Seguridad Electrica 1

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Then we’ll examine theindependent safety and stan-dards organizations, includingthe National Fire ProtectionAssociation (NFPA), the Ameri-can National Standards Institute(ANSI), the Institute of Electri-

cal and Electronics Engineers(IEEE) and the InternationalElectro-Technical Commission(IEC). Though they’re not part of government, they too help setthe rules of the safety game.

The government agencies

First, where did OSHA and NIOSHcome from, and what do theydo?

Both agencies were createdby the federal Occupational

Safety and Health Act of 1970.OSHA is in the U.S. Departmentof Labor and is responsiblefor developing and enforcingworkplace safety and healthregulations. In addition, manystates have their own occupa-tional safety agencies that workwith OSHA and govern work-place safety on the state level.

NIOSH is an agency of theU.S. Department of Health andHuman Services, established tohelp assure safe and healthfulworking conditions by providingresearch, information, education,and training in the field of occu-pational safety and health.* Source: Liberty Mutual Workplace Safety

Index, Winter 2008

Alphabet soup

There’s no question that elec-trical safety is a key concernfor electricians and engineers,their employers, unions and thegovernment.

Every day, an average of 4,700 workers in the U.S. sufferdisabling injuries on the job.Insurance industry estimatesput the direct cost of workplaceinjuries in 2005 at more than$8 billion.* With costs that high,no wonder so many governmentagencies and private groups holdpieces of the safety puzzle.

Who sets the rulesfor electrical testing

and safety?

F r o m t h e F l u k e D i g i t a l L i b r a r y @ w w w . f l u k e . c o m / l i b r a r y

Application Note

To maximize safety for your-self and your team, you need asolid understanding of the rulesand standards that govern safeelectrical work. This article willhelp you cut through the alpha-bet soup of safety organizationnames to see how each plays arole in safety.

We’ll check them out in twogroups. First, we’ll look at thegovernment agencies that over-see workplace safety, such asthe U.S. Occupational Safety andHealth Administration (OSHA)and the National Institute forOccupational Safety and Health(NIOSH).



2 Fluke Corporation Who sets the rules for electrical testing and safety?

In other words, OSHA sets andenforces the rules, while NIOSHprovides helpful information onworkplace safety. Here are someexamples:

Several OSHA regulations havean impact on electrical work-place safety. For instance:• 29 CFR (Code of Federal

Regulations) 1910 SubpartI sets standards for PersonalProtective Equipment (PPE),including eye and face protec-tion, footwear and protectionfor electrical workers, suchas insulating blankets, glovesand sleeves.

• The key electrical safety rulesare part of 29 CFR 1910Subpart S, including designsafety standards for electricalsystems, safe work practices,

maintenance requirementsand safety requirementsfor special equipment. Thisregulation also covers trainingrequirements, sets guide-lines for work on energizedparts, outlines lockout/tagoutprocedures and provides rulesfor use of PPE in electricalwork. The OSHA web siteprovides other electrical safetyresources at http://www.osha.gov/SLTC/.

While OSHA sets the broad safetyagenda, it leaves some details toothers. For example, the OSHAelectrical safety rules in 1910Subpart S specifically refer thereader to NFPA and ANSI codesand standards for help in com-plying with OSHA. These includeNFPA 70E (Standard for ElectricalSafety in the Workplace), ANSI/NFPA 70 (National ElectricalCode) and others. Subpart S wasupdated in August 2007 and fur-ther amended in October 2008.

Here’s an example of how thestandards work together. OSHA’ssafety-related work practicestandards in Subpart S do notcurrently address flame-resistant(FR) clothing. However, OSHAstandard 29 CFR 1910.335 (a)(2)(ii) requires use of protective

shields, protective barriers, orinsulating materials to protectemployees from shock, burns orother electrically related injurieswhile working near exposedenergized parts or where dan-gerous electric heating or arcingmight occur. Chapter 1 of NFPA70E-2009 contains specificrequirements and methodologyfor hazard assessment and selec-tion of protective clothing andother personal protective equip-ment. Employers may follow

NFPA 70E flash-hazard require-ments as a way of meeting theOSHA standard.

The key distinction is this:OSHA 1910 Subpart S and other

OSHA safety and health stan-dards are law. Failure to followthese standards could result in acitation, a work shutdown, finesor other sanctions. The NFPA,ANSI and other standards OSHArefers to, on the other hand, areintended as guidelines to safety.

“We’re pointing employersand employees to these docu-ments as sources for additionalinformation,” said David Wallis,director of the OSHA office of engineering safety. “For safe

work practices there are somegeneral-type requirements inOSHA 1910 related to protectionfrom electric shock and elec-tric arc hazard. Employers canlook toward NFPA 70E for morespecific information about thekind of equipment they need toprotect their employees.”

“There is another caveat Imight explain,” Wallis continued.“Sometimes OSHA will have aspecific requirement not con-tained in NFPA 70E, or where

the 70E provision might not bequite as stringent. In that case,OSHA would expect employ-ers to comply with the OSHAstandard. Compliance with NFPA70E would not automatically beconsidered adequate.”

Key Points:

• Both employers and employees are responsibleto know and follow OSHA standards.

•Citations and penalties may be imposed if standards are not observed.

• Other safety standards, including NFPA 70E,provide guidance on safety measures andprocedures. They do not supplant OSHA.In case of conflict, follow OSHA standards.




NFPA establishes stan-dards through consensus

Outside government, a key playerin establishing electrical safety

practices is the nonprofit NationalFire Protection Association. TheNFPA sets and updates more than300 safety codes and standards,covering everything from build-ing construction to connectors forfire hose. NFPA standards are setthrough consensus, developedby more than 200 committees of volunteers from industry, unionsand other interest groups.

For electrical workplacesafety, the key NFPA standard isNFPA 70E, Standard for Electri- cal Safety in the Workplace .The 2009 edition was issuedby the NFPA Standards Counciland approved as an AmericanNational Standard in September2008. NFPA 70E is written tocorrelate with the National Elec-trical Code (NEC), which many jurisdictions adopt as part of localbuilding codes and regulations.But NFPA 70E focuses on suchissues as safety-related workpractices, maintenance of safetyequipment, safety requirementsfor special equipment and safety-related installation requirements.

NIOSH: Helpfulinformation

While OSHA sets the rules, andsometimes levels penalties,

NIOSH provides useful safetyinformation. A good exampleis a new 88-page electricalsafety handbook, Electrical Safety —Safety and Healthfor Electrical Trades Student Manual, available for download-ing in portable document format(PDF) at http://www.cdc.gov/niosh/docs/2002-123/2002-123a.html. The NIOSH web sitealso provides a number of elec-trical safety alerts, reports andlinks to other electrical safetyresources.

Key Point:

• NIOSH is a valuable sourceof electrical safety informa-tion, but is not a regulatoryagency.

It is intended for use by employ-ers, employees, and OSHA.

NFPA 70E uses six categoriesof hazard and risk for electri-cal work, from minus one up to

four. As the work environmentand the type of job become morehazardous, the need for protec-tion increases. The standardmakes it clear that test equip-ment is an integral part of thePPE electrical workers must useon the job and must be inspectedbefore each shift. In addition,test equipment must be ratedand designed for the circuits andenvironments where it will beused. To clarify what this means,the 2009 Edition of NFPA 70E

now refers users to ANSI/ISA-61010-1 (82.02.01)/UL 61010-1,the standard first established asIEC 61010.

The NFPA 70E standardprovides extensive informationon what it takes to work safely,and to run an effective electricalsafety program. It provides guid-ance on employee training, workplanning and procedures (includ-ing lockout/tagout) and use of PPE. Whether you’re a profes-sional electrician, an apprentice

or a supervisor, NFPA 70E is mustreading. And don’t forget, OSHAalso refers to NFPA 70E.

Key Points:

• NFPA 70E is a key resource for bothemployers and employees. It containsdetailed instructions on PPE and safework procedures required for specific tasks.

• This standard specifically defines testequipment as part of PPE.

ANSI sets standards forequipment

The American National StandardsInstitute (ANSI) also plays a rolein electrical safety. This private,nonprofit organization admin-isters and coordinates the U.S.voluntary standardization andconformity assessment system.And it represents the U.S. ininternational standards organiza-tions, such as the InternationalOrganization for Standardization

(ISO) and the IEC.




ANSI/ISA S82.02

ServiceEntrance

Meter

Meter

ServiceEntrance

Meter

Outbuilding

OutbuildingTransformer

Underground Service

Underground Service

ServiceEntrance

Cat I

• Electronicequipment

• Low energyequipmentwith transientlimitingprotection

• Any high-voltage,low-energysource derivedfrom ahigh-windingresistancetransformer

Cat II

• Appliances andportable tools

• Outlets and longbranch circuits– Outlets at

more than10 m (30 ft.)from CAT IIIsource

– Outlets atmore than20 m (60 ft.)from CAT IVsource

Cat IV

• Origin of installation: wherelow-voltage connection is madeto utility power

• Electricity meters, primaryovercurrent protection equipment

• Outside and service entrance

• Service drop from pole to building

• Run between meter and panel

• Overhead line to detachedbuilding

• Underground line to well pump

Cat III

• Equipment in fixed installations:switchgear and three-phase motors

• Bus and feeder in industrial plants

• Feeders and short branch circuits

• Distribution panel devices

• Heavy appliance outlets with short

connections to service entrance

• Large lighting systems

standards for voltage test equip-ment used in environments of up to 1000 volts. The pertinentstandards include ANSI S82.02,CSA 22.2-1010.1 and IEC 61010.These standards cover systemsof 1000 volts or less, including480-volt and 600-volt, three-phase circuits. For the first time,these standards differentiate thetransient hazard by location andpotential for harm, as well as thevoltage level.

In addition, the 2000 edition

of IEC 61010 requires that mul-timeters and similar equipmentshall not cause a shock, fire,arcing or explosion hazard evenif subjected to operator error (forinstance, connecting the meter toan energized circuit when set tothe ohms position). Fluke metersnot only protect the user in suchcircumstances—they also protectthemselves, and keep working.ANSI and CSA are now in theprocess of adopting these morestringent IEC standards.

OSHA electrical safety regula-tion 1910 Subpart S refers toseveral ANSI standards. The keyANSI standards involving electri-cal safety are ANSI C33.27-74

(Safety Standard for Outlet Boxesand Fittings for Use in Hazard-ous Locations) and ANSI S82.02(see below), which providesimportant safety rules for electri-cal test instruments. ANSI C2-81(National Electrical Safety Code)deals with electric installationsof more than 1000 volts, an areabeyond the scope of this article.

Key Point:

• Employers and technicians

should be familiar with ANSIelectrical safety standardsC33.27-74 and S82.02 and,if applicable, C2-81.

IEEE helps calculate arcflash hazard

Another authority in safety isthe Institute of Electrical andElectronics Engineers. IEEE1584-2002, Guide for Performing Arc-Flash Hazard Calculations ,

(amended as IEEE 1584a in Sep-tember 2004) does just what itstitle suggests, providing techni-cal information employers canuse to determine the arc flashhazards present in the work-place. IEEE publishes a numberof other useful safety standardsand practice guides, including thetwelve-volume IEEE Color Books

series.

Key safety rules frominternational partners

To make electrical measure-ments safely, it pays to stretchyour horizons. Some of the mostimportant safety guidelines forelectrical measurement havebeen developed in cooperationwith the IEC, the leading globalorganization that prepares andpublishes international standardsfor all electrical and relatedtechnologies.

ANSI, the Canadian StandardsAssociation (CSA), and the IEChave created more stringent

These standards establish animportant four-category systemfor rating the electrical hazardselectricians face when takingmeasurements on so-called “lowvoltage” equipment—up to 1000volts.

ANSI, CSA and IEC definefour measurement categories of over-voltage transient impulses(voltage spikes). The rule of thumb is that the closer the tech-nician is working to the powersource, the greater the danger

and the higher the measurementcategory number. Lower categoryinstallations usually have greaterimpedance, which dampenstransients and helps limit thefault current that can feed an arc.• CAT (Category) IV is asso-

ciated with the origin of installation. This refers topower lines at the utility con-nection, as well as the serviceentrance. It also includesoutside overhead and under-ground cable runs, since both

may be affected by lightning.




Transient protection

The real issue for meter circuitprotection is not just the maxi-mum steady state voltage range,but a combination of both steady state and transient overvoltage withstand capability . Tran-sient protection is vital. Whentransients ride on high energycircuits, they tend to be moredangerous because these circuitscan deliver large currents.

If a transient causes an arc-over, the high current can sustainthe arc, producing a plasmabreakdown or explosion, whichoccurs when the surrounding airbecomes ionized and conduc-tive. The result is an arc blast, adisastrous event which causesnumerous injuries every year.

• CAT III covers distributionlevel wiring. This includes480-volt and 600-volt circuitssuch as three-phase bus andfeeder circuits, motor control

centers, load centers anddistribution panels. Perma-nently installed loads are alsoclassified as CAT III. CAT IIIincludes large loads that cangenerate their own transients.At this level, the trend tousing higher voltage levels inmodern buildings has changedthe picture and increased thepotential hazards.

• CAT II covers the receptaclecircuit level and plug-in loads.

• CAT I refers to protected elec-

tronic circuits.Some installed equipment mayinclude multiple categories. Amotor drive panel, for example,may be CAT III on the 480-voltpower side, and CAT I on thecontrol side.

A higher CAT number refersto an electrical environmentwith higher power available andhigher-energy transients. Thisis a key principle to understandwhen it comes to choosing andusing test instruments. A mul-timeter designed to a CAT IIIstandard can resist much higher-energy transients than onedesigned to CAT II standards.Within a category, a highervoltage rating denotes a highertransient withstand rating, e.g.,a CAT III-1000 V meter hassuperior protection compared toa CAT III-600 V rated meter.

Key Point:

• The hazard category systemdetailed by ANSI, CSA andIEC provides useful informa-tion for preparing against thehazards of transient voltageimpulses (voltage spikes) inthe environments where mostindustrial electricians work.

The concept of categoriesis not new and exotic. It issimply an extension of the samecommon-sense concepts thatpeople who work with electric-

ity professionally use every day.It’s another tool you can use tobetter understand the hazardsyou face on the job, and worksafely.

All of the regulations we havecovered are built in the sameway. They grow from experience,and they are based on experi-ence and sound, common senseprinciples. No tool, however, cando the job alone. It’s up to you,the user, to learn these safetyregulations and standards, and

use them effectively on the job.After all, it’s your safety atstake. Read up, and work safely.

Independent testing labs help ensure safety compliance

You want your tools and equipment to help you work safely. But how do youknow that a tool designed to meet a safety standard will actually deliver theperformance you are paying for?

Unfortunately it’s not enough to just look on the box. The IEC develops andproposes standards, but it is not responsible for enforcing the standards. Word-ing like “Designed to meet specification ...” may not mean a test tool actuallyperforms up to spec. Designers’ plans are never a substitute for an actual inde-

pendent test.That’s why independent testing is so important. To be confident, check theproduct for the symbol and listing number of Underwriters Laboratories (UL),the CSA, TÜV or another recognized testing organization. Those symbols canonly be used if the product successfully completed testing to the agency’s stan-dard, which is based on national/international standards. That is the closestyou can come to ensuring that the test tool you choose was actually tested forsafety.

What does the CE symbol indicate?

A product is marked CE (Conformité Européenne) to show it conforms to health,safety, environment and consumer protection requirements established by theEuropean Commission. Products from outside the European Union cannot besold there unless they comply with applicable directives. But manufacturers

are permitted to self-certify that they have met the standards, issue their ownDeclaration of Conformity, and mark the product “CE.” The CE mark is not,therefore, a guarantee of independent testing.

UnderwritersLaboratories (UL)

Canadian StandardsAssociation (CSA)

TUV and VDE (German stan-dards organizations) areapproval/listing agencies




Fluke Corporation

PO Box 9090, Everett, WA 98206 U.S.A.Fluke Europe B.V. PO Box 1186, 5602 BDEindhoven, The Netherlands

For more information call: In the U.S.A. (800) 443-5853 orFax (425) 446-5116In Europe/M-East/Africa +31 (0) 40 2675 200 orFax +31 (0) 40 2675 222In Canada (800)-36-FLUKE orFax (905) 890-6866From other countries +1 (425) 446-5500 orFax +1 (425) 446-5116Web access: http://www.fluke.com

©2004-2009 Fluke Corporation.Specifications subject to change without notice.Printed in U.S.A. 6/2009 2173075 A-EN-N Rev B

Modification of this document is not permittedwithout written permission from Fluke Corporation.

Fluke. Keeping your world up and running.®

Electrical safety rules and standards: Who does what

MandatoryAuthority Standard Title Subject or Advisory? Topics Covered Also refers to

OSHA 29 CFR Electrical Electrical Safety Mandatory Design safety standards for electrical systems, NFPA 70E1910 Subpart S safety-related work practices, safety-related NFPA 70

maintenance requirements and safety ANSI C2-81requirements for special equipment ANSI C33.27-74

OSHA 29 CFR Personal Protective PPE Mandatory Personal Protective Equipment (PPE) including1910 Subpart I Equipment face and eye protection, footwear and

insulating gear

NIOSH None Electrical Safety — Safety Electrical Safety Advisory Electrical Safety guidance for students andand Health for Electrical apprenticesTrades Student Manual

NFPA 70E** Standard for Electrical Electrical Safety Advisory Safety training, work planning andSafety in the Workplace procedures, PPE required for specific work

situations, lockout/tagout and more. Specifiestest tools as part of PPE; details test toolinspection schedules

NFPA 70** National Electrical Code Electrical Safety Mandatory* Electrical installations in buildings, generallyoperating at 600 V or less

ANSI/IEEE C2-81** National Electrical Electrical Safety Mandatory* Governs electric utility and heavy industrialSafety Code installations, often operating in thousands

of voltsANSI S82.02 Safety requirements for Test tool safety Advisory Handheld probe assemblies and handheld

CSA 22.2-1010.1 electrical equipment for current clamps for electrical measurement

IEC 61010 measurement, control, and test. Establishes four categories of

and laboratory use overvoltage transient hazard

IEEE 1584-2002 Guide for Performing Arc Flash Advisory Determination of arc flash hazard Arc-Flash Hazard Calculations

IEEE Color Books 12 titles in series Multiple Advisory Safety and other recommended practices forelectrical work and electrical installations

* Adopted both directly and indirectly in many U.S. and international jurisdictions. ANSI/IEEE C2 is typically adopted by state or local public utility commissions.** Referenced in OSHA 1910 Subpart S: “The following references provide information which can be helpful in understanding and complying with the requirementscontained in Subpart S:”

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Seguridad Electrica 1