Power Turns On Ep.102

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Thank you, be safe, and be grateful.

[lahollander]

Well that was a nice PSA on electrical safety I wish I knew decades ago.

[littlewingpsc]

Standing clear of the electrical panel when energizing circuits is sound advice. When I was in college, studying to be an Electrical Engineer, I was lucky to CO-OP at a electrical utility in Florida. While working there one semester, one of the Engineers and I went out into a sub station yard to conduct a Power Factor measurement test on a Combustion Turbine generator. We had the test instruments wired into the terminals of a secondary transformer whose contacts rolled and engaged the bus wires after you closed the access door. Unknown at the time, was that the test leads crossed as the transformer contacts rolled and engaged. Once the Combustion Turbine was turned on, we had a instant Phase to Phase short which quickly burned through the wire insulation, caused arcing in the transformer cabinet, and ignited a dust explosion. The fire ball that shot out of that cabinet sheared a 1 inch thick locking bolt, and blew the door and a lot of debris across the substation yard. I had just cleared the front of the door as the power plant electrician turned on the generator to run the test, and felt the heat, and saw the flash out of the corner of my eye. I'm glad I wasn't in front of that door. Made a huge mess. Spent the rest of the day writing up a safety report, and being told I was lucky. Electricity is serious stuff.

[jamesogorman]

I would add another safety point by telling a story.
As an oil refinery carpenter, we were instructed, when working around rotating equipment, to lock out the breaker, then throw the switch to ensure there is no power.
We once had a job on top of a cooling tower with a 25 foot propeller fan just overhead. We switched off and locked the breaker with our lock, then climbed up and turned on the switch. ROAR!, on came the fan.
A metal bar inside the breaker had deteriorated over time, so the outside handle was not making contact with the switch inside the breaker.
I became a firm believer in lock out procedures that day.

[mcarroll]

23 years in the electrical trade. One of the first things I learned when I was an apprentice. Stand off to the side when energizing equipment!

[quiescentnexus]

If you're wondering what's the deal with standing off to the side, here's a story for you. (tl;dr: now I know what a HALF MEGAWATT short circuit looks like up close.) A few years ago I needed to change a blown fuse in a distribution panel that happened to be a 1950s Soviet vintage (this happening in Central Europe, those things are still around over here), all cast iron enclosure with exposed 6x30mm [~1/4"x5/4"] solid aluminum 3-phase bus bars mounted on bakelite. The panel was being fed from a local 460kVA 15kV stepdown transformer located in an adjacent building, with a 60m [180ft] run of 4x120mmsq cable (this is 4x0000ga for american folks - four zeros, that's not a typo). The fuse in question was mounted directly above bus bars and unknown to me at that moment, it was cracked right in two - so as I pulled it out, one half of it, along with one contact surface, fell right onto the bus bars and wedged itself there.

As soon as the arc started at that chunk of the fuse, it began scooting up and down the bus bars, crackling and buzzing like mad, throwing chunks of molten aluminum around and burning through the bakelite mounts. This lasted for almost 10 seconds, wreaking further havoc inside the panel, before the fuses on the *primary* side of the 15kV transformer gave up. I got away from that without any injury because I didn't trust the damn thing in the first place and made a point of always wearing certified lineman gloves and eye protection whenever working on it, but it was still quite an experience. It sure took me a few minutes to regain composure and start assessing damage. According to some quick calculations I made later that day, that arc definitely exceeded 550kW and might have reached 700kW, depending on the transformer's secondary winding impedance.

Oh, and I never found that chunk of the fuse in the wreckage. It must have been vaporized completely.

[MrJramirex]

If an old lineman tells me to never face the breakers while turning them on then I will never forget those words and take his advice. The guy has lived long enough to have seen things and survived things. Big respects and admiration for what lineman do.

[Jessassin]

Linemen work for their money, that's for certain. However given their criticality to our modern world, I would say that they are severely undervalued.

It's always great to hear you talking up the importance of professionals.

Also, that tip about standing clear of the breaker box is great, and a similar approach should be taken whenever energizing electrical equipment. Arc flashes & vaporized metal are no joke. Whenever I try to emphasize the importance of PPE for flash protection, I always mention that arc flashes are measured in "calories per centimeter squared" - meaning there is a huge amount of energy concentrated in a very small area.

[dannydo]

Thanks for the shoutout to the Linemen Scott! 22 years on the job.

[DaCoder]

Always a treat to hear an expert give some advice for free.

[thallmeister]

I work around 480v switches as a die maker, they recommended that we hold our breath while we flip the switch. That is suppose to help prevent you from gasping and inhaling the flames/debris. It makes sense, but at home I'm guilty of not following that same standard of precaution. My hat is off to linemen, that's a tough job.

[Jerrodplanck]

Everyone always thinks the rule to stand off to the side is hogwash. That is until they have a breaker blow up on them. I’ve had three blow up on me in my career as an electrician.

[Anglo-EgyptianMan]

wow, I've never heard that thing about standing to the side before

[johnalexander]

There was a LOT more going on in that video than any non-sparky will ever know, from the specialised tooling to the Penetrox and the torque shear lug bolts. This could have been an hour long and still not covered everything.

[bradgotschall]

Look up “Arc Flash “. You’ll learn respect for electricity. Nice commentary on power company linemen. Most folks don’t realize the dangers they face and sacrifice they sometimes make during large storm outages. Looks like a great job on sunny days but not so much during storms and winter weather.

[ourv]

WADS,
Years ago I was on a job one Sunday in Mountain View, Ca when I found my L2
leg only was supplying 80 volts. I called PG&E who sent out a lineman. It took
this guy about 20min to determine my problem was way up on top of the power pole out on the street. This guy used the man lift on his service truck to get him to the top
of the pole & in a winter storm pouring rain & howling wind he went up there
handling hot power wires & made fresh electrical connections on top of
that pole. MAN. Those guys got brass ones!

!

[sandollor]

Loved that little bit at the end when the lineman was speaking about safety. Another great video, thanks!

[gavinsheehan]

Its great to see the house finally coming together so far its been a joy to watch this series thanks for the great content and for teaching me so much

[waldinjo]

I've got so much respect for the guys keeping our infrastructure growing and maintained

[StoneysWorkshop]

That tidbit at the end comes from a man with experience!

[Elkadetodd]

Temping for the power company changing meters. All was fine for a few thousand houses. Roll the meter out (so you pull the top hot lugs first), push the new one in, do some paperwork.
Then I rolled one out that had both a bypass lever and a chrome ring around the meter. Ring shorted across the still-hot bottom lugs. I was mighty glad I had my eyepro on...