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Hot Removal and intallation of buss plugs
- Thread starter mmandilk
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charlie tuna
Senior Member
- Location
- Florida
Re: Hot Removal and intallation of buss plugs
shut it down!!! i have done them hot in the past but too many reports of injuries and deaths have changed my mind!! years ago i had a building ask me to install a 800 amp tap on a 4000 amp - 480 volt bus. no problem except i needed to know the bus configuration to order it from i.t.e.. i asked the i.t.e. rep if there was a problem with removing the bus tap access plate while it was energized? "no problem" he said!!! well, "normally" there isn't - except the metal plate that the access plate screw engages into was loose from the normal "spot welded" position.
when we removed the screw, the plate fell inside the bus and grounded out causing a major ark flash and tripping the bus out on ground fault! thank god we were not burnt too bad ---splattered with hot metal and the bus was not damaged!!! we have removed damaged bus that the insulation was damaged or burnt up in the tap area. not visible from the tap access hole. if someone tried to install a tap in this area and disturb the bus ---they would probibly have a phase to phase explosion!!! bus can look brand new on the outside with the inside damaged! remember, bus duct is one of the wiring methods we deal with that does not contain the ark within it's enclosure when it fails!!! and i tell building engineers "you can pi$$ on it and blow it up" it don't take much moisture to explode!!!
shut it down!!! i have done them hot in the past but too many reports of injuries and deaths have changed my mind!! years ago i had a building ask me to install a 800 amp tap on a 4000 amp - 480 volt bus. no problem except i needed to know the bus configuration to order it from i.t.e.. i asked the i.t.e. rep if there was a problem with removing the bus tap access plate while it was energized? "no problem" he said!!! well, "normally" there isn't - except the metal plate that the access plate screw engages into was loose from the normal "spot welded" position.
when we removed the screw, the plate fell inside the bus and grounded out causing a major ark flash and tripping the bus out on ground fault! thank god we were not burnt too bad ---splattered with hot metal and the bus was not damaged!!! we have removed damaged bus that the insulation was damaged or burnt up in the tap area. not visible from the tap access hole. if someone tried to install a tap in this area and disturb the bus ---they would probibly have a phase to phase explosion!!! bus can look brand new on the outside with the inside damaged! remember, bus duct is one of the wiring methods we deal with that does not contain the ark within it's enclosure when it fails!!! and i tell building engineers "you can pi$$ on it and blow it up" it don't take much moisture to explode!!!
crossman
Senior Member
- Location
- Southeast Texas
Re: Hot Removal and intallation of buss plugs
I'm with you guys on this one.
Years ago, we used to do tons of hot work on the power gear for a major communications company. They would have us do the work in the middle of the night when the load was the lowest... in case we blew something up, they could switch to battery back-up and not drain the batteries down as quickly as in peak hours. I used to think I was a bada** electrician because I could tap hot busses, put on lugs, bus fingers, the works, all while energized.
Safety glasses, hot gloves, taped up wrenches, and a couple of rubber blankets.
I cannot believe how stupid I was back then. And I give thanks that I am still in one piece. All it takes is one loose screw, something to come loose and fall in the buss, something not even related to what you are doing... kinda like russian roulette.
Never again.
I'm with you guys on this one.
Years ago, we used to do tons of hot work on the power gear for a major communications company. They would have us do the work in the middle of the night when the load was the lowest... in case we blew something up, they could switch to battery back-up and not drain the batteries down as quickly as in peak hours. I used to think I was a bada** electrician because I could tap hot busses, put on lugs, bus fingers, the works, all while energized.
Safety glasses, hot gloves, taped up wrenches, and a couple of rubber blankets.
I cannot believe how stupid I was back then. And I give thanks that I am still in one piece. All it takes is one loose screw, something to come loose and fall in the buss, something not even related to what you are doing... kinda like russian roulette.
Never again.
Re: Hot Removal and intallation of buss plugs
Thanks I agree totally we are all Lucky. I still was wondering if there is a legal staement in 70 E to support the "Shall not be energized" idea. A co worker found this in 70E:
ARTICLE 130 Working On or Near Live Parts
130.1 Justification for Work.
Live parts to which an employee might be exposed shall be put into an electrically safe work condition before an employee works on or near them, unless the employer can demonstrate that deenergizing introduces additional or increased hazards or is infeasible due to equipment design or operational limitations.
This doesn't include troubleshooting.
Thanks I agree totally we are all Lucky. I still was wondering if there is a legal staement in 70 E to support the "Shall not be energized" idea. A co worker found this in 70E:
ARTICLE 130 Working On or Near Live Parts
130.1 Justification for Work.
Live parts to which an employee might be exposed shall be put into an electrically safe work condition before an employee works on or near them, unless the employer can demonstrate that deenergizing introduces additional or increased hazards or is infeasible due to equipment design or operational limitations.
This doesn't include troubleshooting.
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