Operating a Breaker with Door Open

[acerfootball]

My company is reviewing our Electrical Safety policy and a question regarding the operation of breakers came up. Attached is a picture of the breakers in question(480V, 50A and 70A breakers, Cat. II per 2012 70E). My understanding of 70E(2015) is that "Normal Operation" of equipment shall be permitted when "(3) The equipment doors are closed and secured.". In the picture, clearly I can't operate the breakers with the doors closed so does this mean that the breakers can only be operated when they are de-energized? Meaning I shut down the upstream device, open the door to this panel, close the breaker, close the door, and then turn on the upstream device? If so, the argument was made that circuit breakers' lifespan would be hit if this process became the norm for operating the breakers. I'm not sure I agree with that but I'm 6 months on the job so still learning.

What are you thoughts operating these breakers while following 70E?

 

[zog]

You can operate them with the doors open, you just have to wear the correct PPE. I would suspect that if you did an actual arc flash study instead of using the tables the required PPE would be minimal. (Can't assume that though).

 

[charlie b]

Keep in mind that when you are determining what PPE would be required for this task, the task is not merely operating a breaker handle. You are also reaching past some energized metal parts, and your hand will be close to other energized metal parts as you operate the breaker. So the hazard is not limited to an unlikely arc flash event. It also includes the not-so-unlikely event of inadvertent contact with energized objects.

 

[petersonra]

in your case you probably cannot operate the breakers at all until you turn off the power to the enclosure since you can't work on live equipment (other than some very narrow exceptions), at least if you follow all the riles in 70E.

and once you are inside the cabinet you are exposed to live voltage, short of turning it off first.

I think that a strict reading of the rules would require that you first shut off power to the enclosure. open the door with your suit on, check to make sure power has been removed. then you can do whatever you need to do inside with, or w/o the suit. you can then close the CB, close the door, and turn power back on to the enclosure when you are done.

 

[meternerd]

in your case you probably cannot operate the breakers at all until you turn off the power to the enclosure since you can't work on live equipment (other than some very narrow exceptions), at least if you follow all the riles in 70E.

and once you are inside the cabinet you are exposed to live voltage, short of turning it off first.

I think that a strict reading of the rules would require that you first shut off power to the enclosure. open the door with your suit on, check to make sure power has been removed. then you can do whatever you need to do inside with, or w/o the suit. you can then close the CB, close the door, and turn power back on to the enclosure when you are done.

The pic appears to be a SCADA cabinet. Shutting off the entire cabinet would likely disable numerous devices. If working on only one device it sure would seem overkill to de-energize the entire cabinet. That's also assuming there is only one source. Many MCC SCADA controls have the PLC outputs or associated relays separately powered. Power would likely come from the MCC motor breaker and control power would be via a stepdown control transformer. Quite a project to de-energize every possible source inside the cabinet. Arc flash studies for this type of equipment can be a real nightmare. Most we used were just based on "worst case", meaning overkill. I think appropriate PPE working inside or operating the breaker would make more sense, even though working on small parts becomes a real headache. Also, the upstream breaker may not be designed to be operated as a switch, but rather as a OCPD. I've seen many breakers that fail to reset due to wear from overuse. Just my opinion, though. I'm no safety expert....just an old, retired electrician who has had to see the PPE stuff evolve into a real pain over the years.

 

[wbdvt]

We have run into these cabinets before and the PLC techs generally have not been trained in arc flash and PPE but need to work inside the cabinet. One way of handling this and making it safe is for a qualified electrician to open the cabinet and apply rubber insulating material on any exposed energize components while wearing the proper PPE. Typically this is the main breaker, contactors, small transformer, etc.

 

[cornbread]

Great to see your company asking the question. Having worked on many panels like this I have always considered operation of breakers as part of normal trouble shooting. I'm sure others will disagree. Even if you are using the breaker as a disconnect means you still need to use a meter and proper PPE to make sure the breaker is open. Since we adopted 70E, using the info on the Arc flash labels, it really clear what PPE is required.

 

[acerfootball]

in your case you probably cannot operate the breakers at all until you turn off the power to the enclosure since you can't work on live equipment (other than some very narrow exceptions), at least if you follow all the riles in 70E.

and once you are inside the cabinet you are exposed to live voltage, short of turning it off first.

I think that a strict reading of the rules would require that you first shut off power to the enclosure. open the door with your suit on, check to make sure power has been removed. then you can do whatever you need to do inside with, or w/o the suit. you can then close the CB, close the door, and turn power back on to the enclosure when you are done.

This begs the question how strict does one read the rules of 70E? The other suggestions on this thread seem to violate one or more rules that 70E has. So from an application standpoint of 70E, does one make steps towards full compliance even though true compliance isn't reached? Or does one do everything he can do to ensure full compliance? I imagine many of you have more experience than I do. In your own environments do you make steps towards 70E or follow it to a "T"?

 

[jim dungar]

This begs the question how strict does one read the rules of 70E? The other suggestions on this thread seem to violate one or more rules that 70E has. So from an application standpoint of 70E, does one make steps towards full compliance even though true compliance isn't reached? Or does one do everything he can do to ensure full compliance? I imagine many of you have more experience than I do. In your own environments do you make steps towards 70E or follow it to a "T"?

NFPA 70E 110.1(G) specifically requires that a risk assessment be performed. While it does not provide an actual methodology, the second item it lists is "assess risks". The 70E definition of 'risk assessment' kind of provides the gray area that we do not need to protect against 100% of the remotely possible (e.g. a meteorite strike) dangers in the workplace. Common sense is not outlawed. The concept of risk assessment is extended into the 70E notion of 'normal operation' found in 130.2(A)(4) and 'working while exposed to hazards' in 130.3.

Create a Employee Safe Work Practices program.
Follow all of NFPA70E, do not pick and choose sections.
PPE is the last line of safety, use it properly.