300.5 note 2

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mcclary's electrical

Senior Member
Location
VA
Looking for explaination to note #2 of article 300.5 minimun cover requirements. When is it used? :confused:



If you have a raceway that needs to be buried and meet fill requirement, but it cannot be due to rock, then code permits using 2 inches of concrete with metal burial rated conduit. Unless I'm reading it wrong, it makes more sense to read note 5 before note 2.
 

hotwire1955

Senior Member
Location
nj
If you have a raceway that needs to be buried and meet fill requirement, but it cannot be due to rock, then code permits using 2 inches of concrete with metal burial rated conduit. Unless I'm reading it wrong, it makes more sense to read note 5 before note 2.

note #2 is in reference to a 2 inch envelope and note#5 is for 2 inch of concrete over conduit metal or nonmetalic extending down to rock.:confused:
 

volt101

Senior Member
Location
New Hampshire
When a conduit is going to be encased in concrete anyways, a conduit that is listed for burial only when concrete encased will normally be used. This conduit that is listed as such is of a schedule less then 40, that is, it is cheaper due to the fact that the pipe is very thin. This note sets the rules.
 

raider1

Senior Member
Staff member
Location
Logan, Utah
Note #2 is in reference to Type A and Type EB PVC and HDPE conduit. This type of conduit is listed for underground use only where encased in concrete.

Here is what the UL White book has to say about this type of conduit.

RIGID NONMETALLIC UNDERGROUND CONDUIT, PLASTIC (EAZX)
Rigid Nonmetallic Underground Conduit, PlasticEAZXUSE AND INSTALLATION
This category covers plastic types of rigid nonmetallic conduit, including straight conduit, elbows and other bends in sizes 1/2 to 6 (metric designators 16 to 155) inclusive, intended for installation underground as raceway for wire and cable in accordance with Articles 352 and 353 of ANSI/NFPA 70, "National Electrical Code" (NEC). This conduit may be: (1) polyvinyl chloride (PVC) Type A, Type EB or Schedule 40, or (2) high density polyethylene (HDPE) Schedule 40, Schedule 80, EPEC A, EPEC B. This conduit is intended for installation and use in accordance with the following information.
The conduit is intended for underground use under the following conditions, as indicated in the Listing Mark: (1) when laid with its entire length in concrete in any location (Type A), (2) when laid with its entire length in concrete in outdoor trenches (Type EB) and (3) direct burial with or without being encased in concrete (HDPE Schedule 40, Schedule 80, EPEC A, EPEC B or PVC Schedule 40). The conduit is intended for use in ambient temperatures of 50?C or less.
Unless marked otherwise, Type A and HDPE Schedule 40, Schedule 80, EPEC A, EPEC B conduit is intended for use with wire rated 75?C or less. Type EB and Type A conduit, where encased in concrete in trenches outside of buildings, may be used with wire rated 90?C or less. HDPE Schedule 40, Schedule 80, EPEC A, EPEC B or PVC Schedule 40 conduit, when directly buried or encased in concrete in trenches outside of buildings, may be used with wire rated 90?C or less.
Where conduit emerges from underground installation the wiring method shall be of a type recognized by the NEC for the purpose.
PVC conduit is designed for joining with PVC couplings by the use of a solvent-type cement. HDPE conduit is designed for joining by threaded couplings, drive-on couplings, or a butt-fusing process. Instructions supplied by the solvent-type cement manufacturer describe the method of assembly and precautions to be followed.

Chris
 
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