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In Part 1, we reviewed regulatory requirements, discussed hazards of working on ornear energized electrical equipment (such as shock or arc flash); we now need toreview the protective boundaries.

There are 3 boundaries defined by OSHA and NFPA that pertains to working on ornear energized electrical equipment or circuit parts. We will go into more detail butfor starters remember these boundaries are all defined with an exposed energizedequipment and the proximity to that. If the equipment in question is not exposed(e.g., door opened, cover off) these boundaries do not apply.

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The arc flash boundary is based on the incident energy value. Typically it is the outerboundary but there are circumstances where the distance is less than restrictedapproach. The arc flash boundary is based on risk of burn to employees.

Once inside the arc flash boundary all personnel are required to wear appropriatePPE. The PPE values will be determined by the incident energy. An unqualifiedperson may enter but only if escorted by a qualified electrical worker. Boundariesshall be established by either barricades/tape or by personnel.

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The arc flash protection boundary is not a fixed value for equipment voltagelevels. You will need to know the equipment specifications as outline in theNFPA tables or OSHA 1910.269 appendix E. For example you would need:

Maximum short-circuit current available; maximum fault clearing time;working distance to exposed conductor or circuit part.

An incident energy analysis is conducted for each site. At the outcome of theanalysis you will be given labels for each piece of equipment that contains allthe required information such as; incident energy, PPE requirements, limitedapproach and restricted approach boundaries. Arc flash analyses will bereviewed ever 5 years and some or all of the analyses redone if there havebeen changes that may impact the incident energy levels.

NFPA 70E-2015 requires arc flash analyses on DC energy (prior to this it wasAC only); at this time here is no regulatory requirement for DC.

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Limited approach - An approach limit at a distance from an exposed energizedelectrical conductor or circuit part within which a shock hazard exists.

Unqualified person may enter but only if escorted by qualified electrical worker.Remember – once inside the arc flash boundary you need arc rated PPE inaccordance with incident energy levels.

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An approach limit at a distance from an exposed energized electrical conductor orcircuit part within which there is an increased likelihood ofelectric shock, due to electrical arc-over combined with inadvertent movement, forpersonnel working in close proximity to the energized electrical conductor or circuitpart.

Unqualified person may not enter under any circumstances. Remember – onceinside the arc flash boundary you need arc rated PPE in accordance with incidentenergy levels.

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Limited and restricted approach boundaries are for personal shock protection andcan be found in NFPA 70E. To determine boundaries personnel need to identifysystem nominal voltage and if the system is AC or DC.

This is a limited chart, please review NFPA tables for full list of voltage ranges andboundaries.

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This is a limited chart, please review NFPA tables for full list of voltage ranges andboundaries.

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PPE needs to be appropriate for the incident energy level. Once you determine theincident energy you can go to NFPA 70E tables to determine what PPE is needed orreference site incident energy analysis/labels on equipment.

PPE needs to be arc rated. There is a misconception that flame retardant is ok. FRclothing does not provide the needed protection for the energy given off by an arcfault. Be sure your clothing labels state Arc Rated clothing and level of protection.The clothing value should be in cal/cm².

NFPA no longer allows layering unless the system of layering has been tested as aunit by the manufacturer and documented. This means you can not take a 4 cal/cm²shirt and pants and put on 10 cal/cm² coveralls to get 14 cal/cm². Unless this wastested as a unit you would only be protected up to 10 cal/cm², this is your outerPPE.

If you are working outdoors or in the rain your outer layer needs to be the level ofthe incident energy. All under garments need to be natural fiber and no syntheticclothing allowed.

It should be noted that the PPE levels listed in NFPA 70E, OSHA 1910.269 appendixE and equipment labels are rated to prevent burns greater than 2nd degree over50% or more of the body. You will still be injured but not what is consideredserious.

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Once you have the incident energy you can then use this table to select what leveland type of PPE is required.

The difference with the 2012 edition and 2015 edition is n longer is there a PPEcategory 0 and note the requirement for face shield/hood and hearing protectionfor category 1. This was not required in the 2012 edition unless you were above thePPE category 2.

Also, you’re required to have balaclava for category 2, flash suit hood for category 3as well as arc-rated gloves.

The arc rating for clothing has to at least meet the incident energy level. Remember,layering is not allowed unless the clothing has been tested as a clothing unit.

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It is especially important to ensure that employees do not wearundergarments made from fabrics listed in the table even when the outerlayer is flame resistant or arc rated. These fabrics can melt or ignite easilywhen an electric arc occurs. Logos and name tags made from non-flame-resistant material can adversely affect the arc rating or the flame resistantcharacteristics of arc-rated or flame resistant clothing.

It should be noted that there is a difference between arc rated and flame resistantclothing. Arc-rated fabrics can reduce burn injuries during an arc flash exposure byproviding a thermal barrier between the arc flash and the wearer. Flame resistantclothing does not provide (unless the clothing has arc rated value) the protectionagainst the arc flash energy. All clothing used to protect employees from arc flashand blasts shall be arc rated.

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The one question that comes up most often when discussing rubber gloves and leatherprotectors - do we have to use leather protectors at low voltages?

Protector gloves may be omitted for Class 0 gloves, under limited-use conditions, wheresmall equipment and parts manipulation necessitate unusually high finger dexterity.

But OSHA and NFPA state you should always wear leather protectors. There are tworeasons for leather protectors:1. They protect the rubber gloves from damage. In lieu of using leather protectors at the

lower voltage OSHA state you must have a maintenance and inspection program inplace. It is essential that rubber goods are properly cared for. Before each use,rubber goods should be visually inspected for holes, embedded wires, rips ortears, ozone cutting, UV checking and signs of chemical deterioration. If thereare any defects noted the gloves must be disposed of immediately.

2. Leather protectors are also required by NFPA 70E when working within the arcflash boundary. The leather protectors are listed PPE to protect the employeesfrom arc flash/blast injuries. You will have to determine the incident energy andwhether leather protectors are required.

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You need to ensure you select the right meter for the task. If the meter is notproperly rated for the voltage it could be the cause of an arc fault.

The meter must be rated for the voltage and potential transient voltage that couldoccur. So if you’re testing a 480 volt circuit at minimum, you’ll want a meter ratedfor at least 600 volts. If there is a transient voltage spike and you’re using a 480 voltmeter it could explode causing a phase to phase fault.

Be sure the meter is tested prior to and after each use and calibrated/maintained inaccordance with the manufacturers recommendations.

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One of the important changes to NFPA 70E 2015 edition is the requirement toperform a risk assessment. This is to ensure you have assessed the task and chosenthe most effective/practical controls to manage the risk. This process is similar toother risk assessment initiatives you may have deployed such as job safety analysis.

This should be documented and used as part of the job briefing. According to1910.269 you should be conducting a job briefing for each job.

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The use of the hierarchy of controls can demonstrate that you took the appropriatemeasures utilizing an industry standard methodology. You should always start at thetop and ask if the hazard can be eliminated.

The last resort should always be PPE; yes it works but the risk is still there. There aremany things that can go wrong with the PPE so try and utilize other controls tomanage the risk.

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It is imperative that the meter used in verify absence of voltage is properly working.In order to verify this the qualified electrical worker must properly dress out in arcrated PPE and treat the circuit as live until proven dead.

• Test the meter on a known live circuit.• Test the circuit locked out – verifying no voltage present• Then retest the meter on a known live circuit to make sure the meter is working

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Job briefings are usually conducted using a tool such as JSA or safe work permit.The lead person on the job would complete the safe work permit and hold ameeting (job briefing) with all parties involved including contractors. The jobbriefing should be documented and maintained on file.

The purpose of the job briefing is to engage all personnel, identify potential hazardsand ensure best practical controls are used to manage the risk. This gives everyonea chance to speak up and communicate hazards.

The purpose of the energized electrical work permit is to make sure all othercontrols have been thoroughly vetted and there is no other option but to work onan energized circuit or expose employees to an arc flash hazard. Working on or nearan energized conductor or circuit part should be your last resort, all other optionsmust be considered.

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Because there is such an urgency to rescue personnel from electric shock or arc flashinjuries the site must have an emergency response procedure developed.Remember as you develop your emergency response procedure, anyone going intothe restricted approach boundary must be a qualified worker and anyone going intothe arc flash or limited approach boundary must be escorted by a qualified worker ifnot qualified themselves.

Methods for releasing a victim from contact with exposed energized conductors orcircuit parts could include; de-energizing the circuit or physically pulling a person offwith a insulated device.

Make sure you have this addressed in your procedure and have appropriate numberof personnel available.

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It is important that the employer has a process to ensure who they deem “QualifiedPersons” who can demonstrate understand of the equipment and hazards associated withthe work they are performing.

There is not a safety class alone that certifies or qualifies a person to work on or nearenergized circuit conductors or parts. The employer is responsible to ensure the person(s)have the safety training as well as the technical training to meet the requirements as statedhere.

Just because you are qualified for one piece of equipment does not mean you are qualifiedon everything. The qualified person must be able to demonstrate skills and knowledge ofevery piece of equipment they are to be qualified on. For example, a person may bequalified on racking in 480 volt breakers but doesn’t have the skills and knowledge of 4160volt breakers. Therefore not qualified on the 4160 volt system.

The employer shall document that each employee has received the trainingrequired. This documentation shall be made when the employee demonstratesproficiency in the work practices involved and shall be maintained for the durationof the employee’s employment. The documentation shall contain the content of thetraining, each employee’s name, and dates of training.

Documentation of on the job training for qualifying electrical workers may include

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signed qualifications cards or checklists, or the equivalent.

Content of the training could include one or more of the following: course syllabus,course curriculum, outline, table of contents or trainingobjectives.

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You are professional operators and technicians. You better than anyone should know thehazards associated with energy. Within a plant you may have energy levels from 480 volts,to 4160 and 13.8kv. If not managed properly, people can get seriously injured or evenkilled, we saw these statistics in an earlier slide.

We have to conduct the risk assessment to determine hazards and how to manage theserisks. This includes identifying the incident energy, practical controls measures, job briefingsand oversight.

The next few slides we are going to look closer at activities you may be responsible at yourfacility and how to manage these risks.

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It doesn’t matter whether the voltage is 480 or 4160 vac. The nature of the activity isconsidered exposing employees to flame or electric arc hazard. In the case ofracking breakers in and out, it doesn’t matter if the door is opened or closed.

You are required to conduct a job briefing; if the task is routine the briefing can beshort but must still cover the requirements listed earlier.

You must be able to estimate the incident energy, either through an incidentanalysis or using available data from NFPA 70E or OSHA 1910.269. Consider using aremote racking system which removes the employee from the exposed hazard andoutside arc flash protection boundary. Remember, distance from the exposed circuitis protection and may not require arc flash protection to be worn.

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These are just a few of the common activities that may be performed at your site.There a re other tasks that can be found in NFPA 70E.

The levels of arc flash protection will vary and is determined on the incident energylevels. If it is required based on the activity, you;ll need to estimate the incidentenergy to determine appropriate level of PPE.

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How many times have you racked in a 480 volt breaker on a motor control center.?In this case the employee completed maintenance on a motor and released thelockout tagout. As he racked in the breaker a fault occurred; a majority of the flashwas contained within the cubicle with a minor arc blast and associated debrisescaping the front of the panel.

The employee was wearing proper PPE and was not injured. Shaken up, yes. As heexplained it, it happened all of a sudden. “I just froze, after the fact I thanked mysupervisor for supplying the face shield and fire retardant clothing.”

You do not know when a fault is going to occur, so follow the JSA and the jobbriefing steps, and always always wear the required PPE.

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O&M Technicians were working in PDC 1. Their planned tasks included:

Removing 6 locks from CGT2 Starting Motor Cell (breaker racked out)

Remove breaker from CGT2 cell

Install grounding truck rails in CGT2

Install grounding truck on rails

Rack grounding truck in manually part way

Close doors to breaker

Set up remote racking controls

Rack in grounding truck with remote device

When using the remote tool to rack in the grounding truck, an arc flashoccurred. The electrical event resulted in direct equipment damage to abreaker and the grounding truck and the possibility of a serious injury.

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Here is a picture of an electric fault in a 4160 volt breaker for a cooling tower pump.It is important to know faults can happen at any time without any warning; thispump was running when the fault occurred. You can see that the arc flash shot outthe front of the panel. It is imperative that all screws and panel locks are properlysecured. The front panel would have prevented the arc fault from escaping if it wasproperly secured.

This is an example why NFPA specifically lists proper installation, propermaintenance, panels/doors secured and no visible damage as a condition requiredwhen determining exposure.

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Remember OSHA states anything over 50 volts need to be guarded and falls under theregulations for arc flash protection.

These are just a few examples of faults and incidents that are captured on the earlier slidewhich discusses injury statistics.

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Contractors working on or near energized conductors or circuit parts need to bemade aware of systems hazards.

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