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ARC FLASH HAZARDAWARENESS & MITIGATION
by
Sesha Prasad
NHP engSPACE
Melbourne
12th November 2014
OVERVIEW OF TOPICS
ntrodu!t"on to Ar! #lash Ha$ards
%r"e& 'verv"e( o& Austral"an Ar! #lash Standards
Ar! #lash PPE S)e!s * N#PA +0E
Ar! #lash Ha$ards "n Modern Po(er Systems
Ar! #lash n!"dent * A Case Study
M"t"gat"on o& Ar! #lash Ha$ards
Ar! #lash Analys"s * Case Study ,emo
Con!lus"ons - .uest"ons
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ARC FLASH HAZARD
Ar! tem) !an rea!h u) to about 20000oC
4 t"mes the tem)erature on suns sur&a!e
#"res "n Petro!hem"!al "ndustr"es 2500oC
Ar! )lasma tem)eratures are 6 7000oC
8aseous !o))er "s 44000 t"mes sol"d metal
Severe or even &atal burns
Cloth"ng !an be "gn"ted several meters a(ay Phys"!al "n9ur"es due to ar! blast
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ARC FLASH IN 415V BOARD
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ARC FLASH IN 415V BOARD
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CAUSES OF ARC FLASH
:e are more !on!erned ("th an ar! &lash"n!"dent (hen a )erson "s (or;"ng nearenerg"sed !ondu!tors
A!!"dental !onta!t
,ro))ed
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CASE STUDIES IEEE 1584
EEE 1754 do!uments a total o& 4?
"n!"den!es
24 "n!"den!es are at @1; 450
10 "n!"den!es &rom 1; to >B>;
5 "n!"den!es &rom >B>; to 17; + "n!"den!es 617;
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CASE STUDIES IEEE 1584
Ele!tr"!"an (as "nstall"ng a &use "n a )anel
An ele!tr"!al !onne!tor tou!hed bra!e bar (h"lera!;"ng "n
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CASE STUDIES IEEE 1584
8round ("re tou!hed the energ"sed )hase lug (h"le
mov"ng ground ("re "ns"de a )anel
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N#PA +0E * 2000 * PPE
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DOUGHTY (NFPA) EUATION
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AUST STANDARDS
ESAA * NENS 0?2004 / ENA NENS 0?200>
Nat"onal 8u"del"nes &or Sele!t"on Fse andMa"ntenan!e o& PPE &or Ele!tr"!al Ha$ards
A))l"!able &or Ele!tr"! Ft"l"t"es
E=uat"on "s based on s"ngle )hase &aults
3GPh Heat #luI J 3 I 1GPh Heat #luI
Cotton dr"ll !loth"ng o& vary"ng th"!;ness/layers
Cotton !an !at!h &"re under ar!"ng !ond"t"ons
157gsm !otton !loth"ng &or 10!al/!m2
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AUST STANDARDS
AS 453> 2011 Sa&e :or;"ng on or near D nstallat"ons
n!luded ar! &lash PPE s)e!s "n 2011 ed"t"on #a!e Sh"eld rated at 10 !al/!m2
Ar! #lash su"t rated at 40 !al/!m2
#lame es"stant 8loves and Prote!t"ve Cloth"ng
Cal/!m2 rat"ngs not s)e!"&"ed &or 8loves and Cloth"ng
Prov"des a table o& PPE s)e!s &or solated :or;S("t!h"ng/solat"on * results "n &alse sense o& se!ur"tyand eI)oses ele!tr"!"an to dangerous !ond"t"ons
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NFPA !"E#$""4 # ISSUES
PPE 3 - 4 * are not !om&ortable
Cotton under(ear* C%'*%+, -.%/ -,' & 0/*2-.%/-
#lame etardant # "s not Ar! es"stant A
:hy s)e!"&y number o& layersK
PPE s)e!"&"!at"on "n !al/!m2 * not layers
PPE
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PPE SPECS NFPA !"E # $"1$
1?
PPE SPECS NFPA !"E # $"1$
N#PA +0EG2012 S)e!s are s"m)le - !lear
S)e!"&"es !loth"ng - other PPE "n same
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SIMPLIFIED PPE TABLE
Note that Cat 1-2 and Cat 3-4 have
e&&e!t"vely same s)e!"&"!at"ons * eI!e)t &or
"n!"dent energy s)e!s
N#PA +0E * 2012 )rov"des an alternat"ve PPE
table "n A))end"I H
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EVERY DAY WOR3 WEAR
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12 Cal / !m2 PPE
WHY 4 CATEGORY TABLE
4 !ategory "s no( relevant only &or the :or;
%ased table )rov"ded "n N#PA +0E
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NFPA !"E $"1$ WOR3 TABLE
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ARC FLASH HAZARD IN
MODERN POWER SYSTEMS
Det us !ons"der 417 s("t!h board su))l"ed by a11;/417 270;A trans&ormer
+;A #ault Devel L
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ARC FLASH HAZARD IN
MODERN POWER SYSTEMS
2+
ARC FLASH CASE STUDY
Ar! #lash 450 1+;A +70;AK 0B57s
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ARC FLASH # CASE STUDY (ESV)
417 S("t!hboard "n !lub house o& a ret"rementv"llage
Ele!tr"!"an (as re)la!"ng an C,
Shorts
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ARC FLASH A CASE STUDY
%urns to &a!e abdomen hands and legs
Shorts
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HAZARD MITIGATION
Ensure &ast !learan!e &or ar! &lash !urrents30 to >0 o& bolted &ault !urrents
Condu!t ar! &lash stud"es to establ"sh ar!&lash energy levels at s("t!hboards
More str"ngent !he!;s on '/C )rot sett"ngs
elays ("th t(o grou)s o& )rote!t"onsett"ngs are no( ava"lable * Fse them
Ar! &lash relays &or h"gh &ault level boards
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CONCLUSIONS
%e A(are o& Ar! #lash Ha$ard
417 S("t!hboards ("th h"gh &ault !urrents are
,angerous
