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Warning Ribbon 12" Above Service Conductors

jar546

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OK, I was recently schooled on this by a co-worker and realized that I had been enforcing something that I always saw as standard practice even though it is not actually required under NEC 300.5.

Who enforces this when the service conductors are in conduit and are not direct burial conductors?
 
(D) Protection from Damage. Direct-buried conductors and cables shall be protected from damage in accordance with 300.5(D)(1) through (D)(4).


(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.

It seems odd that no ribbon is required until the cable depth is 18" or more. What seems damned strange is burying a bare cable at any depth. In all of my weeks as an inspector I've not encountered that.
 
(D) Protection from Damage. Direct-buried conductors and cables shall be protected from damage in accordance with 300.5(D)(1) through (D)(4).


(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.

It seems odd that no ribbon is required until the cable depth is 18" or more. What seems damned strange is burying a bare cable at any depth. In all of my weeks as an inspector I've not encountered that.

In PA I saw direct burial conductors a lot, especially for long runs and that is when the tape marker 12' above is actually required. This section is applicable to service conductors and most POCOs require 36" depth anyway so the requirement kicks in.
 
Got it! (D) is saying (3) only applies to direct buried service conductors and the warning ribbon is one of the methods listed for protection.

To humor here are some different interpretations from a "celebrity" author and another official interpretation of the NEC.

Article 300
Wiring Methods

300.5 Underground Installations

Replace the word “service laterals” with “service conductors,” so that this section now reads:

(D) Protection from Damage.
(3) Service Conductors. Service conductors (in a raceway or cable, or exposed) that are not encased in concrete, but are buried 18 in. or more, must have their location identified by a warning ribbon placed at least 12 in. above the underground installation.

Intent: The intent of this editorial change, was to clarify that a warning ribbon is required for service conductors (exposed or in a raceway) buried more than 18 inches.

Author’s Comment: Often service lateral conductors are installed in nonmetallic conduit (which must have 18 in. of cover [Table 300.5]) by the electrical contractor; therefore, a warning ribbon must be placed at least 12 in. above the underground raceway.

300.2(D).JPG
 
To drive this home even further, here is a ruling by the code panel when someone wanted to change the code to required it for conductors in conduit.

Screen Shot 2019-04-04 at 22.16.16.png
 
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