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<br /> ' ' ARTICLE 250—GROUNDING 70-127 7�128 NATIQNAL EI.ECTRlCAL CQDE
<br /> � jumper shall be sized in accordance with Table 250=95 using the rating of (b) Metal Frame of the Bullding. The metal frame of the building,`where
<br /> the circuit that may ener�ize�tl�e piping, effectively grounded. . ;S �
<br /> The equip}nent ground�ng conductor far the circuit that may energize the ''
<br /> piping shall be pernvtted to.serve,as the bonding means. ��'�� Effectively grounded means intentionally connectcd to earth thraugh a
<br /> ground connecdon or conneckians�of suH'iciently low imped�r►ce and having suffi-
<br /> (FPN)• Bonding al!piping and me{at air 8ucis within the premises will prcrvide cient cunent-canying capacity to.prevenE tke buitdvp of vottages that may resalt in
<br /> additionat safety. , undue hazard to connected equipment or to petsons. �
<br /> hd,Grour�cltng Eteatrade System (�) �ncrete-Encased Electrode. An electrale encased try at least 2
<br /> inches(50.8 mm}of concrete,.located within and near#he bottom of a con-
<br /> 250-81. Grounding Electrode System. If availabla on the remises at �ete foundation or footing that is in direct contact with the earth,consist-
<br /> each building or struchue served,each item a throu� d belo and an �g of at least 20 feet (6.1 m)of ane or tnore bare ar zinc galvanized or
<br /> { ) t } = Y� other electricaily conductive coated stee] reinfarcing bars or xods of not
<br /> made etecttodes in accordance with Sections 250-8 c and d shall be
<br /> ' � ) � }� less than �/2 inch (12.7 mm) diazneter, or consisting of at least 20 feet
<br /> bonded together to form the grounding electrode system. Interior rnetal 6.1 m of bare co
<br /> water piping locaked more than 5 feet(1S2 cm)from the point of entrance) � � PP'�x�nductor not smaller than No.4.
<br /> ta the build'u�g shall nat be used as a conductor to intezconnect the eleo- (d) Ground R)ng. A ground ring encircling the building or structnre, in
<br /> trodes and the grounding electrode conductor.The bonding jumper shall be ���ed contact with the earkh at a depth below earth surface not less than
<br /> installed in accordance with Sections 25Q-92�a) and (b), shali be sized in ��/2 feet(Z62 mm),co,nsisting af at teast 20 feet(6.i m}of,bare copper con_
<br /> accordance with Section 250-44, and shall be cannected in the mannerf �uctor not smalter thanNo.2. �
<br /> specified in Section 250-115.The unspliced grounding electrode conductor
<br /> shall be pernutted to run to any convenient grounding electroda available �5�� N�8de a�d.Other Electrodes. Where nane of the electrodes s�ec-
<br /> in the grounding eiectrode system.It shall be sized for the largest ground- ��d�Section 250-$1 is avai]able,ane or more of the electrodes specafied
<br /> ing electrode conductor requued among all the available eleckrodes. in(b)through(d)below shall be used.Where practicable,made electrodes
<br /> Exception No. 1: It shall be pe»nitted to splice the,grounding electrode shall be embodded below permanent maisture level.Made electcodes shall
<br /> conductor by means of irreversible compressivn-rype connectors tisted for be free fXom nonconductive eoatings,sueh as paint or enamel.Where more
<br /> the purpose or the exothernric welduig p,rocess. than one electrode is used,each electrode of one grounding system(includ-
<br /> E:rceptiarz No. 2: In irutustriul anrl cotnrrrer�iul6u,iCdin wherr coruli- �g that used for lightning rods)shall nok be less than 6 feet{i.83 m)from
<br /> tior+s af maintenance and supervision ensure that on �Ii d ��.o� �3'°�er etectrade of another grottnding system. '
<br /> will service the installation and t/te entine length of the Zn erior meta[water ��N)� �'�or more electrpcies that aze e�`ectivety bonded together are to be
<br /> F�Pe t�j���'��'used for tlte coruluctor is exposed treated as a singte electrocie system in this sensc, ,, ,
<br /> (F,t'N): See Section 547-8£or special grpunding and bonding requirements for ia) Metal Underground Gas Piping System. A metal undergtound gas
<br /> agricultural buildings, pipmg system shall not be used as a
<br /> ; grounding electtode.
<br /> (a} Metal Underground Water Pipe. A metal underground water pipe in ��} �er[.oca1 Me#al tlndergroand Systems or,Sbue#ures. Qther locaI
<br /> direct contact with the earth for 10 feet (3.05 m) or more (including any metaI underground systems or structures, such�as,piping systems and
<br /> metal well casing effectively bonded to the pipe)and electrically coqtinu- undetground tanks.
<br /> aus(ac made electricaliy eontinuous b�bonding around insulating joints or {e} Rod snd Ptpe Eteetrades, Rod and pipe e]ectrodes shatl not be less
<br /> secttans or insuiating pipe),to the pomts of connectian of the grounding than 8 feet(2.44 m)in length and shall consist of the following materials,
<br /> electrode conductor and the bonding conductors.Continuity of the ground- �nd shall be installed in the following manner:
<br />� ing path or the bond'�ng cor�ection to mterior piping shall not rety on water {1} Electrodes of pipe or conduit shait not be smaller than�f4-inch trade
<br /> meters. A metaI undetgraund water �ipe shall be supplemented by an size and,where of imn or steel,shall have the outer surface galvanized or
<br /> addiHonal electrode af a type specified�n Section 250-81 or in Section 250- atherwise meta!-coated far corrosion gratection.
<br /> 83. The supplemental electrade shall b� permitted to be bonded to the {2) Electrades of rods of.iron or steei s$alI be at Ieast�/8 inch(I5.87 nnm)
<br /> grounding elecfsode conductor, the grounded setvice-entrance conductor, � ��;�ter. 5tainless steel rods less than �/B inch (15.87 mm) in diameter,
<br /> the graunded service raceway,or any graunc�ed service enclosure. , egun•alent shali i�e listed and shall not 6e[ess than
<br /> Wh,�re the supplemental electrode is a made eIectrode as in Section 25Q- �n��e�O�r°ds ar their
<br /> 83(c)or(d), that pqrrtion of khe banding jumper that is the sole connection �2�O��Z2.7 mm}in diamefer. ' ' t �
<br /> to the supplernental prounding electrode shall not be requued to be lazger tengtt�is�n contact�with�the soil.tItlshall be driven�t at c!pth af otnless
<br /> than Na.6 copper w�re or Na.4 aluminum w�re. � than 8 feet (2,q4 m) except that, where rock bottom is encountered, khe
<br /> Fxceptio�t: 77:e supplemental electrode shall be permi#ted to be bonded electrode shall be drrven at an oblique angle not ta exceed 45 degrees fram
<br /> to tlte u:terior meta[water piping crt any converuent paint as covered in the verti+eat or shaEi be buried in a treneh that is at least 2�12 feet(762 mm}
<br /> .Sectian 250-81, F�ceptivn No. 2. • deeg.The upper end af tha electrocie shall be 8ush with ar below ground
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