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ARTiGIE 254—QROUNRINQ 70-127 70-128 NATIONAL ELECTRICAL CODE
jumper shall be sized in accardance with Table 250=95 using the rating of (b) Metel Frame oi ihe BuUding. The metal frame of the building,where
the crccuit that may ener�ize the piping. ef#'ectivcly gcoundecl. ,
The equipment ground�ng conductor for the cucuit khat may energize the ��pN)• Effectively gmunded,means intentionafly connected to esrth through a
piping shall be pernutted to.serve,as the bainding means. � - g�,nnd cannection or oonneclions of suBicienUy loa+Impedance and having aut(i-
(F'PN): Eionding atl piping and metel air duots within ihe premises wiil prwide cient cunrent-carryiog capacity to.prevent the buildnp of wltages that may result!tt
additiona!safety. , , undue hazard to connected eqwpment or to peisons.
H:Qrour�d(n �lectrode S stem tc) Concrete-Encaaed Electrode..An electrade enr,ased lry at least 2
9 Y inches(50.8 mm)of concrete,.located within and near the bottom of a oon-
crete faundation or foating that is in direct vontad with the.earch,cor►sist-
250-81. GroundMg Eleotrode System. If available on the premises at �g of at leasf 20 feet (6.1 m)of one or more bare or zinc galvanized or
each buitding or structure served,each item(a)through(d)below,and anyf other electrically conductive coated steel rein#'orcing bazs or rods of not
made electrodes in accordance with Sections 25t}-83{c) and (d), shall be less than �!x inch {12.T mm) diameter, or consisting of.at least ?A feet
bonded together to form the grounding electrode systern. Interior metal' (6.1 m)of bare copper conductor not smaller than No.4.
water p►ping located more than 5 feet(152 cm)from the point of entrance
to the building shall not be used as a conductor to intercannect the eleo- (d) around Ring. A graund ring encircling the building or structure, in
trodes and the grounding electrode conductor.T'he banding jumper shatl be di�ed contact with the earth at a depih below esrth surface not less than
installed in accordance with Sections 25Q-92(a) and (b}, sl�all.be sized in 2�z feet{762 mm},cansisting of at least 20 feet(6.1 m)of bare copper con-
accordance with Sectioa ZSO-94, and shalt be connected in the manaer� ductar nat smaller than No.2.
specified in Section 250-115.The unspliced grounding electrade conductor 25�. Made and.Other Eleetrodea. Whete none of the electrodes s c
shall be perznitted to run to atry comtenient g,rounding electrade available ��ed in Section 250-81 is available one or raore of the electmdes s ec��fied
in the grounding ele�trode system.It shal!be sized for the largest ground- +
ing electrode conductor requ�red among aIl the available electrodes, i�(b)through(d}belaw shall be nsed.Where practicable a�ade etectrodes
Fxceptivn No. 1: It s/ralt be persnitted to splice the gir�unding etectmde shall be embedded belaw perrmanent moisture level.Mac�e etectrodes shall
coruluctor 6y means af irr�versible cvri�r�essron-type cora:ectors listed for be free f�om nonconductive coatings,such as paint or enamel.Where more
the purpose or the exotl�emuc weldptg process. than one eleetrocie is used,eaGh electmde af gne gmundi�g�ystem{includ-
ing that used for lightning rods)shall not be less than 6 feet(1.83 m)from
F.�rce,ption No. 2: Xn iredustnal and commercial buitdings wlYer�co�rdi- any other elecfrode of another grownding system. '
tiorts of rrrarnter:ance ond supetvision errsux�that ar�y quatcfed persorrs �FPN): ltvo or more etecirodes that are eff+ectively bonded togtthe�r are to be
will service the i�rstalXatuan and the entire length of the interiar metal water treated as a singlo electmde system in Wis seuse. ,
,pipe Htat is being used for the conductor is e�osed. � �
(FP3Vj: See Section 547-8 for specia!groundin�and bonding requirements far � �a) Metel Underground Gefi Piping Syst9m. A metal underground gas
agnc�uurel b�ild��ga. piping systern shall not be used as a grounding electrode.
(b) Other lacat Metai Undergmund Syatem�►or Structurea. Other local
(a) Metal Undergrqund Water Plpe. A metal und'erground water pipe in meka! underground systems or sWctutes, sach�as,piping systems and
direct contact with the earth far 10 feet (3.QS m} or more �including any undergraund tanks. �
metai well cas6ng eft'ectively bonded ta the pipe)and eleekneally continu-
aus(or made electrically continuous b�+bonding azound insulating joints or �cj Rod ai�d Flpe Electrodes. Rod anci pipe electrodes shall nat be less
sections or insulating pipe}.to the potnts af c:annectian of the grounding than 8 feet(2.44 m)in length and shall consist of the following materials,
electrode conductor and the bondin�conductors,Continuity of the ground- and shall be installed in the fallowing manner:
ing path or the bonding connection to mterior pipiung shall not rely an water (1) Electrodes of pipe or conduit shall not be amalter than�jd-inch trade
meters. A metal undergcound water pipe st�all be supplemet�ted by an size and,where.of iron or steel,shal!have the outer st�rface galvan�ed or
additianal electrode of a type specified in Section 25U-81 or in Section 750- othetwise metal-ccrated for canosion protecdon. '
83. The supplementat electrode shall b� pernutfed to be bonded to ths (2) Electmcles af rods of.iron or steel shall be at teast�'s inch(25.87 mm)
grounding eiectrode c�ndactor, the graunded service-entrance conductor,).� diamater. 3tainless steel rads�less than�'e inch{15,$?ITSz�1� it�dialrietCCi
the grouncled service raceway,or any graunc�ed service enclosure. �nonferrous zods,or their equivalent shall be listed and shall not be less than
Wt�te the supplennental electxode is a made electrode as in Section 25Q- yz�ch(12.7 mm)in diameter. '
83{c}ar{d},that portion of the banding jumper Ehat is the sole connection {�j �e electrale sha11 be installed such�that at least 8 feet(2.44 rt�)of
to the supplemental�rounding electrode shall not be required to be larger ���gth is in contact with the soi1. It shall be driven to a depth Qf not less
than No.6 copper wtre or No.4 aluminum wire. � than 8 feet (2.44 m) except that,where rock botlom is encountered, the
Exce,�tion: 77ie su�plenrentat elecmi�fe shatt be penr�itted to be bor►derX�electrode sliait be daven at an oblique angle not to eaceed 45 degtees from
tv tl:e rr:terior metal water piping at a�:y cot:venient poir:t as cover�d ii: the vertical or shall be buried in a trench that Is at least 2�l2 t'eet(762 mm)
Sec�ion 250-81, Fxceptian No. 2. • deep.Tlie upper end nf the electrode shall be 8ush with or betaw ground