Left hand rule

[Knobhead]

An extract from a letter I wrote many years ago based on American recommendations.

With any HV / LV switching operations follow the “Left hand rule”.
IE Never operate a switch with your body directly in front of the switch. If the operating handle is to the right of the switch, stand to the right & use your left hand to operate the switch.

Believe me! It’s no fun when the switch lid goes flying past your head! (It happened to me with a BILL Royal switch)

 

[stansmith]

ive seen people operate ocbs with pieces of string from outside the switchroom, and ive seen new panels with lines cut around the fixing screws on the covers at the back to weaken them so the pressure blows out the back rather than the front seems like a good idea just incase

 

[Knobhead]

You can’t beat the bit of string! (Lanyard) all GEC breakers up till about the 70’s had the loop for you to tie on to. I’d rather be 20 yards away than stood in front of the bloody thing!

I’m informed that eternity is a long time dead. (No confirmation though).

 

[bomjac]

Did a ring main upgrade back in my apprentice days. Went around isolating, spiking and cutting all the old cables from the switchgear (circa 1950s English Electric 11kV OCBs). The tripping and spiking was done from outside the Sub by a length of string.

Never really understood the forces involved till a 3.3kV trailing cable with our "find the fault" 500 amp fuse fitted blew out 4 feet away from me.

But the latest school of thought now is even for the large 440 volt breakers, flash suit, gloves and visor is the correct PPE. Below is the kit in use, ready to phase in a new 13.8kV generator for the first time (my mate got the short straw, hes the one with the phase sticks, Im holding the safety hook).

 

[stansmith]

is the substation on the moon lol

 

[bomjac]

HAve a watch through these then youl realise why the suits are necessary. They could be the difference from walking away from an accident and dieing a painful death over a few days form 3rd degree burns.

http://www.youtube.com/watch?v=dPJtknGmsys&feature=related]Arc flash Accident - YouTube

[URL]http://www.youtube.com/watch?v=dPJtknGmsys&feature=related[/URL]

 

[Knobhead]

How things have changed, last time I did phasing out I was the Martian. The first time I was wearing a tee shirt and shorts!

I’ve got to admit I didn’t like doing it at all! I would try and find anyway possible to avoid it, normally testing on the LV side if at all possible. Our records held all joint / termination core numbers so we could guarantee (99.5%) that if the LV phasing was right the HV would be. The proof in the pudding being closing the OCB. It never went wrong for me but there’s always that chance. If it does go wrong get away and let the remote systems take care of the fault. Don’t do the knee jerk and try to open the OCB, that’s asking for disaster.

I’ve deliberately closed an OCB on to a known fault to break down a high resistance, but the bit of string was always used!

One thing I never want to have to sort out again is a switch failure. I was chiselling bits of porcelain out of the brickwork!

 

[Knobhead]

arc flash 4160volts - YouTube
The guy uses the left hand rule.

 

[vaughant]

Guy with us had a 415v belmos panel blow straight out in front of him,nasty horrible things those,all metal clad with no visible areas,I hate working on them.

 

[Knobhead]

Bellmos Peebles have got a long history and reputation, non of it good s far as I’m concerned!

 

[MarkieSparkie]

From henceforth to be known as "Tony's Left-hand Rule". Just keeping up with Fleming's don't you know!:joker:

 

[Knobhead]

It was what I was taught as an apprentice, it’s saved my life once. Therefore a good reason to pass it on.

I never want to witness anything like this again

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