removing main fuse for changing consumer unit

[holmslaw]

..

 

[The Dentist]

if the meter is a new digital version, some have built in isolation switches under the cover, so you wont need to pull the 'scary' fuselink

 

[AMEdinburgh]

Excuse my ignorance TTC but I dont' understand why removing the fuse cartridge doesn't make it a safety device. I understand that, in place, it is an over current protector and a double pole isolator would be the ideal solution but pulling the fuse surely removes all sources of voltage from the entire building??

 

[NotHimAgain]

Right is stating that there is a risk of arc flash OTT.

Well yes if we are considering arc flash like [http://www.metacafe.com/watch/1555440/arc_flash_while_racking_a_breaker/] this - but definitely not if we consider a smaller flash that could give you first degree burns and may blind you.

The risk is from failure of the cut-out or the supply cable.

1) Cut-out fuses are not designed for use by unskilled person.
2) Any professional would first assess the condition of the cut-out - can you do this.
3) Old units can indeed have earthed metal enclosures.
4) If the cut-out fixings fail as you pull the fuse you may damage the supply cable - especially if it is an old lead sheathed type with an EC15 earth clip (which should not be used) fitted.
5) Removing the load will not prevent arc flash if the cause is a fault. The sort of flash you get from a load is peanuts. [/wiki]

 

[leeco]

i've took these fuses out a few times the 1st few times i didn't isolate the c/u and was getting arching very scary then i sussed out if i cut all the load to the c/u then there was no arching

 

[FingRinal]

Pulling the main fuse wouldn't satisfy EWR1989 on TT systems anyhow.

I've often wondered how that would be squared off from a legal point of view if a DNO took the easy path and told you to install an earth rod because they had decided that TNCS was mysteriously now out of limits.

Would they have to turn up anyhow to fit a DP switch to save them the bother of getting the jointing team in to make things safe?

 

[Master of None]

quote
i've took these fuses out a few times the 1st few times i didn't isolate the c/u and was getting arching very scary then i sussed out if i cut all the load to the c/u then there was no arching

 

[mattylad]

1) Cut-out fuses are not designed for use by unskilled person.

This is a particular skill they teach is it, how to pull a fuse? does it come with a certificate?

2) Any professional would first assess the condition of the cut-out - can you do this.

What, you mean look at the fuseholder and see if it looks like it is likely to fall apart or break?
Yes an ordinary person with a good level of competence should be able to assess that just as well, or do you have special xray glasses to see whats inside?

4) If the cut-out fixings fail as you pull the fuse you may damage the supply cable - especially if it is an old lead sheathed type with an EC15 earth clip (which should not be used) fitted.

Sorry? your saying that there is a cutout in there as well as a fuse?

5) Removing the load will not prevent arc flash if the cause is a fault. The sort of flash you get from a load is peanuts.

So what your saying is that these things are badly designed & highly likely to fall apart when removed.

Surely the DNO's should be changing them to a safer design as they are obviously not safe?

 

[NotHimAgain]

Be as flippant as you like its really not my problem - but I can assure you that cut-outs (that is the name of the whole assembly) - can and do fail - can and do break loose from their, often poor, fixings - and this can result in an old paper insulated lead service cable failing.

The bang will definitely cause a change of under pants - let's hope you never find out the hard way.

 

[mattylad]

OK, and so how many of you sparkies on here have never pulled one?

And those that have, what happened, has it ever actually done any of this to you?

 

[aptsys]

I've had the fuse carrier come away from the fuse, fortunately it was repairable, but not without getting the fuse out first...

 

[333rocky333]

2) Any professional would first assess the condition of the cut-out

Had at least 6 burnt up or jammed in and had to call out the board

3) Old units can indeed have earthed metal enclosures.

seen a few even the board were wary of touching

4) If the cut-out fixings fail as you pull the fuse you may damage the supply cable

Had one recently the back part of the carrier just pulled off the wooden back board, luckily it stayed attached to the cable.

Edf man, recently told me a few of there employers have been injured and some even killed recently, carrying out there work.

 

[mattylad]

Had at least 6 burnt up or jammed in and had to call out the board

so an Electrician pulling a DNO's fuse eh, what was that about being the property of the DNO?

 

[securespark]

OK, and so how many of you sparkies on here have never pulled one?

And those that have, what happened, has it ever actually done any of this to you?

I have indeed.

But not before donning insulating gloves & goggles. And taking a great deal of care. And getting permission.

 

[RF Lighting]

OK, and so how many of you sparkies on here have never pulled one?

And those that have, what happened, has it ever actually done any of this to you?

I've have removed DNO fuses.

I have had a new style BS1361 holder with a mising screw which the plastic covers came off leaving a live fuse still stuck in the cutout.

I have also had an old style BS3036 ceramic fuse holder (the ones in the earthed metal cutout) snap. That resulted in the DNO having to attend and replace the cutout.