'bout bit the big one today...

I am a maintenance mechanic for the local city water utilities. We have been under construction for a new process and we had wired up a temporary feed to a motor that will be eliminated when the new project is done. (480V 3PH power BTW) Well, the project is done now and I was told to remove the wiring and control panel for this motor. I wasn't planning on doing it all today but I wanted to at least remove the power cable from the panel so that I could close the window that the power cable was running through...it be cold ya know.

So I turned the motor off and opened the panel to loosen the wire terminal screws after following the appropriate wires (I thought) to their source. The terminal screws were kinda down in, and my screwdriver wouldn't fit...so I whip out my handy dandy swiss army knife and proceed to loosen the screws...no problem so far. But...heres where things got scary, once all three screws were loose I pulled the wires out and KABOOM! Anybody that is familiar with 480V knows that KABOOM was accompanied by a ball of fire too. Surprisingly I didn't have to peel myself off the ceiling. I quickly realized that somehow I had a complete brain fart and had pulled the line power instead of the load side...and it was not turned off!! I didn't want to kill the breaker feeding the line side because it was feeding something else that I didn't want to kill...STUPID!

So once I took inventory and decided that I was completely unscathed, I figured I better check everything out...yup E-lights were on so building power was out...it had blown the 50A breaker that was feeding the subject motor, and had opened the main 400A breaker feeding the building! I reset the main and set back down to go about my business...it was at that point I realized that I had loosened those terminals with live 480V power on them...using an all metal swiss army knife screwdriver...without so much as a tingle! I thought how could this be....maybe it had some kind of weird insulated terminal screws...got out my meter to check..nope! It's about that time that it occurred to me...it's a miracle I'm still alive...seriously. People that work with electricity know that 480V 3 PH is nothing to mess with...you usually don't just get shocked...usually, it is a very serious hospital visit, if you are even still alive. The stats say that more people die from 480V electrocution than any other voltage.

Looking back, what did I do wrong...man, it's a laundry list.
Didn't kill the panel feed power
Didn't make double sure I was working on the right terminals (especially since the panel was not completely dead...and I knew this!)
Didn't verify with a meter that the power was dead.
Didn't use a insulated screwdriver
Didn't have safety glasses on
Probably more...

Geez Louise, what a dumb thing to do...I know better...for you guys that work on electrical equipment...this is a reminder, don't get sloppy! Gotta go home to your family at the end of the day...and I'm sure the boss types would appreciate not being caused a ton of paperwork!
Bottom line, "There but by the grace of God go I"!

 

I am not sure how to respond to this, you are a very lucky man. I did something very similar with 220, and I thought I got lucky

 

So glad you survived and are okay, a miracle for sure..........................now after you kick yourself in the arse, go buy a lottery ticket.

 

Glad your OK brenndatomu Gramps was a electrician, yeah he told me ALWAYS check twice.. now think about a lottery ticket cause ... You should be feeling lucky!

 

Yes

Oh, no worries, I'm sitting here watching my son play on the floor and kicking myself in the butt big time!

 

I dunno, I think cleaned out the "luck" bank...maybe even took out a big loan too

 

Just glad you got home to play with son

 

Glad you walked away unscathed.
Thank the relaying on the 400A main for saving you from a fireball.
Any chance your employer has had an arc flash study and is following NFPA 70e?

 

We did the study a couple years back, but nothing more ever came of it after all the panels were labeled

 

Dude, you must be doing really good stuff all the time because karma just paid it's mortgage off on you. I've seen that fire ball firsthand.

Uninsulated Army knife,
No face shield,
no Inulating gloves,

The only rule not being broken was standing in a puddle(maybe your were, didnt say)

OMG kiss your wife twice tonight before bed.

Truly happy that we get to read your post,

 

That's why you're fine
hard to explain why you weren't electrocuted with a pocket knife though -Good boots/gloves? never touched your hand to casing ground? Lucky either way
The results from the arc flash study determined what levels of PPE were required, but most of them fail to cover "when covers are removed"

If you didn't have class 0 gloves on, while working in a live 480 cubicle ......I'll stop there
you know you missed the first step of hot-cold-hot check, let alone a clearance on the equipment(which sounds like it was impractical with the temporary feeder)

 

Nope, kneeling on dry concrete. I would have thought that would have been enough ground to get at least a little shock...there was nothing! I always say you never know when your time is up...apparently I wasn't meant to leave a smoking outline on the floor like the cat on "National Lampoons Christmas Vacation" did
Thanks guys, appreciate the comments. Feeling pretty grateful here tonight...

 

Just curious is there a set of safe work practices in place to prevent this, driven by your employer? - and I know we don't all always follow the rules.

It woke you up obviously, but if something didn't come of it as a learning moment for the safety culture at your employer???

 

Bare hand on metal knife man...OK boots...cotton "mechanics pants" kneeling on concrete...I can explain it...the Grace of God!
When I am out riding I always try to remember the old saying "Don't ride faster than your guardian angels can fly"...not sure how that applys to electricians...maybe "know what voltage your guardian angels are rated for"? (and then follow procedures anyways!)

 

Wow. Glad your okay man.

 

Yeah they are pretty good with the safety stuff, this one was all on me. They however are not "safety nazis".
I worked at a place like that in the past...it was insane...common sense right out the window. Like require wearing the "full monty" of burn gear and then write you up when you heat stroke out working in 130* environment...

 

Understood.

 

Double check, double check.
One way we try to prevent disasters in the medical world is by having a second person ck, I know that isn't reasonable in the other work places, but your risk are high there also.