Does racking a breaker constitute live work

[jischr]

We have a 480V, 1600 amp breaker that gets racked out when work needs to be performed. It is racked out with a closed front. The act of racking introduces an arc flash/blast hazard.

The switch feeding the breaker is 4160V, 1200 amp, that is not capable of being locked out. So racking out the 4160 switch is the equivalent of lockout.

The debate is that racking the 4160V switch introduces a greater hazard so we are justified in racking out the 480V breaker while the buss is live. As a safety engineer my counter is that the 4160V switch should be be thrown and taggged out; and a person could be station at the switch to prevent actuation until the person working on the breaker is standing in front of them and throws it.

The basic question is, does racking a breaker constitute work with an electrical hazard that requires de-energization to comply with 70E and 1910.333, or is it no different than throwing any other switch at the equivalent voltage?

Thanks

 

[petersonra]

hint.

remote racking the breaker introduces no hazard to the worker at all.

IMO if they are standing within the arc flash zone, while a breaker is being racked it is hazardous and should be treated that way. I think if you look closely NFPA70E treats it this way as well.

the problem with racking is that you are not throwing a switch. you are removing the CB from the bus, and that is not something that the switch is designed to do in an especially safe way.

so either deenergize the power to the breaker first or do it remotely IMO.

I am not sure why you would rack a switch or a CB if it can just be opened to do work downstream. My guess is that any switch that can be opened can be locked out in some way. Build a cover over it if you have to.

I do not believe that merely racking a Cb or switch constitutes proper lockout unless there is some way to lock it in the racked out position.

 

[jim dungar]

The basic question is, does racking a breaker constitute work with an electrical hazard that requires de-energization to comply with 70E and 1910.333, or is it no different than throwing any other switch at the equivalent voltage?

Many experts agree that racking a breaker is probably the most dangerous activity which you can perform.

 

[zog]

We have a 480V, 1600 amp breaker that gets racked out when work needs to be performed. It is racked out with a closed front. The act of racking introduces an arc flash/blast hazard.

The switch feeding the breaker is 4160V, 1200 amp, that is not capable of being locked out. So racking out the 4160 switch is the equivalent of lockout.

You sure the switch can be "racked out"? You mean opened? I also assume there is a transformer between the switch and breaker.

The debate is that racking the 4160V switch introduces a greater hazard so we are justified in racking out the 480V breaker while the buss is live.

Well that depends on the arc flash study results but typically you find larger arc flash hazards on the 480V side than you will on the 4160V side.

As a safety engineer my counter is that the 4160V switch should be be thrown and taggged out; and a person could be station at the switch to prevent actuation until the person working on the breaker is standing in front of them and throws it.

Again depends on your study results but yes typically that is how it is done.

The basic question is, does racking a breaker constitute work with an electrical hazard that requires de-energization to comply with 70E and 1910.333, or is it no different than throwing any other switch at the equivalent voltage?

Racking a breaker is not considered "energized work" per the 70E definitions, so an EEWP is not required. However it does still require the proper PPE to be worn if racking the breaker from inside the AFB. Remote racking devices are an excellent solution to this common issue.

Thanks[/QUOTE]

 

[zog]

Many experts agree that racking a breaker is probably the most dangerous activity which you can perform.

Right, which is why the 70E changed the task tables to HRC 4 for all racking operations regardless of voltage and if the doors are open or closed.

 

[zog]

I am not sure why you would rack a switch or a CB if it can just be opened to do work downstream. My guess is that any switch that can be opened can be locked out in some way. Build a cover over it if you have to.

I do not believe that merely racking a Cb or switch constitutes proper lockout unless there is some way to lock it in the racked out position.

LOTO procedures require visable verification of isolation, you can't see the contacts of a breaker so proper LOTO often requires the brealer to be locked out. In fact, many draw out CB's are designed to only be locked out in the disconnected position.

 

[petersonra]

LOTO procedures require visable verification of isolation, you can't see the contacts of a breaker so proper LOTO often requires the brealer to be locked out. In fact, many draw out CB's are designed to only be locked out in the disconnected position.

How would any CB have visible verification of isolation? You can't see the contacts on any of them. yet it is generally considered acceptable to lock them with the handle in the off position as a lockout means.

 

[zog]

How would any CB have visible verification of isolation? You can't see the contacts on any of them. yet it is generally considered acceptable to lock them with the handle in the off position as a lockout means.

Well most breakers can't close on you if they get a close command, larger draw out breakers should be racked out to provide a visual isolation and to ensure that won't happen. I see locks misapplied on breakers all the time in plants. The specific requirements depend on what safety rules you fall under, NESC requires visiable breaks.

 

[BPoindexter]

Racking a breaker does not constitue "Live Work" per NFPA 70E as far as an Energized Electrical Work Permit is required. However proper PPE (for the level of the available Incident Energy) would need to be worn while performing the racking operation. If the level is too high then remote racking, changing settings on the relay, isolating upstream, etc may be required.

And the 4160 side may in fact be the lesser hazard as it may have lower incident energy available than the 480 side due to the higher current available. All depends on system configuration, protective device settings etc. And yes you can rack on/off a live buss without LOTO on the feed. For example we may have one 480 breaker in a lineup that needs to be racked out and we are certainly not going to shut down the entire lineup to do so unless the IE level is so high that it cannot be done safely or there are no critical loads that would pose a hazard to the process they are part of.

 

[jischr]

Follow-up questions

Follow-up questions

I was working off a 2009 copy and have since acquired a 2012 copy of 70E. It looks like the 130.2 exception allows racking a breaker off a live buss provided everything is in good condition and a risk assessment, aka EEWP, has been performed. Sound correct?

OSHA 1910.333 is pretty much identical to the 2009 NFPA 70E so it doesn?t specifically allow that exception. Both 1910.333 (b) deenergized work and (c) energized work, use the wording ?near enough to them to expose the employee to any electrical hazard they present.? My interpretation is that arc flash from racking a breaker off a live buss in included so racking is subject to 1910.333 (a) - deenergized unless a greater hazard or infeasible.

Since there are no OSHA letters of interpretation on this I am seeking your guidance and expertise before going to the local OSHA compliance specialist. Am I reading more into 1910.333 than OSHA and industry expect? Has this been discussed at electrical safety conferences with a consensus of what has to been done? The only options I see are to deenergize or use a remote to move the employee out of the potential blast area.

Thanks

 

[Fulthrotl]

The only options I see are to deenergize or use a remote to move the employee out of the potential blast area.

two links:

http://www.cbsarcsafe.com/remote-racking-systems.htm

https://www.youtube.com/watch?v=4bBvmPRqfmo

the youtube video is the perennial arc flash poster child.

 

[BPoindexter]

OSHA 1910.333 has to do with exposed live parts and whether or not they are energized. If you are reacking a breaker with the doors closed there are no lived exposed parts. Also you need to look at the definition for work. Is the limited approach boundary being encroached up upon i.e. are there hands, tools etc within that boundary? Also an EEWP is not required to place equipment in an electrically safe status. This includes testing for the presence of voltage. So if I need to place a circuit in an electrically safe status I would not need not need an EEWP to rack out and LOTO the breaker. If this were required then you would need an EEWP to avoid having to use and EEWP.

 

[zog]

I was working off a 2009 copy and have since acquired a 2012 copy of 70E. It looks like the 130.2 exception allows racking a breaker off a live buss provided everything is in good condition and a risk assessment, aka EEWP, has been performed. Sound correct?

OSHA 1910.333 is pretty much identical to the 2009 NFPA 70E so it doesn?t specifically allow that exception. Both 1910.333 (b) deenergized work and (c) energized work, use the wording ?near enough to them to expose the employee to any electrical hazard they present.? My interpretation is that arc flash from racking a breaker off a live buss in included so racking is subject to 1910.333 (a) - deenergized unless a greater hazard or infeasible.

Since there are no OSHA letters of interpretation on this I am seeking your guidance and expertise before going to the local OSHA compliance specialist. Am I reading more into 1910.333 than OSHA and industry expect? Has this been discussed at electrical safety conferences with a consensus of what has to been done? The only options I see are to deenergize or use a remote to move the employee out of the potential blast area.

Thanks

Is it just this one breaker you have concerns about? What type of breaker is it?

 

[jischr]

I am using this as an example of several similar areas where work is not done directly to the circuit but an arc blast hazard is recognized as a hazard as a result of work on the equipment.

 

[zog]

I am using this as an example of several similar areas where work is not done directly to the circuit but an arc blast hazard is recognized as a hazard as a result of work on the equipment.

Trying to lead you in best solution direction, pretty sure you get more expertise than your "local OSHA compliance guy" here. Don't underestimate the experience you will find here, your local OSHA guy likely knows a little bit about everything and is an expert in nothing.

Sounds like remote racking and switching could be your best solution but there are many other mitigation strageties that could be more effective. Knowing your equipment type, a little bit about your facility, and other details is vital to getting any good advice. Earlier you sounded like a light industrial facility, now it sounds like you may be a larger plant. You have yet to tell us but to me it sounds like you are a safety guy trying to figure out these 70E requirements.

Has your facility conducted an arc flash study or are you going off the tables?

 

[John120/240]

Zog, jischr is a Safety Engineer,


click on name & view profile

 

[jischr]

Zog - I'm a safety engineer. The facility started in the 1960's and has been added on at minimal expenditure ever since. The distribution system is a bit of a bowl of spaghetti with equipment replacements done based on parts availability.

About a month ago I introduced plant/site management to the need to deenergize except for diagnostics, increased hazard, increased risk. Their MO up to that point was infeasible equals inconvenient. Our plant EE held a meeting with our primary electrical contractor?s safety director which backed up my position very nicely, at least for me. The one point that the safety director made was that OSHA viewed racking out a breaker as working on live equipment and it needed to be deenergized. That is a big problem from the operations side.

Several of us have surveyed our contacts in local companies and some always deenergize while other usually put the worker in an arc suit. Hence my posting to this forum, what?s the law (OSHA) and what?s good manufacturing practice (NFPA) when is comes to racking a breaker?

 

[zog]

Zog - I'm a safety engineer. The facility started in the 1960's and has been added on at minimal expenditure ever since. The distribution system is a bit of a bowl of spaghetti with equipment replacements done based on parts availability.

About a month ago I introduced plant/site management to the need to deenergize except for diagnostics, increased hazard, increased risk. Their MO up to that point was infeasible equals inconvenient. Our plant EE held a meeting with our primary electrical contractor?s safety director which backed up my position very nicely, at least for me. The one point that the safety director made was that OSHA viewed racking out a breaker as working on live equipment and it needed to be deenergized. That is a big problem from the operations side.

Several of us have surveyed our contacts in local companies and some always deenergize while other usually put the worker in an arc suit. Hence my posting to this forum, what?s the law (OSHA) and what?s good manufacturing practice (NFPA) when is comes to racking a breaker?

Pretty much every industrial facility has been (Or will go) through this same senario. OSHA does not yet directly address this, they use the general duty clause and punt to the 70E as the industry standard, sure you already knew that. The big change in the 2009 70E was making all racking operations HRC 4, doors open or closed. The tables are risk based (Compared to the hazard based arc flash analysis) and racking is about the highest risk task you can do.

Now when you get to the main breaker on the LV side of your transformer (Arc Flash guys refer to this as the blind spot) you often have an even bigger issue, due to very long clearing times you have very large hazard levels (Often >100cal/cm2) and when you combine that with the high risk task of racking breakers you have problems. This is why remote racking has become so popular.

 

[brad9m]

Zog, you forgot to ask if they have any protective relaying! If you have relays on the breakers, it could change the setpoints on the breaker for arc flash conditions. Arc flash detection reduces fault clearing times, thus reducing the potential energy released. This information should be in your arc flash study.

 

[zog]

Zog, you forgot to ask if they have any protective relaying! If you have relays on the breakers, it could change the setpoints on the breaker for arc flash conditions. Arc flash detection reduces fault clearing times, thus reducing the potential energy released. This information should be in your arc flash study.

Not much relays can do for the blind spot on the secoandary of a transformer.