Isolation is a must!!!!!!!! or this happens

[Darkwood]

Watch this at about 1.08 ..... my first thought and dont ask me why was where was the emergency lighting???




LiveLeak.com - arc flash electrocution

 

[WPD Lad]

The automatic co2 discharge systems we have in some subs is equally as dangerous, the whole place fills so quick you can't see where you're going and you've got no chance of holding your breath!

HV switching isn't all that dangerous as long as you manage the risks, maintain the gear after its been used to fault switch and follow the switching schedule, we have very few erroneous operations and most just result in losing supplies to customers and not hurting people. Our new gear is rated at 350MVA fault current so you're very safe using this stuff

 

[Knobhead]

It all comes down to training and following procedures. Very rarely will you not have a switching schedule. Sometimes a switching procedure may seem time wasting, but it’s done for good reason.
Occasionally you have to think on your feet, only twice have I had to carry out emergency switching to restore power on my own. Normally even for restoring power it would be planed out along with another engineer.

 

[Darkwood]

Im sticking to LV..... at least you have a good chance of remembering when you c..k it up!

 

[Engineer54]

The automatic co2 discharge systems we have in some subs is equally as dangerous, the whole place fills so quick you can't see where you're going and you've got no chance of holding your breath!

HV switching isn't all that dangerous as long as you manage the risks, maintain the gear after its been used to fault switch and follow the switching schedule, we have very few erroneous operations and most just result in losing supplies to customers and not hurting people. Our new gear is rated at 350MVA fault current so you're very safe using this stuff

As WPD states, MV/HV switchboards need that little bit more love and care as regards to maintenance and cleaning schedules, things need to be scrupulously clean anywhere around moving contact points/areas. How often you see this now days is another matter!!

On some of the modern switchboards you can have local/remote motorised racking in and out of breakers, which would take away most of the the risks of injury and death from arch flashes, but wouldn't safe guard the boards themselves... And they are bloody expensive to incorporate too!!...lol!!

As for auto gas discharge fire suppressing systems, they are never instantaneous, they should all have a first alarm (evacuate alarm) followed by a second alarm with a minimum 60 second delay on release. I have seen on occasion the 60 sec delay being applied to the initial alarm, but very rarely where personal are present... These suppression systems can do more physical damage than the fire itself if the system pipework isn't solidly fixed to substantial equally solidly fixed brackets. The pressure these systems works under can rip there pipes from normal ceiling brackets and pipe clamps in a second, and will smash anything in there way!! Just imagine a heavy walled rigid steel pipe acting like a fireman's hose pipe that's not being held...lol!!!