We have 12470, 4160 and 480 volt gear in our plant. The breakers can be racked (hand cranked) on and off of the hot buss through a hole in the front cabinet door on the gear without opening the door. The enclosures are NEMA 1. some of the cabinet doors have vent holes next to the hole for the breaker hand crank. The question: Is arc flask gear required when someone is racking in/racking out a breaker when the cabinet door is shut?
Arc Flash Gear
- Thread starter session88
- Start date
- Status
- Location
- Lockport, IL
- Occupation
- Semi-Retired Electrical Engineer
I would say yes. The two most likely times for something to fail within an electrical component are when you turn it on or off, or when a person is interacting with it in some way. Racking a breaker in and out qualifies under both descriptions. That is the time you want the worker to be protected. The amount of personal protective equipment required may be influenced by the fact that the doors are kept closed, and it may be influenced by the existance of holes in the doors. The level of required PPE needs to be placed on a sticker on the board, and needs to be determined by someone qualified to perform the appropriate calculation.
- Location
- Logan, Utah
The answer is definitely YES.
70E requires that all appropriate PPE be worn when racking a breaker in or out whether or not the doors are opened or closed.
Chris
70E requires that all appropriate PPE be worn when racking a breaker in or out whether or not the doors are opened or closed.
Chris
zog
Senior Member
- Location
- Charlotte, NC
Yes, if you are using the tables it is HRC 4 for MV and LV, doors opened or closed. Taht's a 40cal/cm2 suit.
2 ways around this, arc rated switchgear or remote racking. http://www.remoterackingsolutions.com/
Hugh_Hoagland_e-Hazard
Member
- Location
- Louisville, KY
Racking Breakers with Doors Closed
Racking Breakers with Doors Closed
The answers above are mostly right. Doors closed in older gear might not really help you. Some newer gear is an exception.
So there are three answers:
1. IF you are using the NFPA 70E Tables for your OSHA required hazard assessment, the answer is YES. You need a 40 cal/cm2 suit if you meet the fault current and clearing time requirements in the tables.
2. IF you did calculations and have the equipment labeled, use the PPE on the label (which might NOT be an arc flash suit).
3. If the gear meets IEEE C37.20.7, it is "arc resistant" switchgear and is designed to contain the arc flash and arc blast. These types of switchgear would require NO PPE if the doors are closed and properly secured.
4. IF you use a remote racking device and you are out of the calculated arc flash boundary, you will need no arc flash PPE.
Hope this helps.
Racking Breakers with Doors Closed
The answers above are mostly right. Doors closed in older gear might not really help you. Some newer gear is an exception.
So there are three answers:
1. IF you are using the NFPA 70E Tables for your OSHA required hazard assessment, the answer is YES. You need a 40 cal/cm2 suit if you meet the fault current and clearing time requirements in the tables.
2. IF you did calculations and have the equipment labeled, use the PPE on the label (which might NOT be an arc flash suit).
3. If the gear meets IEEE C37.20.7, it is "arc resistant" switchgear and is designed to contain the arc flash and arc blast. These types of switchgear would require NO PPE if the doors are closed and properly secured.
4. IF you use a remote racking device and you are out of the calculated arc flash boundary, you will need no arc flash PPE.
Hope this helps.
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