bit as we tend to do, but all you need to do is turn off your main switch, open the fuse carrier by pulling it at the top. It's hinged and will open to reveal a fuse. Remove this fuse. It'll be loose, so will come out dead easy.

Then you can put the power back on whilst you nip to the shop. You need to purchase a bs1361 fuse. These are not the same as the fuses you put into plugs.

Your local hardware shop should have them, and your local electrical wholesaler and B&Q etc will have them for sure. You can reserve one online here and collect it instore so you know you've got the correct one if you like.

Then turn the main switch off again, pop the new fuse in, close the drawer and turn the main switch back on.

You don't need to worry about your alarm. It'll have a backup battery to keep it going whist the electricity is off.

 

[EFLImpudence]

A isolator which is not suitable for switching a circuit under load, is intended to isolate that circuit once the load has been disconnected.

Not so with the fuse in an unswitched FCU.

I fail to see the difference.