Anyone Work on live D.B

[Steve93]

Does anyone work live? As lately been working a fair bit ofarmoured and circuits into various boards at different jobs but everytime I do it i think to myself ‘f***them if they can’t live without power for 20 mins’ it’s more like factories and commercial places. What does everyone else do? Just crack on get it done? Or arrange a time to come back and power down?

 

[marconi]

As well as the risks of electric shock, electric burns and electrocution be very mindful of the consequences of shorting lines to neutral or earth - sprayed molten metal, plasma arc flash, eye damage from high intensity arcing, intense heat all to the sound of big bang.

 

[MJPD29]

Your

Respect due,but that is one hell of a lot of new circuits connected,with the reason for not isolating,being more important than your safety,on every occasion.

There are industries and situations,some of which i have worked in,where shutting down sections are "forbidden",yet when they go off as a result of any other influence,the world does not end.

In the majority of production environments,it is usually the cost of lost production,or re-setting lines,which over-rides isolation.

It may be the cost of out of hours wages,for sparks working,when isolating not during production hours.

The point i am making,is these above reasons are monetary,and if you agree that working live,carries increased risk,above working dead,then this risk is taken to benefit someone else,financially.

I have worked HV,where everybody accepts these risks beforehand,and the remuneration reflects this.

To undertake work LV,live,as described by the OP,as part and parcel of a normal routine,requires the kind of consideration,i hope my post,prompts.

Your absolutely correct there it is to benefit someone else financially whether it is the company I am working for or the factory or shop I am working in, but there are exceptions as always if it was completely unsafe obviously I wouldn't do it but there are times when I would deem it acceptable and where I feel I am not putting myself at risk

 

[MJPD29]

Your

Respect due,but that is one hell of a lot of new circuits connected,with the reason for not isolating,being more important than your safety,on every occasion.

There are industries and situations,some of which i have worked in,where shutting down sections are "forbidden",yet when they go off as a result of any other influence,the world does not end.

In the majority of production environments,it is usually the cost of lost production,or re-setting lines,which over-rides isolation.

It may be the cost of out of hours wages,for sparks working,when isolating not during production hours.

The point i am making,is these above reasons are monetary,and if you agree that working live,carries increased risk,above working dead,then this risk is taken to benefit someone else,financially.

I have worked HV,where everybody accepts these risks beforehand,and the remuneration reflects this.

To undertake work LV,live,as described by the OP,as part and parcel of a normal routine,requires the kind of consideration,i hope my post,prompts.

Your absolutely correct there it is to benefit someone else financially whether it is the company I am working for or the factory or shop I am working in, but there are exceptions as always if it was completely unsafe obviously I wouldn't do it but there are times when I would deem it acceptable and where I feel I am not putting myself at risk

 

[Strima]

I work in telecoms and they don't like outages. They are suffering from past years of mismanagement and just throwing kit in to get the money rolling without any foresight.

This now leaves us unable to turn off any equipment as they don't know who it will effect. It could be 250,000 broadband users or the emergency services, know one knows.

I personally don't have a problem knocking off 250,000 domestic broadband users but I don't want to be dicking around with the emergency services, one dropped circuit could impact the ambulance service costing valuable minutes.

Fortunately most systems are -48VDC however this is still treated as a live AC system, with battery UPS we have large fault currents to contend with.

Only those with some form of live working training are allowed to complete these works with the correct PPE and only if they are willing to do so.

Even when I'm wearing the full face shield, double layer gauntlets, flash resistant overalls and stood on a rubber mat I'm still very wary.

Good planning and preparation can significantly reduce the amount of time you're actually live working.

Saying that I don't bat an eyelid when working in a ISOBAR board, I think they give you a false sense of security.

 

[littlespark]

If and when you do work live, what is worse?
An insulated screwdriver with the insulation cut off so it fits into a certain terminal, or an ordinary screwdriver with a bit of 10mm single insulation pushed over the shaft and taped in place to make it 'insulated'

Seen both instances happen.

 

[PEG]

[QUOTE="littlespark, post: 1360754, member: 103809"]If and when you do work live, what is worse?
An insulated screwdriver with the insulation cut off so it fits into a certain terminal, or an ordinary screwdriver with a bit of 10mm single insulation pushed over the shaft and taped in place to make it 'insulated'

Seen both instances happen.[/QUOTE]

...Not sure,about this question,but i'll give it a go...

...so you get out of the shower,put your copper clogs on,and without prior testing,tighten the terminals of a main switch,with your Gerber multi-tool...

 

[marconi]

This web site (of many) provides PPE for electricians.

Electricians PPE - http://www.thesafetysupplycompany.co.uk/c/288117/1/electricians-ppe.html

And a read of the 'Electricity at Work:Safe Working Practices' is instructive:

http://www.hse.gov.uk/pUbns/priced/hsg85.pdf

Here are some images of injuries caused by electricity:

Medscape: Medscape Access - https://reference.medscape.com/features/slideshow/electrical-injuries

or google 'electrical injuries images'

 

[Rpa07]

I thought I was a dare devil swapping over a light switch live, I’m going to rethink my working practices.
I find always being aware of the circumstance when, say, feeding a new circuit into a DB which is not powered down and using the correct tools to give you insulating distance, will keep you as safe as can be. Paying attention and being aware of the gravity of the work carried out will help you live another day.
Im only domestic so make of that what you will BUT ‘amps is amps’

 

[Jim90]

It depends - Crabtree C50 type DB never.
Schneider / Merlin- I have done 100s until the company I work for stopped it. DB has to be powered down now.

 

[elsparko]

 

[Andy-1960]

I had this conversation with an HSE inspector a number of years ago.
Basically, if you work live and something goes wrong and an injury to you or someone else happens as a result, you had better have a good reason for working live. The reason for working live has to outweigh the risk of not working live, so for example, if you isolated a board and it turned off the gas detection system in an oil refinery, that would be deemed a good excuse as other lives would / could be put at risk by turning off the power.
Production or loss of production by turning power off is not seen as acceptable.
One thing to note is if you do choose to work live and an accident does occur as a result and you do not have a good reason, both you, your company and the company you are working for could all end up being prosecuted by the HSE.
Usually when this is pointed out to the customer, it’s amazing how a window of opportunity in production suddenly becomes available!

 

[littlespark]

I remember several years ago getting a memo, as did every employee of a large electrical contracting company, about not to work live.
The memo was about a 2 man team. They were working on a large switchgear set up, and cut corners by leaving the thing powered up. One of the guys absentmindedly leaned his head into a busbar chamber to look for a cable his mate was pushing through a conduit between panels.
This guy lost his life.
The other guy lost his job, and was prosecuted for not insisting the power was off.
No doubt management, and directors of the company would be in trouble too.

 

[AJshep]

About 10 years ago I nearly killed myself !!
It was a really stupid thing to do, I knew the risks but yet I stupidly did it anyway.

We were working on an old Aircraft hanger that had been converted into 8 industrial units 3 large downstairs and 5 upstairs.
Wiring was awful and really dangerous, mostly old VIR tails in metric Conduit all terminated into a Busbar with one main point of Isolation.
The unit we were working on was empty but it had a Busbar before its main switch which also went off to fed 2 other unit's. All the other unit's upstairs and downstairs were occupied, one was 24 hours !!

Anyway there were 4 Phase blocks in the first unit (nearest the main intake) mounted on in metal enclouser the conduit was threaded into this went up and over the roof and supplied the Busbar in the unit we were working in. By pulling the tails out of these phase blocks we could isolate the unit we were working on and the 2 others fed off of it.

So we spoke with the people in the other units, arranged a suitable time to disconnect, and that's what I did. Stupidly !!

Anyway that bit went ok, then, about an hour later a ----ed off lorry driver popped in to see us and started moaning that he had no power to clock out. We looked outside and saw all these lorrys backed up down the road waiting to clock out.

Anyway I couldn't shut off the other unit's so I went back round and put my gloves on and put these crappy old VIR tails back into the phase blocks.
All went well apart from the last one. One of the strands folded out hit the metal enclouser went bang, the phase block physically exploded and shorted to the one next to it.

I didnt get a shock (sounds stupid but I tried to keep at arms reach and not touch anything) but the with the explosion i was blown off the steps, when got off the floor and had lost my Eyebows, Eylashes and had bits of Plastic in my arm that went though the gloves. I thought I was blind too, as I'd lost my sight, and had second degree burns over my whole face too, so I looked like Freddie Kregeur.

Anyway, my boss knew the plan of action and was ok with me doing this, and I just did it as I suppose I was trying to impress.

Don't work live, if you can help it no matter how much pressure people put you under.

## to add it never took the main fuse out.

 

[Marvo]

Glad you lived to tell the tale AJshep, sounds like you had a very close call. What happened to you is typical of the types of events that end up with guys killed by working live. There's nothing you can do to prevent these types of things from going wrong apart from not working live in the first place. PPE gives people a feeling of indestructability but you also only realise how ineffective PPE can be when you witness the aftermath of an incident like this.

........Fortunately most systems are -48VDC however this is still treated as a live AC system, with battery UPS we have large fault currents to contend with........

ELV Battery systems can be far more dangerous and lethal than standard LV networks. Working live on battery systems makes me far more skittish than working live on LV.

 

[sparkdog]

Yes Merlin Gerin no problems, I really like those boards,