Arc Flash Reduction Maintenance Switch
Arc Flash Reduction Maintenance Switch
(OP)
We have a project where we will be installing a new Eaton Magnum DS Low Voltage Switchgear with an arc flash reduction maintenance switch.
1. Does the maintenance switch set the main breakers to their lowest settings to reduce arc flash hazard while working on the gear?
2. If so, should the arc flash label posted on the gear be based on the settings when the maintenance switch has been switche? Or should the label assume the switch hasn't been activated?
Thanks for the help all.
DJR
1. Does the maintenance switch set the main breakers to their lowest settings to reduce arc flash hazard while working on the gear?
2. If so, should the arc flash label posted on the gear be based on the settings when the maintenance switch has been switche? Or should the label assume the switch hasn't been activated?
Thanks for the help all.
DJR






RE: Arc Flash Reduction Maintenance Switch
2. Good question. The standards do not address this. My recommendation is to use a label based on the maintenance mode being OFF, since this will be the worst case. The effect of the maintenance mode can (and should) be covered in the required Energized Work Permit. If you base the label on the use of the Maintenance Mode, this needs to be very clearly called out on the label.
RE: Arc Flash Reduction Maintenance Switch
RE: Arc Flash Reduction Maintenance Switch
RE: Arc Flash Reduction Maintenance Switch
If you have two label, and an unqualified worker does not understand the meanings, then the fact that there is potential confusion can lead to an unsafe situation.
"You measure the size of the accomplishment by the obstacles you had to overcome to reach your goals" -- Booker T. Washington
RE: Arc Flash Reduction Maintenance Switch
RE: Arc Flash Reduction Maintenance Switch
RE: Arc Flash Reduction Maintenance Switch
I think you all have very good points, and I feel the topic could be argued to eternity... I guess no matter what, it falls on the worker to read labels prior to working and to follow procedures (and hopefully the employer has put in place good maintenance procedures).
Hamburger,
Light sensor to detect an arc event? I am failing to grasp what you mean by this?
DJR
RE: Arc Flash Reduction Maintenance Switch
RE: Arc Flash Reduction Maintenance Switch
As for the stickers, I met a poor USB gear wearing 4 stickers, with categories going from 1 to 4. Seriously... I prefer the worst case scenario and put only one label.
Bob
RE: Arc Flash Reduction Maintenance Switch
RE: Arc Flash Reduction Maintenance Switch
RE: Arc Flash Reduction Maintenance Switch
RE: Arc Flash Reduction Maintenance Switch
RE: Arc Flash Reduction Maintenance Switch
It is a fiber optic sensor as mentioned above. Schweitzer has been pushing their sel-751a which has it. If you want to read about it, look up the ieee pes magazine issue from 2011 that focuses on arc flash. There they compare a bunch of different methods for mitigation. The one I always thought was odd but I think it was the quickest was to crowbar the 3 phases to extiguish the arc.
RE: Arc Flash Reduction Maintenance Switch
Scenario 1:
Company uses worst case labeling. A qualified worker dons PPE per the label prior to interacting with the circuit. Worker puts upstream device in maintenance mode significantly reducing IE from that shown on the label. Result: Possible injury due to unnecessary restriction of movement, sight, or overheating from oversized PPE, and violation of 70E 130.7(C) (9)(f)
Scenario 2:
Company uses worst case labeling. A qualified worker dons PPE per the label prior to an interacting with the circuit. Although provided, worker fails to put upstream device in maintenance mode. Although dressed for the potential IE, worker is still subjected to unnecessary restriction of movement, sight, or overheating; as well as being exposed to a higher than necessary potential IE. All these unnecessary risks due to the failure to use maintenance mode and use properly selected PPE for the task.
Scenario 3:
Company uses worst case labeling. A qualified worker ignores the label and instead goes to the book to select PPE for use during maintenance mode per company policy. Worker puts upstream device in maintenance mode significantly reducing IE from that shown on the label. Worker is not unnecessarily exposed to potential IE or the hazard of using oversized PPE for the task. The apprentice watching all of this is taught that labels are useless and should be ignored.
RE: Arc Flash Reduction Maintenance Switch
What about the scenario where an Energized Work Permit is created, as required by NFPA 70E, and it specifies use of Maintenance Mode for this task and list the appropriate and correct PPE - and everyone live happily ever after?
This doesn't seem relevant to the question at hand.
The argument that wearing PPE creates additional safety hazards has always been popular with those who are looking for reasons to not wear it. It can be a valid concern, depending the equipment, the location and the task to be performed, but in general it is very over-used IMO.
I still prefer to label for the worst-case, but I recognize that there are other valid approaches. There are many roads to Dublin. And wearing any PPE is better than wearing none.
RE: Arc Flash Reduction Maintenance Switch
Thanks for seeing my point. I was responding to Dandel.