On the subject of pulling the DNO fuse.

Hello Pat,


I seem to have opened a can of worms!


You've asked some good questions and have raised some good points.


To answer your first question, the answer's no! I can't tell you how many non-DNO staff have been injured pulling the DNO's fuse, I don't have access to that information (and probably never will), but you've raised a good and valid point - plus the tone of your question suggests that you don't think it's very many, and I agree with you - I don't suspect it's very many either.


It's the fact that it's illegal, and the potential consequences of it going wrong, that I'm trying to get across. I know you're all more than capable and more than competent, (and I know you've all done it), but what I'm saying is you'd be on a very sticky wicket if something went wrong. Whilst the odds of it going wrong are admittedly slim, it does happen, and when it happens it can really spoil your day. I've seen a service termination go up like a small bomb (ISCO single phase 60A metalclad on a 2c 04 PILC service), and if it had happened while somebody was working on it, that person would definitely have received burns, and would probably have been blinded. There were pellets of melted copper all over the opposite wall in the cupboard. Plus it took a 315A fuse in the substation a couple of streets away, plunging roughly one third of the customers on that feeder into darkness. So don't risk it please! 


To address your second point, I'm not aware of private electricians being issued with seals by the DNO - in my experience, I've never heard of this being done. Which DNO's do this? And do they operate any assessment or accreditation for it? I can only assume that if a DNO has issued an electrician with a set of sealing equipment, then that electrician has been assessed and recognised by the DNO as competent to work on their equipment, and as such can remove the fuse where necessary.


Re isolators being fitted (or not) - Prior to the late 80's, early 90's, the only isolation between the cut out and the customer's wiring was the main switch in the consumer unit. This had been standard practice since the year dot, rightly or wrongly. DNO's began installing isolators around the early 90's as standard on new supplies and service alterations, the top side (from the meter) being sealed with a wire seal, and a plastic seal on the customer side with a disclaimer notice attached. Then there was a period when meters were supplied with an integral isolator, being either of the traditional switch design or a rotary switch operated by a screwdriver. These meters had a split terminal cover, with the incoming supply side being wire-sealed. My personal opinion is that an isolator should be fitted as standard on all new supplies, and retrospectively at periodic meter changes. Would solve all kinds of problems and put these arguments to bed once and for all.


I do stand by my position on the legality and risk of interfering with DNO equipment, however for what it's worth - I think it's an insult to the intelligence of any registered electrician to have to call the DNO simply to pull a fuse, but that's the way the law stands, and whether you agree with it or not, that's what you're required to do. Bear in mind that I'm posting to this forum in my capacity as a DNO's SAP - and as such I have to uphold the regulations and safety rules. That doesn't mean I can't see your viewpoint - I can. Many years ago, as a 20-year old having just completed his apprenticeship, I felt a complete fraud having to pull a cut-out fuse for an electrician who'd been in the trade for over three times as long as I'd been alive. So I do see your points, and you have a perfectly valid argument, but I'm sorry, legally you can't do it!


That said, I'd reiterate the point I made in a previous post - I'm not aware of anybody having been pulled up or reprimanded for having removed the DNO's fuse in order to work safely. 


   

Hello Pat,


I seem to have opened a can of worms!


You've asked some good questions and have raised some good points.


To answer your first question, the answer's no! I can't tell you how many non-DNO staff have been injured pulling the DNO's fuse, I don't have access to that information (and probably never will), but you've raised a good and valid point - plus the tone of your question suggests that you don't think it's very many, and I agree with you - I don't suspect it's very many either.


It's the fact that it's illegal, and the potential consequences of it going wrong, that I'm trying to get across. I know you're all more than capable and more than competent, (and I know you've all done it), but what I'm saying is you'd be on a very sticky wicket if something went wrong. Whilst the odds of it going wrong are admittedly slim, it does happen, and when it happens it can really spoil your day. I've seen a service termination go up like a small bomb (ISCO single phase 60A metalclad on a 2c 04 PILC service), and if it had happened while somebody was working on it, that person would definitely have received burns, and would probably have been blinded. There were pellets of melted copper all over the opposite wall in the cupboard. Plus it took a 315A fuse in the substation a couple of streets away, plunging roughly one third of the customers on that feeder into darkness. So don't risk it please! 


To address your second point, I'm not aware of private electricians being issued with seals by the DNO - in my experience, I've never heard of this being done. Which DNO's do this? And do they operate any assessment or accreditation for it? I can only assume that if a DNO has issued an electrician with a set of sealing equipment, then that electrician has been assessed and recognised by the DNO as competent to work on their equipment, and as such can remove the fuse where necessary.


Re isolators being fitted (or not) - Prior to the late 80's, early 90's, the only isolation between the cut out and the customer's wiring was the main switch in the consumer unit. This had been standard practice since the year dot, rightly or wrongly. DNO's began installing isolators around the early 90's as standard on new supplies and service alterations, the top side (from the meter) being sealed with a wire seal, and a plastic seal on the customer side with a disclaimer notice attached. Then there was a period when meters were supplied with an integral isolator, being either of the traditional switch design or a rotary switch operated by a screwdriver. These meters had a split terminal cover, with the incoming supply side being wire-sealed. My personal opinion is that an isolator should be fitted as standard on all new supplies, and retrospectively at periodic meter changes. Would solve all kinds of problems and put these arguments to bed once and for all.


I do stand by my position on the legality and risk of interfering with DNO equipment, however for what it's worth - I think it's an insult to the intelligence of any registered electrician to have to call the DNO simply to pull a fuse, but that's the way the law stands, and whether you agree with it or not, that's what you're required to do. Bear in mind that I'm posting to this forum in my capacity as a DNO's SAP - and as such I have to uphold the regulations and safety rules. That doesn't mean I can't see your viewpoint - I can. Many years ago, as a 20-year old having just completed his apprenticeship, I felt a complete fraud having to pull a cut-out fuse for an electrician who'd been in the trade for over three times as long as I'd been alive. So I do see your points, and you have a perfectly valid argument, but I'm sorry, legally you can't do it!


That said, I'd reiterate the point I made in a previous post - I'm not aware of anybody having been pulled up or reprimanded for having removed the DNO's fuse in order to work safely.