1、 An Americ An n At ion Al St An d Ar d NECA 700-2010 Standard for Installing Overcurrent Protection to Achieve Selective Coordination Published by National Electrical Contractors Association#! o! “# %!$!# !o#o #o % #% oo!#o n meri%n %tion%l St%nd%rd $“ en;0onally lef; blank ore;ord v Sope %rduct a=d
2、 ?licati=s =cluded %rduct a=d ?licati=s xcluded Regulatry a=d $ther Require=s %wer Systers urs “vi=g Walks Wheelchair !ifts a=d Stairway hairlifts # rticle ru=dault %rtecti= f qui?rt ircuit a=d rdi=ati= Studies u=dault %rtecti= f qui?ds f chievi=g Selective rdi=ati= nne e*erene St%nd%rds !%en;0onall
3、y lef; blank% a;0onal le*;90*al ns;alla;0on “;an+a9+s are desig=ed t ive c= af electrical c=struc ti= services They defi=e a f quality a=d wrkr i=stalli=g electrical ?rducts a=d syste be ref ere=ced i= c=tract dcur electrical c= structi= ?rjects The fllwi=g la=guage is rectective devices shuld be i=
4、stalled i= accrda=ce with # “;an+a9+ fo9 ns;all0ng =e9*u99en; P9o;e*;0on ;o *h0e=e “ele*;0=e oo9+0na;0on #S *se f “ is vlu=tary a=d the #ati=al lectrical =tractrs ssciati= assu bligati= r lia bility t users f this ?ublicati= xiste=ce f a sta=dard shall =t ?reclude a=y r = f # frr usi=g alter=ate c=s
5、tructi= ds ?er=s This ?ublicati= is =t i=te=ded as a substitute fr qualified desig= ?rfessi=als Selective crdi=ati= f vercurre=t ?rtective devices requires the a=alysis a=d c= f vercurre=t ?rtective device tirt circuit curre=t withi= a= electrical distributi= sys teuld be ?erfr= f qualified i=dividu
6、als such as by qualified ?rfes si=al e=gi=eers This ?ublicati= is i=te=ded t c=al lectrical de # ecause they are quality sta=dards “ bey=d the f the # t is the res?=sibility f users f this ?ublica ti= t ccal electrical cdes whe= i=stalli=g electrical ?rducts a=d syste=s fr revisi=s a=d ive this sta=
7、dard are welculd be addressed t # Sta=dards Safetyethesda “etr e=ter Suite ethesda “ ax ne0sne*ane;o9g wwwne*ane0so9g T ?urchase a;0onal le*;90*al ns;alla;0on “;an+a9+s c=tact the # $rder esk at tel fax r rderdesk=eca=etrg “ ca= als be ?urchased i= ?df dw=lad fr?yright #ati=al lectrical =tractrs ssc
8、iati= ll rights reserved *=authrized re?rducti= ?rhibited a;0onal le*;90*al ns;alla;0on “;an+a9+s “ a=d the “ lg are registered tradef the #ati=al lectrical =tractrs ssciati= #ati=al lectrical de a=d # are registered tradef the #ati=al ire %rtecti= ssciati= Qui=cy “assachusetts llus;9a;0ons an+ ;abl
9、es 79o=0+e+ byThis ciated c?yrights are ?r?rietary t a=d used with ?er= f Sch=eider lectricThis ciated c?yrights are ?r?rietary t a=d used with ?er= f ?er ussa= ore;ord #h0s fo9ewo9+ 0s no; a 7a9; of ;he s;an+a9+#h0s 7age 0n;en;0onally lef; blank This sta=dard describes the a?licati= ?rcedures fr se
10、lecti=g a=d adjusti=g lwvltage vercurre=t ?rtective devices t achieve selective crdi=ati= rod9ts %nd ppli%tions nl9ded This sta=dard cvers the i=stallati= f lwvltage vercurre=t ?rtective devices circuit breakers a=d fuses rated vlts a=d less fr selective crdi=a ti= i= electrical distributi= syster r
11、eside=tial c=s t a?lies t a evices rated + a=d less b uses c ircuit breakers rod9ts %nd ppli%tions es =t a?ly t a $vercurre=t ?rtective devices rated tective relays c %rtecti= f c=ductrs tra=sfrtrs r ther equi?r= i= this ?ublicati= is i=te=ded t c=fr the #ati=al lectrical de #S #% Sta=dard =stallers
12、 shuld always fllw the # a?licable state a=d lcal cdes a=d =s whe= i=stalli=g vercurre=t ?rtective devices b $=ly qualified ?ers=s fa=struc ti= a=d ?erati= f vercurre=t ?rtective devices shuld ?erfrrk described i= this ?ublica ti= ll wrk shuld be ?erfrrda=ce with #% “;an+a9+ fo9 le*;90*al “afe;y 0n
13、;he er S=stems ?arts f facilities that require S c=ti=uus ?erati= fr the reas=s f ?ublic safety e=al security r busi=ess c=ti=uity o;nstre%m The directi= that is away frurce f ?wer i= a= elec trical distributi= syste= as the =rw tward the lad mer+en= systef circuits a=d equi? S=stem su?ly alter e%lt
14、h%re =ate ?wer t a lif ?rescribed fu=cti=s vital t the ?rtecti= f life a=d safety mer+en= Thse syster ther cdes r by a=y gver= = These syste aut= ?wer r bth t desig =ated areas a=d equi?f failure f the =r r i= the eve=t f accide=t t elef a syste su?ly distribute a=d c=trl ?wer a=d illu= esse=tial fr
15、 safety t hua= life e*initionsssenti%l systef alter=ate letri%l surces f ?wer a=d all c= S=stem =ected distributi= syste e=sure c=ti=uity f electrical ?wer t desig=ated areas a=d fu=cti=s f a health care facili ty duri=g disru?ti= f =rwer surces a=d als t = withi= the i=ter=al wiri=g syste=sisti=g f
16、 circuits S=stem a=d equi?r e%lth%re delayed autr =ecti= t the alter=ate ?wer surce a=d that serves ?ri=al c=ecti= f a ?wer syste=ductr fte= resulti=g i= a= ab=rw f curre=t aults ty?ically ?rduce higher vercurre=t tha= d verlads de?e=di=g u?= the fault iws utside its =r=al electrically c=ducti=g c=e
17、cti= betwee= a= u=gru=ded c=ductr f a= electrical circuit a=d the =r =curre=tcarryi=g c=ductrs sures r earth ro9nd%9lt syste ?rvide rotetion o* ?rtecti= f equi?gru=d fault curre=ts by ?erati=g t cause a disc=ecti=g ?e= all u=gru=ded c=ductrs f the faulted circuit This ?rtecti= is ?rvided at curre=t
18、levels less tha= thse required t ?rtect c=ductrs frugh the ?erati= f a su? ?ly circuit vercurre=t device e+%ll= eq9ired Thse syste St%nd0on “ele*;0=e oordin%tion Short ir9it = vercurre=t resulti=g frf =egligible i=ductrs havi=g a differe=t ?te=tial u=der =r?erati=g c=di ti=s The fault ?ath =ductrs v
19、ia earth t =eutral shrt circuit is fte= i= excess f te= tif the electrical distrib St9d= uti= syste=ductrs i=cludi=g utility surces rati=gs a=d ir =site ge=erati= r fault curre=t c=tributi= tra=sfr=ductr sizes = ty?es wiri=g ds a=d le=gths t calculate the available shrtcircuit r fault curre=t at key
20、 c=ecti= ?i=ts withi= the systert circuit study is =ecessary t deter?ri ate i=terru?ti=g rati=gs a=d equi?rtcircuit curre=t rati=gs a=d t allw fr bth a crdi=ati= study a=d i=cide=t e=ergy arcflash study “pstre%m The directi= that is tward the surce f ?wer i= a= electrical distributi= syste?site f th
21、e =r= f curre=t flw tward the lad $one Seletive c= a=d c=trl nterlo/in+ syste=ic tri? circuit breakers t cther t ide=tify the clsest u?streartcircuit r gru=dfault which ?erates with = i=te=ti=al ti further u?strea?erate u=der their =rtecti= t the dw=strea=e selective i=ter lcki=g is a?licable t shrt
22、cir cuit a=d gru=dfault ?rtecti= #! o! “# %!$!# !o#o #o % #% oo!#o The gal f selective crdi=ati= is t liutage =ly t that ?rti= f the electrical sys tevercurre=t verlad gru=d fault r shrt circuit What that vercurre=t ?rtective device circuit breaker r fuse clsest t the vercurre=t is the =ly vercurre=
23、t ?rtective device that ?erates t clear the vercurre=t Whe= a= electrical systet selectively crdi =ated tw r vercurre=t ?rtective devices i=cludi=g devices that are u?streaf the device clsest t the faulted r verladed ?rti= f the syste?erate t clear the vercurre=t This de e=ergizes a larger ?rti= f t
24、he electrical syste islate the vercurre=t !ads that wuld therwise be u=affected by the vercur re=t c=diti= ex?erie=ce a= utage whe= a= electri cal systet selectively crdi=ated The #ati=al lectrical de requires selective cr di=ati= f vercurre=t ?rtective devices fr certai= life safetyrelated equi?=s
25、%wer Syster $%S rticle sse=tial systef ealthcare facilities rticle because they are treated as rs durs =al require gru=dfault ?rtecti= f equi?rdi=ati= f vercurre=t ?rtective devices is accice f vercurre=t ?rtective devices a=d their rati=gs r setti=gs The ?ages that fllw ?rvide recr i=stalli=g vercu
26、rre=t ?rtective devices t achieve selective crdi=ati= based u?= the available fault curre=t withi= the systef vercurre=t ?rtective devices a=d electrical distribu ti= syste desig= ?araeters ntrod9tion The #ati=al lectric de ide=tifies several i=stalla ti=s where vercurre=t ?rtective devices their ra
27、t i=gs a=d setti=gs rdi=ated mer+en= S=stems rtile # rticle i=cludes a requirevercurre=t ?rtective devices be selec tively crdi=ated with all su?ly side vercurre=t ?rtective devices Tw exce?ti=s t this require r=dary vercur re=t ?rtective devices where there is =ly =e set f ?rtective devices = the t
28、ra=sfr=dary a=d Tw vercurre=t ?rtective devices f the savercurre=t ?rtective device su?lyi=g a ?a=elbard that has a vercurre=t ?rtec tive device e+%ll=eq9ired St%nder S=stems rtile # rticle a?lies the sau=d i= # rticle t critical ?erati=s ?wer systef healthcare facilities f rticle f a healthcare fac
29、ility is a systef su?lyi=g a liu=t f lighti=g a=d ?wer service t desig=ated areas a=d fu=cti=s f a health care facility that are c=sidered esse=tial fr life safety effective hs?ital ?erati= a=d rderly cessati= f ?rcedures duri=g the tirr a=y rea s= The esse=tial electrical syste the equi?f a healthc
30、are facility is a systef circuits a=d equi?r delayed autr =ecti= t the alter=ate ?wer surce a=d that ?rir electrical equi?r ?atie=t care a=d fr basic hs?ital ?erati= %# m#r$#*!y y/t#m f circuits a=d equi? su?ly alter =ate ?wer t a lif ?rescribed fu=c ti=s vital t the ?rtecti= f life a=d safety The e
31、f a healthcare facility is li circuits esse=tial t life safety a=d critical ?atie=t care which are se?arated a=d desig=ated the life safety bra=ch a=d the critical bra=ch The life safety bra=ch su?lies ?wer fr lighti=g rece?tacles a=d equi?r ty?ical buildi=g life safety equi?tw r wer fr task illu= f
32、ixed equi?wer circuits servi=g critical health eq9irements care areas a=d ther critical fu=cti=s related t ?atie=t care y its refere=ce t # rticle # rticle i=cludes a requirevercurre=t ?rtective devices be selectively crdi=ated with all su?ly side vercurre=t ?rtec tive devices with tw exce?ti=s See
33、Secti= lev%tors 9m&;%iters s%l%tors ovin+ #%l/s #heelh%ir i*ts %nd St%ir;%= h%ir i*ts rtile # rticle i=cludes a requirevercurre=t ?rtecti= assciated with each disc= =ecti=g r elevatrs durs rdi=ated with a=y ther su?lyside vercurre=t ?rtective devices where =e drivi=g =ecti=g re tha= =e drive = feede
34、r a=d is i=te=ded t ?reve=t a= vercurre=t = the ladside f =e drive =ecti=g wer t additi=al drive = feeder by causi=g the ?era ti= f the feeder vercurre=t ?rtective devicero9nd%9lt rotetion o* q9ipment The # requires gru=dfault ?rtecti= f equi? =ecti=g r a service is rated ar = a slidlygru=d ed wyec=
35、ected systef lts t gru=d but =t exceedi=g vlts ?haset?hase # rticles a=d #lt%!r# !&l&t&#/ Whe= gru=dfault ?rtecti= f equi? vided fr healthcare facilities i= accrda=ce with # rticle r rticle i=cludes a requirer =e additi=al level f gru=d fault ?rtecti= fr equi?= all =ext level disc= =ecti=g w=streawa
36、rd the lad This requirer exa ?reve=t a gru=dfault = a bra=ch circuit frwer t u=affected lads by causi=g the ?erati= f the gru=dfault ?rtecti= ?rvided = the r service disc=ecti=g u=d fault ?rtecti= fr healthcare facilities be selectively crdi=ated such that =ly the dw= strear lad side device ?e=s fr
37、gru=d faults = the lad side f that device # rticle hwever des =t ?er=al level f gru=dfault ?rtecti= t be i=stalled = the lad side f a= esse=tial electrical syste=site ge=eratrs a=d esse=tial electrical syster = electrical systet slidlygru=ded wye c=ected systelts t gru=d but =t exceedi=g vlts ?haset
38、?hase See Secti= m#r$#*!y y/t#m/ = accrda=ce with # rticle the alter=ate ?wer surce fr a= et required t have gru=dfault ?rtecti= f equi? =ecti=g have gru=dfault i=dicati= #$lly #qu&r#“ t*“by y/t#m/ = accrda=ce with # rticle the alter=ate ?wer surce fr a legally required sta=dby systet required t hav
39、e gru=dfault ?rtecti= f equi?u=dfault ?rtecti= f equi? vided fr the r service disc=ecti=g r critical ?erati=s ?wer systerda=ce with # rticles r # rticle i=cludes a requirer =e additi=al level f gru=d fault ?rtecti= fr equi?= all =ext level feeder disc=ecti=g w=streaward the lad #! o! “# %!$!# !o#o #o % #% oo!#o
