3-37 Log #1465 NEC-P03
(300-5)
Final Action: Reject
Submitter: Jamie McNamara Hastings, MN
Recommendation:
I underlined added text and put a strike through deleted text.
"300.5 Underground Installations..."
(D) Protection from Damage. Direct-buried conductors and cables shall be protected from damage in accordance with (1) through (4) (5).
(1) Emerging from Grade. Direct-buried conductors and enclosures emerging from grade shall be protected by enclosures or raceways
extending from the minimum cover distance required by 300.5(A) below grade to a point at least 2.5 m (8 ft) above finished grade. In no
case shall the protection be required to exceed 450 mm (18 in.) below finished grade.
(2) Conductors Entering Buildings. Conductors entering a building shall be protected to the point of entrance.
(3) Service Conductors. Underground service conductors that are not encased in concrete and that are buried 450 mm (18 in.) or more
below grade shall have their location identified by a warning ribbon that is placed in the trench at least 300 mm (12 in.) above the
underground installation.
(3) (4) Enclosure or Raceway Damage. Where the enclosure or raceway is subject to physical damage, the conductors shall be installed in
rigid metal conduit, intermediate metal conduit, Schedule 80 rigid nonmetallic conduit, or equivalent.
(4) (5) Listing. Cables and insulated conductors installed in enclosures or raceways in underground installations shall be listed for use
in wet locations.
"(E) ?"
(G) Service Conductors. Underground service conductors that are not encased in concrete or in metal conduit and that are buried 450
mm (18 in.) or more below grade shall have their location identified by a warning ribbon that is placed in the trench at least 300 mm (12
in.) above the underground installation.
Substantiation:
To require nonmetallic conduits (PVC) containing service conductors to have an identification ribbon. When excavating around
nonmetallic conduits, the conduits and the conductors inside are often damaged and striped, exposing the excavator to hazards, before
being recognized as conduit and conductors.
Panel Meeting Action: Reject
Panel Statement:
The first method of protection of service conductors should be prevention and this can often be accomplished by first finding the
location of the conductors using a locator tool. Once that is accomplished then the backhoe or trencher operator has an idea that there
are service conductors in the location of the dig. Direct buried service conductors are much more easily damaged, even when the operator
is scratching the surface of the trench to locate the conductors, than when the conductors are installed in a raceway. The purpose of the
ribbon is to provide a marker so that the operator can then know the direct buried conductors are located six inches below that level.
The ribbon would not be of any use if the operator of the backhoe or trencher just started digging in the area without knowing if
anything at all is buried in that area, even if the conductors were enclosed in a steel or PVC raceway.
Number Eligible to Vote: 12
Ballot Results: Affirmative: 11 Negative: 1
Explanation of Negative:
CASPARRO: This proposal should be given further consideration. 300.5(D) applies only to direct buried conductors and does not
cover installations in raceways. A back hoe digging a trench can cause significant damage to underground raceways and the installed
conductors potentially exposing workers to a hazardous condition. I disagree with the panel statement that determining the location of
buried raceways and conductors should be solely dependent on the accuracy of a locator tool. The addition of a warning ribbon will
provide a physical means of early detection that could prevent serious injury to persons performing excavation work and should be
required.