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<br /> AHTICLE 250--GROUNDlN� 74-127 7¢-12$ NATtQNA1..ELECTRICAI COI}E
<br /> jurnper shall be sized in aocurdance with Table 250=95 using the tating of (b) Mete!Frame ot the Bu!ldins. The metat fcams of the buelding,where
<br /> the circuit thai may ener�ize the piping. • effectively gmunded. � �i} �
<br /> ie
<br /> The equip�nent groundmg conductor for the circuit that may energize the '' ,
<br /> piping shaU be perntitted to serve as the bonding means. (��� �ff�'e�Y B�ounded�means intentionally oonnccted to earth through a
<br /> ground connection or connectians af suffieiently taw impedance and having su8i-
<br /> (FPN}' Bonding all piping and metaE air ducts within the premises will provide cient cncrent-carrying capacity to•prevent the buitdap of voltages that may resutt in
<br /> adaitional safety. , undue hazard to connecxed equipmsnt or to peisons.
<br /> H,Graunding Eteotrode System ��} C°���'�� ���$• � eIectrade encased by at least 2
<br /> . inches(SU.$mm)af concrete,.lacated within and near the bottom�of a oon-
<br /> 250-81. Grounding Electrode System. If available on the remises ,�t ��ke foundation or footing that is in direct oantact with the.earth,consist-
<br /> each building or s#ructure served,each item a throu p � of at leasf?A feet(6.1 m)of ane or mare bare or zinc gatvanized or
<br /> made electrodes in accordance with Sections 250-S�ctdande1 d }hall b( o��r electricalty c�nductive aaated steei reinforcing bara or rods of nat
<br /> banded to ether to forrn the � � � �' 1�� �� �/2 inch (12.7 rnm) diameter, or consisting of.at least 20 feet
<br /> g . grounding electrode system. Interiar metml� {6.1 m)of baze copper coadnctot not smaltez tt�an Na.4.
<br /> water piping lacated more than 5 feet{152 c�n}fram the point of entrance
<br /> ta the bu�lding shall not be used as a conductor to interconnect the elec- (� Ground Ring. A ground ring encircling the building or structure, iun
<br /> trades and the grounding eleckrode conductor.The bonding jumper shall be dir�ct,contact with the earth at a depth below earth surface not less than
<br /> instatled in accordance with Sections 250-92(a) and (b), shal!be sized in 2�2�'�t{7b2.mm),consisting of at least 20 feet{b.l m)afbaze copper con-
<br /> accordance with Sectian 250.94, and shal[ be connected in the manner� ductor not smaller than No.Z. �
<br /> specified in Section 250-115.Tfie unspliced grounding electrode conductar '
<br /> sha11 be pemutted to run.to any convenient graunding etectrade avaitable �� Msde end.Othsr Etectrodes. Where none of the e�ectrocies spec-
<br /> in the grounding ele�trode system.It shail be sized for the largest ground- �ed in Section 25q-81 is available,one or mare of the eteckmdes spec�f'ied
<br /> ing electrade rnnductor requued among all.the available electrodes. �(b)ttuoup�(d)below shall be used:Where practicable,rasacie electrodea
<br /> F.,,xception No. 1: It sha!!be pe,rnritted to sptice the gnounding etectrnde �ha1l be em6edded below ger�anent moistutc level.Made electrales sha11
<br /> conductor by means of umeversi151e compr�ssion-type co�urectors listed for be�ee�om nonconductive coatings,such as paint or enamel.Where more
<br /> tl�e purpiase or the exathemric welding proce,�c. than one electrode is used,each electmde of ane gmunding system(includ-
<br /> ing that used for lightning�rods)shall nat be less thaat 6 feet{1.83 m}from
<br /> Fxcepfion No. 2: In indurirrut arui co»une�inl buitdings wher�conrli- any other electrode of another grounding system. '
<br />; tions of maintenance arul supervision enrwne that only qualified persons
<br /> will servic'e the rrtstallativn and the entine length of the inteniormeta!water ��'�� '�'o or more electrodes that ace effectively bonded together are to bc
<br /> PiPe that is bein,g used for the conductar is�posed treatecl as a siagte electrodc�ystem ia this sensc. ,, _
<br /> (FPN); See Section 547-8 foc epecial grounding and bonding requirements,far • ��1 Metel Undel'ground Gaa Plping•'�ystem. A raetal undergraund gas
<br /> agicutn,ral buildings. piping system shall not be used as a graundiug electrode.
<br /> (�j Metai Underground Water Pipe. A metai under,ground water pipe in i�? �er��Metsl Underground Syateme or,Struefure�. Other Ioca1
<br /> direct contact with the earth for 10 feet (3.OS m) ar more mcludin an metal underground systems or structutes, such as;piping systems and
<br /> meta!wel!casing effectively bc�nded to the pipe}and electr�cally continu ���rgraund tanks. ,
<br /> ous(ar made eleetricalty continuous b�•bondmg around insutating joinis ar• �G) Rad end Plpe Etectrodes. Rod and pipe electmdes shatl not be less
<br /> sections or insulating pipe).ta the potnts of connection of the graunding ��g feet(2.44 m)in length and shall oonsist of We following materials,
<br /> electrode conductor and the bonding conductors.Continuity of the graunii- �d sha(1 be instailed in the followutg manner;
<br /> iag path or the bonding connection to interior piping shall not reiy on water (1) Electrodes of pipe or conduit shall not be smaller than�/4-inah trade
<br /> meters. A metal undergtound water �ipe shall be supplemented by an size and,where of iron or steel,s6all have the outer surface galvanized or
<br /> additional electrade af a type specified�a Section 25Q-81 or in Section 250• athenvise metal-coated far corrosian grotection.
<br /> 83. The supplemental electrade shalt b� permitfed to be bonded to the (2) Electtodes of rods of.iron or steel shall be at least�s inch(15.87 mm)
<br /> graunding electrade conductor,the grounded secvice-entraunce conductor, ,�diameter. Staiiiless steel rads�less than�/s ineH (15.87 mm)'in diameter,
<br /> the�� grounded service raceway,ar any graunc�ed setvice enclosure.
<br /> Wt�re tlte supplemental electrode is a made etectrode as in Secfion 250-��n����°��"°r the�r eqwvalent shall be]�Sted and sl�a]t not be less than i
<br /> 83(c)or(d),that portion of the bondin jumper that is the sale connecdon �Z�Ch t12'�mm��'��ter.
<br /> to the supplementa! aundin ele�tr (3)_The electrode shall be installed such�that at least 8 feet 2.44 m)of
<br /> than No.6 cogper w�re or No 4 alununvm wire t be required to be lazger teng#h�s in cantaet with the soil. It sHall be c�tiven to a depth of not�ess �
<br /> than 8 feet (2.44 m) except that, where rock tiottom is encountered, the
<br /> F.xceQ[ivn: The supplemental electrode shall be permitted to be bonded electrode shall be driven at an obltque angle nat to eaceed 4S degrees from
<br /> to tise rreterior metat water piping at Qny converrient point as covered in the verticat ar shall be buried in a trench that is at least 2�z feet 762 mm �
<br /> Section 250-81, F.xception 1Vo ,� . I deep.The upper end of khe electrode shal!be Hush with or below ound i
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