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| Arc Flash Labels - How Far? https://brainfiller.com/arcflashforum/viewtopic.php?f=33&t=2401 |
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| Author: | Jim Phillips (brainfiller) [ Sun Aug 26, 2012 2:28 pm ] |
| Post subject: | Arc Flash Labels - How Far? |
How far do you take the arc flash labeling?
There are usually a lot of varied opinions about this one. Let us hear yours. |
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| Author: | Ken Cybart [ Mon Aug 27, 2012 5:56 am ] |
| Post subject: | |
The intent of NEC 110.16 and NFPA 70E is that any equipment over 50 volts that is likely to be opened while energized for examination, adjustment, servicing, or maintenance must be evaluated for arc flash hazards to warn qualified workers and be labeled with the Arc Flash boundary, Voltage, and at least one of the following: (1) Possible incident energy and working distance; (2) Highest Hazard Risk Category; (3) Minimum Arc Rating of PPE: or (4) Required Level of PPE |
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| Author: | Gary B [ Mon Sep 24, 2012 7:06 pm ] |
| Post subject: | |
How many guys work on motor terminal boxes while the motor is running? That is why we generally stop the labels at the MCC. I am aware of one agency that IR scans motor terminals and is interested in labelling the terminal boxes, but that is an exception. |
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| Author: | Ken Cybart [ Mon Sep 24, 2012 7:17 pm ] |
| Post subject: | |
Oftentimes, the Arc Flash incident energy is greater at the motor terminals than at the MCC. The added impedance of the cables lowers the arcing current and slows down the opening time of the breaker or fuse, increasing the possible Arc Flash incident energy at the motor terminals. |
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