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 Post subject: Bus Duct Plugs
PostPosted: Wed Oct 14, 2009 1:13 pm 
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Joined: Thu Apr 17, 2008 12:36 pm
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Location: Clarksville, Tn
What is the prevailing thought on installing and/or removing a bus plug from a bus duct. Can you do this with the bus duct energized or not? I have seen conflicting statements about this and I don't see where NFPA or OSHA speaks directly to this.


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PostPosted: Sun Oct 18, 2009 7:54 am 
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Location: Lawrenceburg KY
The NFPA 70E section on HRC and PPE speaks to this issue. (If I remember correctly). As you are aware of most busway system IE is very high and work is dangerous in most cases.

I personally recommend in my reports that no one be allowed to plug in 480v type busway busplugs in without a EWP & PPE and the worker is task specific trained on installing busplugs.

I continue to say: Only busplugs <200a may be allowed to be changed with power on the busway. Because, the handling is easier and the chance for an accident is reduced by the ease of installation.
Units >200a requires the busway system to be de-energized.

I believe NFPA HRC for 480v busplug is a 2 or 2* if I remember correctly. With limits on the SCCR.


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PostPosted: Sun Oct 18, 2009 4:47 pm 
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THE CABLE GUY wrote:
The NFPA 70E section on HRC and PPE speaks to this issue. (If I remember correctly).


Correct.

THE CABLE GUY wrote:
I believe NFPA HRC for 480v busplug is a 2 or 2* if I remember correctly. With limits on the SCCR.


HRC 2* for systems up to 65 kA SCC and 0.03 s clearing time, with nominal voltage from 277 to 600 V.


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PostPosted: Thu Jan 07, 2010 8:55 am 
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Location: Bowling Green, KY
Our policy is that unless there is an emergency where de-energizing the bus would cause an endangerment to a life support system or cause a hazard of another kind, (flooding etc). It shall be done with the power in an "electrically safe work condition".
If they want it done "hot" it must be under 200 amps and approved by the safety department, the EE, and the plant manager...and good luck getting those signitures....So we schedule ours in an off shift time. but we do not run "production" so it is easier, and we have a 4 hr. window.


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PostPosted: Fri Apr 16, 2010 12:18 pm 
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We are a production shop . 480 V bus throughout the plant most rated 400 amp . We schedule shutdowns of the machine's if we have to pull or add a bus switch . Doesn't matter if the switch is rated 30 amps or not . We do this during the machinist luch or break . Our management has no problem as long as we schedule this .


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PostPosted: Fri Apr 16, 2010 1:16 pm 
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THE CABLE GUY wrote:
...I personally recommend in my reports that no one be allowed to plug in 480v type busway busplugs in without a EWP & PPE and the worker is task specific trained on installing busplugs...


And the PPE usually needs to include fall protection or a work platform. Not much fun falling off of a 12' step ladder after you've just had a quick snack of molten copper.

davebones wrote:
We are a production shop . 480 V bus throughout the plant most rated 400 amp . We schedule shutdowns of the machine's if we have to pull or add a bus switch . Doesn't matter if the switch is rated 30 amps or not . We do this during the machinist luch or break . Our management has no problem as long as we schedule this .


That's the way to do it. :)


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