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Bus Duct and Arc Flash Hazard?
https://brainfiller.com/arcflashforum/viewtopic.php?f=12&t=4232		 Page 1 of 1
Author:  arcflashlm1 [ Wed Aug 24, 2016 8:04 am ]
Post subject:  Bus Duct and Arc Flash Hazard?
I was asked to evaluate some "newer" bus duct technology that are finger safe, use a turn and lock connection or similar methods without turning off the power. It seems to do a great job at significantly reducing if not outright eliminating the shock hazard. It also looks like the risk of causing a fault when installing or removing a module is reduced (eliminated?) as it seems it would be very difficult to short line to line or line to ground. Therefore the arc flash risk greatly reduced (eliminated?). Assuming there is > 1.2 cal/cm2 energy available, is there still a arc flash hazard here? Comments on Labeling? PPE?
For example only as there are other manufactures with similar technology. https://www.youtube.com/watch?v=B03Bnhh6w8E
Author:  bbaumer [ Wed Aug 24, 2016 11:23 am ]
Post subject:  Re: Bus Duct and Arc Flash Hazard?
Nothing to do with arc flash but I do have a story.

We have some of that Starline busway in a class/lab where I work (I work at a university). The vendor had to change every breaker in every bus plug as they could not handle motor inrush even sized at 250% of FLA they tripped every time. I don't recall now what exact make/model the breakers were but I do recall the supplier replacing them all.
Author:  PaulEngr [ Wed Aug 24, 2016 6:16 pm ]
Post subject:  Re: Bus Duct and Arc Flash Hazard?
The main reason that you get an arcing fault hazard with bus duct is because the speed of connection/disconnection is driven by human effort. Thus if any mistakes are made and the circuit which is believed to be "open" is in fact actually "closed" you draw an arc and it turns into an arcing fault...and this becomes an arc flash.
Author:  jtinge [ Tue Sep 06, 2016 6:48 am ]
Post subject:  Re: Bus Duct and Arc Flash Hazard?
We are planning to construct a new lab facility in the near future where the design calls for the use of bus duct to allow easy reconfiguration of the circuits in each lab. Our safety program does not permit removing or inserting breakers into an energized bus duct. To satisfy this requirement, we required that the design include a disconnect switch on each section of bus duct in each lab to allow a safe method to de-energize the bus prior to reconfiguring the circuits.
Author:  PaulEngr [ Tue Sep 06, 2016 8:50 am ]
Post subject:  Re: Bus Duct and Arc Flash Hazard?
jtinge wrote:
We are planning to construct a new lab facility in the near future where the design calls for the use of bus duct to allow easy reconfiguration of the circuits in each lab. Our safety program does not permit removing or inserting breakers into an energized bus duct. To satisfy this requirement, we required that the design include a disconnect switch on each section of bus duct in each lab to allow a safe method to de-energize the bus prior to reconfiguring the circuits.


May want to consider Meltrics plugs or Crouse Hinds Arktite connectors or a variety of similar designs. These incorporate some kind of disconnect and a plug so that you have to open the load break disconnect in order to insert or remove the plug and also dead front covers to eliminate exposed energized pins. Then all the cabling in such an environment would be of a temporary design (SO cords). A bus duct system is designed as permanent wiring although obviously with some ability to quickly change it around. Cord-and-plug systems in comparison are by design temporary any flexible systems. The only caveat to plug-and-cord is that you have to protect the cords and that at some point you can go from temporary to permanent wiring where the cords should be replaced with permanent equivalents.
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