Failed inspection today??????

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bighills

Member
Location
Mooresville NC
8" deep trench.... 3/4 rigid from back of house to shed..... Inspector says check 300.5 column 4, should be 12"..... I always thought 6" and column 2.....Is he wrong?
 
I see nothing wrong. NEC 300.5 column 2 seems right. He might know something we dont. But if its in rigid conduit 300.5 column 2 seems to be right. 300.5 column 4 is only good for 120v or 20 amps, what voltage you running out to the garage?
 

tryinghard

Senior Member
Location
California
8" deep trench.... 3/4 rigid from back of house to shed..... Inspector says check 300.5 column 4, should be 12"..... I always thought 6" and column 2.....Is he wrong?
Not always column 2 - read column 4
Column 4 Residential Brach Circuits Rated 120 Volts or Less with GFCI Protection and Maximum Overcurrent Protection of 20 Amperes
If yours meets this criteria it's 12". If yours is 240V then it's 18" (interesting?)
 

ceb58

Senior Member
Location
Raeford, NC
8" deep trench.... 3/4 rigid from back of house to shed..... Inspector says check 300.5 column 4, should be 12"..... I always thought 6" and column 2.....Is he wrong?

Have the inspector explain note 4 of table 300.5
"wiring methods types listed in columns 1-3 is used for one of the circuit types in column 4 & 5 the shallowest depth of burial shall be permitted"

So by this even if it is a method used in column 4 it will allow the depth of column 2 which would be 6''
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
Have the inspector explain note 4 of table 300.5
"wiring methods types listed in columns 1-3 is used for one of the circuit types in column 4 & 5 the shallowest depth of burial shall be permitted"

So by this even if it is a method used in column 4 it will allow the depth of column 2 which would be 6''

I disagree-- 12" would be the shallowest depth if it is RMC under a driveway and then only if the circuit is 120V or less.... as stated in col. 4 otherwise col.2 applies.

IMO, the shallowest depth applies to the 2 choices of depth in the row that you are using not the entire table. Otherwise 0" would be legit

The op stated in another forum that it is not under a driveway so 6" is appropriate.
 
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tryinghard

Senior Member
Location
California
In light of note 4 I understand it as there are 2 possible choices in the "One - and two - family dwelling" row 18" or 12". With this I believe the criteria of column 4 would have to be met entirely before its 12" would count, and if this criterion is not met 18" would apply.

BUT

Maybe I do not understand the table row definitions, is this row only for residential driveways and parking areas? If it is and the two former items do not apply then the top row “All locations not specified below” would be used and the comparison really is 6” vs 12”, that’s bizarre a 240v feeder would be 6” with no Note 4 issue at all (higher voltage shallower ditch lower voltage & GFCI protected deeper ditch??).
 
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hurk27

Senior Member
In light of note 4 I understand it as there are 2 possible choices in the "One - and two - family dwelling" row 18" or 12". With this I believe the criteria of column 4 would have to be met entirely before its 12" would count, and if this criterion is not met 18" would apply.

BUT

Maybe I do not understand the table row definitions, is this row only for residential driveways and parking areas? If it is and the two former items do not apply then the top row “All locations not specified below” would be used and the comparison really is 6” vs 12”, that’s bizarre a 240v feeder would be 6” with no Note 4 issue at all (higher voltage shallower ditch lower voltage & GFCI protected deeper ditch??).


The rows are the location of the buried conductors, the columns 1-3 are the type of wiring method, 4&5 are special allowance for circuits that meet these columns requirements, in no case does column 4 or 5 require a deeper depth the 1-3, as it is design to give relief from these depths not add to them, so knowing this we can understand the #4 note, if you have a 20 amp circuit feeding this shed fed by UF cable going out through the back yard not under any driveways or parking spaces, then row 1 will tell us that we need to bury this cable 24" if it is a GFCI protected circuit then column 4 kicks in and allows us to reduce this to 12" same thing in column 3 row 1, 18" without, 12" with GFCI protection, now because column 2 is RMC it has a shallower burial depth then column 4 requires, note 4 kicks in and tells us to use the less of the two which is 6"

Only work in the column and row that applies to your installation, then add 4 or 5 if it applies, or you will confuse yourself.

Inspector is incorrect.
 
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tryinghard

Senior Member
Location
California
The rows are the location of the buried conductors, the columns 1-3 are the type of wiring method, 4&5 are special allowance for circuits that meet these columns requirements, in no case does column 4 or 5 require a deeper depth the 1-3, ...Only work in the column and row that applies to your installation, then add 4 or 5 if it applies, or you will confuse yourself.

Inspector is incorrect.

Got it columns 4 & 5 are considered only if met, 240V will not meet these two.
 
Inspectorfabs

Inspectorfabs

300.5 state's the "type of wiring method or circuit" then colum 2 would be applied to this installation as all locations not specified below the depth would be 6". The other colum's are for the special use of that application being installed.The AHJ is wrong .
 

Hutch708

Member
Location
NC
I am the inspector, and I was wrong. I called the contractor and told him so. I also told him that Mike Holt was a good place to ask his question because this inspector found it while researching his concerns.
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
I am the inspector, and I was wrong. I called the contractor and told him so. I also told him that Mike Holt was a good place to ask his question because this inspector found it while researching his concerns.

Thank you for being willing to accept you made an error. So many inspectors will not listen to anyone else.

istockphoto_5604144-thumbs-up.jpg
 

hurk27

Senior Member
I am the inspector, and I was wrong. I called the contractor and told him so. I also told him that Mike Holt was a good place to ask his question because this inspector found it while researching his concerns.

I wish we had more inspectors around my area like you, my job would be so much easier, I see you joined back in 08 but Welcome to our little world anyways:)
 

eprice

Senior Member
Location
Utah
8" deep trench.... 3/4 rigid from back of house to shed..... Inspector says check 300.5 column 4, should be 12"..... I always thought 6" and column 2.....Is he wrong?

We don't have enough information to answer the question. By "3/4 rigid" do you mean rigid metallic or rigid nonmetallic? And, as Augie asked, any drive way or parking areas involved?
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
We don't have enough information to answer the question. By "3/4 rigid" do you mean rigid metallic or rigid nonmetallic? And, as Augie asked, any drive way or parking areas involved?


There is no driveway involved and I am quite certain it is RMC.
 
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