Does the NEC address minimum coverage requirements for low voltage concrete-encased conduit? Table 300.5 seems to apply only to direct-buried conduits, and Figure 310.60 applies to medium voltage conductors. I have a 480V ductbank that was designed for 18" minimum coverage, but field conditions necessitate a shallower installation. I'm trying to determine if there are Code implications. . . .
Minimum Ductbank Cover
- Thread starter msteiner
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chris kennedy
Senior Member
- Location
- Miami Fla.
- Occupation
- 60 yr old tool twisting electrician
msteiner said:
If your duct bank meets these conditions and or you pour a slab over the bank then your looking at 4" cover IMO.
Chris - I guess I buy the argument that the concrete in the ductbank could consitute the 4" thick slab required by T300.5, but I wouldn't think an additional slab over top of the ductbank would be required. If I understand you correctly, that seems to be what you're suggesting.
chris kennedy
Senior Member
- Location
- Miami Fla.
- Occupation
- 60 yr old tool twisting electrician
Is a duct bank a slab?msteiner said:
I can tell you I don't know of any inspector around here that would have a problem if I showed him the job site conditions and detail of the duct bank.
Your OP didn't say if these were service laterals or feeders with OCP. That could make a difference.
charlie
Senior Member
- Location
- Indianapolis
This also depends on how thick the concrete is on the top of the duct bank. I have seen some pretty thin pours for some reason. :-?
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