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 Post subject: Racking out always required for LO/TO?
PostPosted: Thu Dec 05, 2013 11:18 am 

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We had a debate in a recent electrical safety meeting about whether or not it is required to always rack out a breaker for LO/TO (presuming, of course, that the breaker is a draw-out type). While we all agree that it is 100% required to open AND rack out such a breaker for the purpose of establishing an electrically safe working condition, the debate centered around those instances where an electrically safe working condition is not required (no electrical work is to be performed).

An example of such a situation would be when working on rotating equipment fed by a motor, but NOT working on the motor's leads or being exposed to them. My initial thought was that the breaker should absolutely be racked out since that's the safest way to make sure the motor would not be re-started accidentally. However, racking out the breaker adds a significant amount of risk to the activity. Is it prudent to add this risk to this activity? If the breaker is opened and locked, followed by an attempt to start the motor, isn't that enough protection for workers who are only working on the mechanical equipment driven by the motor? I know that sentence sounds wrong ("isn't that enough protection..."), but given the fact that a significant risk would need to be taken in order to add more protection, what do you all think?


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PostPosted: Thu Dec 05, 2013 12:39 pm 
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BSayl wrote:
We had a debate in a recent electrical safety meeting about whether or not it is required to always rack out a breaker for LO/TO (presuming, of course, that the breaker is a draw-out type). While we all agree that it is 100% required to open AND rack out such a breaker for the purpose of establishing an electrically safe working condition, the debate centered around those instances where an electrically safe working condition is not required (no electrical work is to be performed).

An example of such a situation would be when working on rotating equipment fed by a motor, but NOT working on the motor's leads or being exposed to them. My initial thought was that the breaker should absolutely be racked out since that's the safest way to make sure the motor would not be re-started accidentally. However, racking out the breaker adds a significant amount of risk to the activity. Is it prudent to add this risk to this activity? If the breaker is opened and locked, followed by an attempt to start the motor, isn't that enough protection for workers who are only working on the mechanical equipment driven by the motor? I know that sentence sounds wrong ("isn't that enough protection..."), but given the fact that a significant risk would need to be taken in order to add more protection, what do you all think?


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PostPosted: Thu Dec 05, 2013 12:46 pm 
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I do not agree it is required to rack the breaker out for an electrically safe work condition. For example, if the breaker feeds a motor and you are going to unwire the motor then breaker can be opened and locked, the same as you would do for a MCC bucket. We don't pull the bucket out of the MCC. What is the difference?


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PostPosted: Thu Dec 05, 2013 5:00 pm 
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I guess this is a fine line here. For instance, if you are not working on the motor but rather the pump that is turned by the motor why wouldn't you rack out the the breaker to the disconnect position on a 4150V system? How else to you guarantee that all sources of energy have been removed?
It would help to know what voltage level we are talking about? I myself am a fan of having a visible break wherever possible and grounding.

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PostPosted: Thu Dec 05, 2013 5:06 pm 
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OSHA has SEVERAL subchapters with slightly different rules for loto, so it is critically important to understand what set of rules you are talking about. Among others, 1926 (construction) requires tagging but not necessarily locks. Subchapter J (1910.147) which is the general lockout procedure for mechanical work requires that the mechanism that is locked out requires preventing all sources of hazardous energy from being released and the mechanism generally requires a lock to do so although there are a few narrow exceptions. However there is no visible break requirement at all. Locking out a molded case breaker suffices. Subchapter O does not require locking at all and various safety interlock systems are sufficeny but this is only available to nonmaintenance activities and requires establishing procedures. Subchapter R has multiple types of lockout procedures for utilities including tags only and what can only be described as control-room only procedures in various sections. Subchapter S is specific to electrical utilization equipment. It requires the same kind of lock as subchapter J. It requires visual verification if the mechanism is a visible break type, but does NOT require a visible break disconnect. Opening and locking out a breaker is sufficent by itself, regardless of whether it is draw out switchgear or a molded case breaker where "racking out" would require a lot of disassembly with attendant arc flash risks that the EEWP requiremeny is specifically designed to prevent. All of these are available directly from [url="http://www.osha.gov"]www.osha.gov[/url] if you go into the regulations tab, and they are fairly readable. I would caution you to create a spreadsheet (I have don't have mine anymore) and copy/paste each paragraph onto a separate row with the different subchapters as columns when you read it because it is very easy to mix up different subchapters since even some wording is very similar. So in summary for general nonelectrical maintenance the visible break rule is not there. Under the electrical regulation the visible break must be verified visually if you have one, but it definitely not required to have one. Whether or not you need locks, tags, or both depends on whether it is a construction, utilization, or distribution lockout, and also on equipment design, and sometimes the type of procedure. Many companies get this wrong by using only one of the regulations (usually 1910.147) and are not aware of any others. It does not help that OSHA's own training material also frequently makes a 'single regulation' assumption.


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PostPosted: Sat Dec 07, 2013 12:22 pm 
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Trying to find where subchapter S requires the visual break verified. Can someone point it out?

Tx


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PostPosted: Sun Dec 08, 2013 7:38 am 
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I just rechecked myself and misstated what is in 1910.331-335. You are correct, no visible break verification requirement in Subchapter S. I usually tend to think of Subchapter S as synonymous with 70E-120 since OSHA adopted the verbiage in 70E several years ago and that is essentially what 1910.331-335 is.

Relevant sections:
1910.333(b)(2): While any employee is exposed to contact with parts of fixed electric equipment or circuits which have been deenergized, the circuits energizing the parts shall be locked out or tagged or both in accordance with the requirements of this paragraph....
Note: Permanent wiring only. Temporary wiring, cord-and-plug, etc., does not fall under this unlike 70E which even used to have a complete separate rule for cord-and-plug.

1910.333(b)(2)(ii)(B): The circuits and equipment to be worked on shall be disconnected from all electric energy sources. Control circuit devices, such as push buttons, selector switches, and interlocks, may not be used as the sole means for deenergizing circuits or equipment. Interlocks for electric equipment may not be used as a substitute for lockout and tagging procedures.
Note: "Control circuit devices" requirement is very similar to the requirement in 1910.147. This has been widely interpreted to imply that the disconnect device must be mechanical. One can argue about the difference between a mechanical linkage and an electric/pneumatic/hydraulic "pilot" being not any different but I digress. A molded case breaker has long been considered acceptable as long as the handle can be locked out. There are no user serviceable parts for most MCCB's and thus the contacts will never be visible in any way.

1910.333(b)(2)(iii)(A): A lock and a tag shall be placed on each disconnecting means used to deenergize circuits and equipment on which work is to be performed, except as provided in paragraphs (b)(2)(iii)(C) and (b)(2)(iii)(E) of this section. The lock shall be attached so as to prevent persons from operating the disconnecting means unless they resort to undue force or the use of tools.
Note: There are exceptions for locks without tags as well as tags without locks.

1910.333(b)(2)(iv)(A); A qualified person shall operate the equipment operating controls or otherwise verify that the equipment cannot be restarted.
Note: The "otherwise verify" clause could be interpreted to refer to visual verification of a visible break disconnect device, but does not have to be.

1910.333(b)(2)(iv)(B): A qualified person shall use test equipment to test the circuit elements and electrical parts of equipment to which employees will be exposed and shall verify that the circuit elements and equipment parts are deenergized. The test shall also determine if any energized condition exists as a result of inadvertently induced voltage or unrelated voltage backfeed even though specific parts of the circuit have been deenergized and presumed to be safe. If the circuit to be tested is over 600 volts, nominal, the test equipment shall be checked for proper operation immediately after this test.
Note: This is testing for absence of voltage with equipment. Visual verification is not enough to test for induced or unrelated voltage backfeed.

The visible break requirement is in NEC 225.51 which requires one for feeders to a building in circuits rated over 600 volts where either an oil switch or a circuit breaker is used as the building disconnecting means, except if the disconnecting means is switchgear. This requirement is opposite what the original poster was describing which is clearly stating that switchgear is in use, and that is precisely where NEC has an exception. The exception is tough to read but essentially acknowledges that the cell itself in drawout gear suffices to meet the visible break requirement.

NEC specifies installation requirements. With very small and rare exceptions, NEC does not dictate work methods. That is left to NFPA 70B (maintenance) or 70E (safety).


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PostPosted: Mon Dec 09, 2013 7:18 am 

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Thanks for the feedback.

@wbd: The reason I wouldn't rack out the breaker is that the very act of racking out (and back in) the breaker involves a significant hazard. If all of my equipment had remote racking capability, I'd be more inclined to rack out, but that's a whole separate can of worms I don't want to open as part of this discussion.

@PaulEngr: Thanks for the detailed response. I did double-check OSHA regs and Subchapter J would be applicable in the cases I'm considering. Thank you for pointing me in that direction. As you stated, there is no visual break requirement there. Nor is there such a requirement in Subchapter S.

70E-120.1(3) includes the visual break requirement as part of "establishing an electrically safe work condition". However, establishing an electrically safe work condition is required in situations described by 70E-130, ("work involving electrical hazards") where electrical conductors or circuit parts might be exposed. My scenario specifically does not involve the possibility of exposing conductors so this would not apply.

So I believe OSHA Subchapter J (1910.147) is the applicable standard and therefore racking the breaker out would not be required.

Now, the act of opening/closing and/or racking in/out is covered by 70E-130.2. The exception in 130.2 states that the breaker does not need to be put into an ESWP in order to open/close or rack it, but that only means that I don't need to open/rack everything upstream of the breaker in question. So, I would be performing energized work by opening the energized breaker, and would be performing additional energized work by racking the breaker on/off of an energized bus. While I don't believe the "Greater Hazard" standard of 70E-130.2(A)(1) technically applies here, the spirit of it would, which is to say that it would tell you NOT to perform energized work that is not absolutely required. Wouldn't racking the breaker in this case be considered energized work that's not absolutely required?


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PostPosted: Mon Dec 09, 2013 7:54 am 
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I assume that you have a high AFH on the bus where the breakers are. The majority my background is from electric utility work and on overhead lines/substations a visible break is require. The utilities I worked for also carried this concept into the generating stations, so breakers had to be racked out to work on equipment.

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PostPosted: Mon Dec 09, 2013 8:19 am 
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PostPosted: Mon Dec 09, 2013 8:27 am 
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Just to provide an additional information for your discussion-
On some older designs of LVPCB in our facilty, I have noticed that even when the breaker is locked (tab pulled out, lock applied), the "trip free" condition on these older units allows the closing mechanism to actually close the contacts, but the operator immediately trips the breaker. So we have some units feeding motors, the motor momentarily energizes. In the case where we are working on these units (motor or pump), we have decided to rack the breaker out, also gives us a visible break.
On most or all late model breakers, the design of the breaker prevents the breaker closing mechanism from actuation when the breaker is locked.


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PostPosted: Mon Dec 09, 2013 12:09 pm 

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Good point about the trip-free design. Our breakers are truly trip-free, so that is not a concern for us.


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PostPosted: Mon Dec 09, 2013 3:11 pm 

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The generalised approach to Hazardous Energy Control that we follow is ISOLATE > PROVE > SECURE. This is the same regardless of whether contact is made with electrical conductors, although test-before-touch additionally applies to electrical contact.
Hence after opening the circuit breaker there is a need to prove that the isolation is effective. There are various ways of achieving this depending on the circumstances. With a rackable circuit breaker, racking it out satisfies the proving step. If it is not racked out then there needs to be some other method applied to prove the isolation.


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PostPosted: Mon Dec 09, 2013 9:21 pm 
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A couple of mistakes here. 70E-120 requires visual verification of visible break disconnects ONLY if one is present. It is not required if there is no visible break device. For instance this would be true with 15 A breakers in a lighting panel. Second, do NOT confuse arc flash and shock hazards. There is no shock hazard if there are no exposed conductors. There may be an arc flash hazard if the employee is interacting with the equipment in such a way that it can cause an arcing fault. This is intended in the realistic and not absolute meaning. For instance opening and closing breakers would not normallu cause an arcing fault in an of themselves. If neither hazard is present, then this would not fall under the EEWP requirement. The testing for absence of voltage would fall under the 130.2 EEWP clause, except that it falls under the diagnostic work exception so that an EEWP is not required for the purpose of establishing an electrically safe working condition. Racking is a bit different. Even with very old gear where you have to take the cover off, it still does not count as exposed because the definition of exposed is a limited sense in that the consideration is iNADVERTENT contact, not someone doing something with a purposeful death wish. However arcing faults can and do occur with draw out gear with alarming likelihood, roughly 80% more likely to fail compared to the breaker itself. Still, my interpretation of the 130.2 exception if it makes any sense at all is that racking for the purpose of de-energizing/re-energizing would be exempted. This exception was introduced when the Code was reorganized. Previously article 110 referred to article 110 for de-energized work and 130 for energized work. However a lot of hazard analysis material was also in article 130 so the material in article 110 was moved to 130 and it appears the exception was added to clear the way for work falling under article 120. I do not believe it was only done to eliminate the catch 22 issue.


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PostPosted: Mon Dec 16, 2013 7:01 am 
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Just opening a breaker and locking it out relies on an INTERLOCK to prevent it from closing in most designs. Therefore most companies require the breaker to be racked out for a LOTO.


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