pulling main fuse

[maguire]

Quite apart from wether or not it is allowed and all the scary vids on the subject surely if there is no load then pulling a 100amp service fuse is safe, I had a discussion with a guy from a supply company who told me that their guys are issued with face shields, gloves insulated tongs etc for this purpose I assume this is because they cannot always gain access to a dwelling etc, this is something we have all done and any time I have to I always ensure that there is absolutly no load, what's the concensus on this in the real world that is
DM

 

[flameport]

The risk is low, however consider what happens if the cutout breaks whole removing the fuse (can happen with plastic as well as older ceramic types).

If suitable insulated tools are to hand then no problem.
If not, you are left holding the broken pieces of fuse/cutout with no way of securing the live parts or even moving them out of the way.

Even with no load, it is not impossible for failure of one or more parts to cause a short and therefore a flash/molten metal etc. There is also the option of removing the wrong fuse from a Ryefield board or similar, so there could actually be a load present.

 

[bernardgreen]

If no load then no arcing when it is pulled, maybe just a little spark due to the capacitive effect in the cables.

It gets a bit nasty when the fuse is holding the cracked ceramic fuse holder together and the fuse holder falls apart.

It gets very nasty if the incoming and effectivley un-fused phase conductor that has just fallen out of the broken fuse holder touches something it shouldn't.

The nieghbours get a bit annoyed when the street loses power, they know who did it as the ambulance calls to collect the person who pulled the fuse.

That is probably the worst case scenario, best be prepared with face shield etc etc,

 

[maguire]

thanks, I agree the risk assement part is a deciding factor here if it looks like a problem then it probably is
DM

 

[1john]

This should perhaps not be discussed quite so in the open here although I have pulled them, making sure they are in good shape first and with no load on them, I have also removed tails from the meter with no load on if the fuse looked iffy. I don not like having to do it but things would never get done. These are situations that we should not have to put ourselves in though and the day that every installation has a main switch for the purpose of avoiding this will be a good one.

 

[bernardgreen]

This should perhaps not be discussed quite so in the open here

Not a problem provided all DIY readers realise

the extremely dangerous and possibly fatal situation they will create if they attempt to pull a main fuse.

 

[maguire]

Yes I agree entirely I sometimes forget that this is in essence a diyers forum and get side tracked on issues assuming a certain level of experience, and I echo the comments on a main switch being provided by the DNO but without saying to much it can be done by them if you know who to ask,
DM

 

[tonyelectric]

Here in the SEC area we are still permitted to pull the fuse ourselves and re-seal with tags supplied by them, The problem I have encountered is when the fuseholder is close mounted to a pitch filled head and the pitch has managed to fing its way into the fuseholder sticking it solidly in place.

I always wear VDE insulated gloves when I pull them and keep a box of assorted carriers (kindly provided by a nice DNO man) in case the bl**dy thing disintigrates.

 

[martinxxxxxx]

Yes I am also in the SSE area and I would always call out the DNO if things look at all fragile instead of going ahead myself. Besides which they normally upgrade everything while they are there which makes the whole job look all shiny and new.

Martin

 

[westie101]

1john wrote:
This should perhaps not be discussed quite so in the open here


Not a problem provided all DIY readers realise

the extremely dangerous and possibly fatal situation they will create if they attempt to pull a main fuse.

A slight correction, the proven fatal situation following the death of a customer in NW England following work on a main fuse/meter by a qualified electrician in 2009(I think)

As regards the PPE the meter inspector that was hospitalised in the 90's would agree to the use of it and the user being trained and qualified to interfere with a DNO main fuse.
The one he was working on looked fine until it exploded in his face

 

[kai]

The safest option is to have a locked DNO cabinet at the end of the street etc, containing the distribution fuses for each house in the row, this way the householder cannot get access to the mains fuses, only the DNO or authorised operators can - Surprised that this method is not used very much - it makes better sense.

 

[westie101]

Except that the network design would not allow it, nor the horrific volt drop to the furthest house

 

[RF Lighting]

It would keep the meter men fit though running backwards and forwards all day long.

I could see safe isolation beeing harder to acheive with that system, and also lots of problems with the wrong fuse being accidentally pulled while the circuit is still on load.

Also a car accident could wipe out the power for an entire street.

 

[westie101]

As an indication of the risk, a DNO system can have up to 630A fuses protecting the LV network.
If a fault arc develops at the mainfuse as it is being removed, there is little chance that a fuse of that size will operate.

You will then have sustained arc in front of you!

 

[flameport]

Also a car accident could wipe out the power for an entire street.

No worse than this piece of equipment just a couple of feet from the road, next to a bus stop and a Royal Mail storage box.

This collection of stuff has a fence around it, but not likely to stop a vehicle.