Working in a live panel

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I was working on a hot panel at a huge plant (Sperry Rand turned Honeywell) in the 80's. There was this huge glassed in room with tons of those big old computers with what looked like huge reel to reel tapes on them and lots of people in white lab coats inside.

My boss, his boss and a couple of engineers from Sperry were there to supervise. I removed the panel cover, no problem. I removed the dead front, BIG problem.

A loaded three phase breaker made a slight arcing noise and within ten seconds I had about twenty of those rocket scientists converging in the room an I am the only one with tools on.

Apparently they lost a bit of data.:D
 
220/221 said:
1. Troubleshooting is difficult with the power off.
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True, but most of the 'work' I saw earlier seemed to be adding conductors and pushing fish tapes, etc. These seem like two different 'work' issues.

2. To simply add a circuit in an occupied building would require after hours work, generator power and possibly an extensive set up of lights.
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I wonder what happens in the building if PoCo drops power for 15 minutes?
 
Pierre C Belarge said:
In order to help some to understand that safety really is important, I am going to relate a story about my recent (2 weeks ago) panel work.

I was hired to perform some testing in a small (2-800 amp) gears. I had all of the good stuff, blankets, tools, gloves, protective equipment, etc.... The power was to stay on as the testing was for voltage and current. That is very hard to test if the power is turned off :D


Well I do the whole set up thing, and the contractor thinks I am nuts. I will not even let his electrician near the work, as he has no protective equipment.
As I am putting on my gloves, I remember to remove my wedding ring. I put it in the pocket of my Fluke tool bag.
About 3 hours later, I am finished. I am putting all of my tools away and I am now looking for my ring, of course I forgot where I left it and in a small panic have I enlisted the factory people to help me scour the floors for the "missing" ring. Finally after going over in my mind how to fabricate a story to tell my wife I lost the ring, I remembered where the ring was.
Moral of the story. Put the ring somewhere where you will remember and do not make an a$$ out of yourself. Wait, I forgot...yes, safety is that important.:wink:
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Electrons may or may not kill me. Losing my wedding ring would pretty much guarantee that the kids would be arguing in probate over who gets my stuff!!
 
While it is obvious that we have very few good reason to work in a hot panel, and one great reason not to, I still find myself doing it from time to time.

I can add only one thing to the cautions already posted. Plan your work. Look over everything and decide what you are going to do and how, so that your short time in the live panel is deliberate and effective.

However, it is far better to kill the power than yourself.
 
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More often than not a Poco will drop power if you plan ahead. Unfortunately to many sparkies fold to the pressure and jump in the hot panel to either appease
a client or to make themselves look like THE MAN.
Sadly i know its our job to work em hot sometimes , but its gotta be a last resort , and if you do my suggestion is........NO INTERRUPTIONS NO BODY IN THE ROOM WITH YOU, NO PHONES NO DISTRACTIONS
just my thoughts
 
Do you not have distribution panel assemblies that are designed for live working? Much of my European experience was with data centres, and you dont want to turn them off to install another circuit, but the safely legislation makes it more or less impossible to work live on exposed panels. So... the distribution boards were designed from the start to be worked on live. There were no exposed live bits, the live bars and their connections being fully enclosed. The new MCB plugged in to its slot, and then you slid a thing across, and this slidy thing connected the MCB to the bar. This was the MG IsoBar system. (MG - part of Schneider, who now ownd SquareD) All in full safety.

For switchgear it all has to confoirm to "form 4", which separates stuff into compartments, and again you can do much (but not all) work on a live panel in full safety.
 
hot panelboards

hot panelboards

I work in hot panels and disconnects all the time. Wear PPE, use insulated tools, tape up what you don't want to touch, go slow and THINK, wear rubber-soled shoes, and TURN OFF THE CELL PHONE!! On one job I was working with my hands an inch from hot mains when my phone rang. Even though I let the call go to voice mail I jumped, and dang near got a 240VAC, 200A joy buzz. Not my comfort zone! I put it on vibe now when I work hot.
 
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