300.50 cover requirements

[ddavi280]

The way I interpret the cover requirements for special condition 6 for a 12470 Volt feeder is that if I have 6 inches of concrete cover I can reduce my 24 inches down to 6" (-18" per note 3). So if you goto note a , cover is defined by the distance from the top of the pipe to finished grade. I am inclined to include this 6 inches of concrete in that cover calculation. Am I off base? It seems pretty black and white to me. Any input appreciated.

 

[sparkyboys]

what is this special condition 6, i do not see it.

 

[chris kennedy]

Go all the way to the right of T300.50.

 

[ddavi280]

subject to vehicular traffic, far right column of table.

 

[sparkyboys]

you mean column 5, thats for 30v, not 12470v
column 4...max ocpd...20 amps

i think its still 24"

 

[Dennis Alwon]

what is this special condition 6, i do not see it.

He said Note 3.

 

[chris kennedy]

Go to 300.50, not 300.5.

OP, what wiring method are you using?

 

[sparkyboys]

thats no vehicle traffic, what is this wire for?
ohhhhhhh .50

 

[ddavi280]

So you have a clear picture of what we have... Finished grade will have 1 inch of asphalt followed by 6 inches of concrete to the top of my conduit. (which can't go any deeper due to conditions).

 

[ddavi280]

2008 code 300.50 far right column is for areas subject to vehicular traffic. This is a 12470 volt feeder for for several buildings on a University Campus. (future feeder actually but still applies).

 

[sparkyboys]

300.50

300.50

under special 6 is 24". there is no general note for special 6

 

[sparkyboys]

vehicle traffic, now go back to t3oo.5, under streets highways roads alleys driveways and parkinglots....24"

 

[ddavi280]

Note 3 applies generally to the whole table including column 6.

 

[chris kennedy]

under special 6 is 24". there is no general note for special 6

Then I would wonder what the "General Notes" 1-3 apply to?

 

[Dennis Alwon]

So you have a clear picture of what we have... Finished grade will have 1 inch of asphalt followed by 6 inches of concrete to the top of my conduit. (which can't go any deeper due to conditions).

I would say that note 3 allows you to reduce the trench from 24" to 6" if there is 6" of concrete over it but I still think that means you need 6 inches below the concrete. Also Note 3 states for industrial establishments. I am not sure whether a univ. would meet that criterion.

 

[ddavi280]

300.5 in no way applies to this situation due to voltage being over 600V.

 

[Dennis Alwon]

Then I would wonder what the "General Notes" 1-3 apply to?

I think those are general notes and apply to any of the conditions above.

 

[sparkyboys]

isnt a university commercial, not industrial.

 

[ddavi280]

I would say that note 3 allows you to reduce the trench from 24" to 6" if there is 6" of concrete over it but I still think that means you need 6 inches below the concrete. Also Note 3 states for industrial establishments. I am not sure whether a univ. would meet that criterion.

Your following my question perfectly! This is the point I want to discuss. If you read note (a) cover is defined clearly as top of pipe to finished grade. No where does it say "in addition to the concrete" from what I see. Therefore I feel the concrete counts as the 6" of cover over the top of pipe.

 

[chris kennedy]

I think those are general notes and apply to any of the conditions above.

:grin: Really...