Confessions of a DNO engineer!

[Stoday]

Back in the 1950's when I was training with East Mids EB, the standard procedure was for the engineer who isolated the cable to demonstrate it was dead by sawing part through it with a hacksaw.

I think there was one spiking gun for the whole depot, but it was rarely used, only when the engineer wasn't sure.

How times change for H&S!

 

[SimonH2]

Back in the 1950's when I was training with East Mids EB, the standard procedure was for the engineer who isolated the cable to demonstrate it was dead by sawing part through it with a hacksaw.

That's all very well if you know what the cable is and where it's fed from !

 

[ban-all-sheds]

Go back a few years (not that many) and such records would have been kept on paper maps and subject to all sorts of errors - forgetting to update the map, losing it, it going up in a fire, and of course that good old excuse - lost during a merger/acquisition/reshuffle/whatever.

I'd be very surprised if some records had got mistake/omissions/etc that have crept in (or got lost) over the years.

Make your mind up....

 

[SimonH2]

Go back a few years (not that many) and such records would have been kept on paper maps and subject to all sorts of errors - forgetting to update the map, losing it, it going up in a fire, and of course that good old excuse - lost during a merger/acquisition/reshuffle/whatever.

I'd be very surprised if some records had got mistake/omissions/etc that have crept in (or got lost) over the years.

Make your mind up....

OK smart ****, yes there's a typo, that should have been "I'd be very surprised if some records hadn't got ..."

 

[ban-all-sheds]

 

[westie101]

Just remembered these. The effect of a fault on an 11KV 1200A OCB that was slow to clear on the 33kV side

Busbar and feeder chamber

Looking upwards to the fixed contacts

The OCB

As is being discussed in the Copper theft thread, this switchboard was changed (it was a 1960's English Electric board with air insulted busbars!)

 

[SimonH2]

... OCB ...

OCB ?

 

[riveralt]

... OCB ...

OCB ?

Goodness me - don't you know anythink

http://en.wikipedia.org/wiki/OCB_mode


How about an Oil Circuit Breaker?

 

[efiste2]

Those pics are great, they demonstrate the power of the stuff we work with... During my time I have seen a couple of live cables spiked, and have witnesed a few 11kv switches closed on to a faulty cable or an earth....but the protection (we had just commisioned it) worked and no damage was done to the switchgear, although the local 33/11kv transformer did groan a little.....The spiking of a Live 11kv cable was a real eye opener, not because of the explosion but the noise....it was like a pro-longed roar, as it was on a circuit with only very basic protection at the Primary ends.....so it took a second or two to operate.

 

[ban-all-sheds]

http://205.243.100.155/frames/longarc.htm#Disconnect

 

[securespark]

I can imagine what was in their underpants

Ah, now we're getting to the naughty bits!!

 

[securespark]

I am not going to give the location for obvious reasons.

I know where it is! It's in Lancashire!!

Historically, there's been loads of cable thefts in that county.

After all, in the 60's, the Beatles wrote a song about holes in Lancashire...

 

[SimonH2]

Goodness me - don't you know anythink

http://en.wikipedia.org/wiki/OCB_mode


How about an Oil Circuit Breaker?

Ah yes, it's so obvious when you know

I assumed it wasn't Oxfordshire Cricket Board, or Offset Codebook Mode, though Obsessive Compulsive Behavior might be appropriate in this forum at times

http://205.243.100.155/frames/longarc.htm#Disconnect

Takes me back <a few years now> to uni, when the mechanism for creating such arcs was covered in amongst some other electrical stuff I can't remember any more

Those are some awesome videos, and I guess we're quite lucky that they were captured at all.
A friend works at Sellafield, and chatting one day he mentioned that they have blast rooms to retreat into when operating some of the switchgear. The problem being that with Calder Hall (or what's left of it now) next door, they are more or less direct onto the end of a grid feed and so the faults currents available are considerably higher than most places could contemplate.