live work

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jsilva

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Rhode Island
There is an article on the NEC that allows an electrician in some instance to do work on a live circuit, because by isolating the power will cause interruption to a process. If am right please let me know the article #. Thanks guys!
 

iwire

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Location
Massachusetts
There is an article on the NEC that allows an electrician in some instance to do work on a live circuit, because by isolating the power will cause interruption to a process. If am right please let me know the article #. Thanks guys!
It is not in the NEC it is OSHA.

1910.333(a)(1)

"Deenergized parts." Live parts to which an employee may be exposed shall be deenergized before the employee works on or near them, unless the employer can demonstrate that deenergizing introduces additional or increased hazards or is infeasible due to equipment design or operational limitations. Live parts that operate at less than 50 volts to ground need not be deenergized if there will be no increased exposure to electrical burns or to explosion due to electric arcs.

Note 1: Examples of increased or additional hazards include interruption of life support equipment, deactivation of emergency alarm systems, shutdown of hazardous location ventilation equipment, or removal of illumination for an area.

Note 2: Examples of work that may be performed on or near energized circuit parts because of infeasibility due to equipment design or operational limitations include testing of electric circuits that can only be performed with the circuit energized and work on circuits that form an integral part of a continuous industrial process in a chemical plant that would otherwise need to be completely shut down in order to permit work on one circuit or piece of equipment.

Note 3: Work on or near deenergized parts is covered by paragraph (b) of this section.
First if you can meet one of the items in Note 1 you could then perform only the things listed in Note 2.

You are basically limited to testing and troubleshooting, no adding circuits or breakers etc.

And of course if you are allowed to work live you need to be trained and have the proper protective equipment.
 

eric9822

Senior Member
Location
Camarillo, CA
There is an article on the NEC that allows an electrician in some instance to do work on a live circuit, because by isolating the power will cause interruption to a process. If am right please let me know the article #. Thanks guys!
Read the 70E section very carefully. It does not say you can work live if you are going to interrupt a process. It says you can work live if interrupting power will cause a larger hazard. I don't have my 70E with me to quote the actual section. For the most part there are very very few circumstances where live work is justifiable.
 

Volta

Senior Member
Location
Columbus, Ohio
Read the 70E section very carefully. It does not say you can work live if you are going to interrupt a process. It says you can work live if interrupting power will cause a larger hazard. I don't have my 70E with me to quote the actual section. For the most part there are very very few circumstances where live work is justifiable.
You're right, generally. However if you can demonstrate that a deenergized state is infeasible due to operational limitations it is permitted.
NFPA70E 130.1(A)(2) 2009.
 

eric9822

Senior Member
Location
Camarillo, CA
You're right, generally. However if you can demonstrate that a deenergized state is infeasible due to operational limitations it is permitted.
NFPA70E 130.1(A)(2) 2009.
A lot of people interpret infeasible to mean inconvenient or expensive. In most industries there is no justification.
 

Volta

Senior Member
Location
Columbus, Ohio
Yeah, I think we need to interpret it that way or else they would have said impossible.

What would you consider an operational limitation?

Voltage, current, operating temperature come to mind, of course.

What about a large 24-hour processing facility that would need to be be shut-down to work in a panel to add a circuit?
 

iwire

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Location
Massachusetts
What about a large 24-hour processing facility that would need to be be shut-down to work in a panel to add a circuit?
IMO you would have to shut down as much as it took to make it 'dead work'

The following is an OSHA Standard Interpretation.

December 19, 2006

Mr. Alan E. Scales
Safety Department
Fairchild Semiconductor International
333 Western Avenue
MS 01-31
Portland, ME 04106

Dear Mr. Scales:

Thank you for your June 6, 2006, letter to the Occupational Safety and Health Administration's (OSHA's) Directorate of Enforcement Programs. You had questions regarding OSHA's Selection and use of work practices standard, 29 CFR 1910.333, as it relates to "continuous industrial processes" and the infeasibility of de-energizing equipment under certain circumstances. Your paraphrased scenario, question, and our response follow.

Scenario: The manufacturing of our products involves many discrete pieces of equipment whose individual processes are part of the overall manufacture of integrated circuit components. For example, we have ten pieces of manufacturing equipment fed out of a 480-volt three-phase panel. A new project requires that additional feeders and a 225-ampere circuit breaker be added to the panel to supply a new piece of equipment. To perform the work in a de-energized state, it requires the power to the panel must be disconnected and appropriate LOTO devices applied. This activity would result in the shutdown of the ten pieces of equipment, causing a significant interruption to our ability to manufacture integrated circuits.

Question: Is the panel considered part of a "continuous industrial process," thus allowing the work to be performed while the panel was energized using electrical safe work practices, as per Note 2 in ?1910.333(a)(1)?

Response: It appears that your panel is not part of a "continuous industrial process." The term "continuous industrial process" was derived from its use in the National Electrical Code (NEC). In the NEC "continuous industrial process" is used in the context of situations where the orderly shut down of integrated processes and equipment would introduce additional or increased hazards.1 Therefore, to qualify for the exception found in Note 2 of ?1910.333(a)(1), the employer must, on a case-by-case basis, determine if the orderly shutdown of the related equipment (including the panel) and processes would introduce additional or increased hazards. If so, then the employer may perform the work using the electrical safe work practices found in ??1910.331-1910.335, including, but not limited to, insulated tools, shields, barrier, and personal protective equipment. If the orderly shutdown of the related equipment and processes would not introduce additional or increased hazards, but merely alter or interrupt production, then the de-energization of the equipment would be considered feasible, and the exception found in Note 2 of ?1910.333(a)(1) would not apply. Based on the limited information you provided, it does not appear that de-energization of the panel in question would introduce additional or increased hazards.

Thank you for your interest in occupational safety and health. We hope you find this information helpful. OSHA requirements are set by statute, standards, and regulations. Our interpretation letters explain these requirements and how they apply to particular circumstances, but they cannot create additional employer obligations. This letter constitutes OSHA's interpretation of the requirements discussed. Note that our enforcement guidance may be affected by changes to OSHA rules. Also, from time to time we update our guidance in response to new information. To keep apprised of such developments, you can consult OSHA's website at http://www.osha.gov. If you have any further questions, please feel free to contact the Office of General Industry Enforcement at (202) 693-1850.

Sincerely,



Richard E. Fairfax, Director
Directorate of Enforcement Programs
From here "Continuous industrial processes" and the infeasibility of de-energizing equipment under 29 CFR 1910.333.
 
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eric9822

Senior Member
Location
Camarillo, CA
Yeah, I think we need to interpret it that way or else they would have said impossible.

What would you consider an operational limitation?

Voltage, current, operating temperature come to mind, of course.

What about a large 24-hour processing facility that would need to be be shut-down to work in a panel to add a circuit?
Check out IWire's post. Infeasible and impossible are fairly close to the same same meaning. I work in a 24-hour facility and up until a few years ago it was very common to perform live work even when we could have easily planned a little better and shut down specific pieces of equipment. We have not performed live work in a few years now and we have idled significant portions of the site and dozens of employees for hours at a time when work was required. Interestingly enough the most resistance to enforcing the no live work rule came from the electricians and not management.
 
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