Directional Boring Warning Ribbon

[Fred B]

NEC 2017, 300.5(D)(3) doesn't seem to have any exclusions to any specific way of underground wiring, but it is specific to service conductors. Does make sense from a safety perspective as service conductors have no or limited overload or fault protection for if it is struck in future excavations. Section also didn't say if it's easy then do it, if not, don't. Directional Boring of service conductors doesn't make it any safer from future excavation damage.

 

[ActionDave]

For the sake of every other electical contractor you need to politely escalate this up the food chain. The wording in the code is clear and the inspector is incorrect.

 

[hillbilly1]

NEC 2017, 300.5(D)(3) doesn't seem to have any exclusions to any specific way of underground wiring, but it is specific to service conductors. Does make sense from a safety perspective as service conductors have no or limited overload or fault protection for if it is struck in future excavations. Section also didn't say if it's easy then do it, if not, don't. Directional Boring of service conductors doesn't make it any safer from future excavation damage.

811! LOL!

 

[RichB]

" If directional boring can be done for the conductors then warning ribbon can be bored just above the Service Conductors. "

Is this even possible?

nope try pulling that mylar tape back through a hole and all you get is a hole full of bentonite with no tape

 

[winnie]

This inspector's interpretation is followed elsewhere.

For example:

https://www.dli.mn.gov/sites/default/files/pdf/eli_bulletin_ribbon.pdf

IMHO this is not a correct interpretation since 300.5(D) applies to _direct buried conductors_.

One work-around is to place the service point (and OCPD) where the conductors transition to underground.

-Jon

 

[wwhitney]

It is my opinion, any time the outer jacked of a cable or the conductor insulation is not in physical contact with the earth, the cable or conductor is not directly buried.

300.5(A) says "Direct-buried cable, conduit, or other raceways shall be installed to meet the minimum cover requirements of Table 300.5." Does that mean I can run conduit through a shallow buried chase, and then it is not direct buried, so I don't have to comply with Table 300.5?

Cheers, Wayne

 

[winnie]

Add:
300.5(D) doesn't apply, but the quoted text for 300.5(G) seems to apply to all service conductors including those in non-metallic raceway.

The limitation of 300.5(D) to direct buried conductors does not apply to 300.5(G).

The discussion of the CMP panel is at best confusing rather than adding clarity.

-Jon

 

[wwhitney]

300.5(D) doesn't apply, but the quoted text for 300.5(G) seems to apply to all service conductors including those in non-metallic raceway.

I don't follow. The "300.5(G)" quoted above was a proposed new code section that wasn't adopted.

Cheers, Wayne

 

[winnie]

300.5(A) says "Direct-buried cable, conduit, or other raceways shall be installed to meet the minimum cover requirements of Table 300.5." Does that mean I can run conduit through a shallow buried chase, and then it is not direct buried, so I don't have to comply with Table 300.5?

Cheers, Wayne

The term you are looking for is 'utility trench' and IMHO if you have a suitable raceway in a proper trench, you do not have a 'direct buried' installation, any more then if you had conduit attached to the side of a traffic tunnel.

See https://lockesolutions.com/product/electric-utility-trench/

-Jon

 

[winnie]

I don't follow. The "300.5(G)" quoted above was a proposed new code section that wasn't adopted.

Ahh. Apparently I was the one who did not follow

Thanks
Jon

 

[wwhitney]

The term you are looking for is 'utility trench'

Agreed on a utility trench, but how about if I just run some 2" PVC conduit sleeved inside, say, 4" corrugated pipe (solid)? If "direct buried" means "in contact with soil", then the PVC conduit is no longer direct buried, and per the wording of 300.5(A), it no longer needs to meet the cover requirements of Table 300.5.

I don't have much of an opinion on this one, just pointing out the perhaps unforeseen consequences of defining "direct buried" to mean "in contact with soil". Although I'm not sure how else you'd define it.

Cheers, Wayne

 

[don_resqcapt19]

" If directional boring can be done for the conductors then warning ribbon can be bored just above the Service Conductors. "

Is this even possible?

I consulted with two boring contractors before I did my proposal...they both said it would not be a problem, but they would not say they could place it exactly above the original bore.

 

[ptonsparky]

Learning from a bad experience, have them pull the HDPE. Hindsight, I should have bought a spool years ago.

For us, it doesn’t need to be UL as long as it does not enter the building and we use the correct fittings for conversion to PVC.

 

[ritelec]

No mention of boring may(?) be implying you don't install such "service" conductors that way. Service = Trench

I don't see how any municipal or utility inspector in their right mind would sign off on it.

I would think there should be other requirements for underground service as depth, sand, caution tape, eye ball so as the conductors aren't damaged to not even be considered to be installed by boring.

I'm in the inspectors corner.

Good post.

Trench it.

 

[Shockhoss]

I spoke to another inspector from a neighboring county, he understands the reasoning for this inspectors stance on the situation. He also recommended that to avoid this, find a way to put the service disconnect OCPD before the bore, and therefore changing it from being service conductors.

 

[ritelec]

wondering, why not trench?

 

[Shockhoss]

Trying to avoid tearing up the parking lot, this building is also close to some streets that may prove difficult to get shut down, not to mention the drop off that is at the corner of the property where the service pole is...

Thanks to this thread and some more research, we will discuss options and figure out the best solution, I will definitely report on which direction the project goes. And, everything we will be proposing needs to also pass the Historic building committee, since this building was built in the 1800's (another hurdle)

Thank you everyone

 

[hillbilly1]

I will definitely report on which direction the project goes.

That’s what they all say, then we are left hanging! LOL!

 

[ptonsparky]

Boring for the last jobs we did was $8 per foot. Very reasonable compared to others, but they took longer and weren’t near as prepared. I can rent a trencher for far less so there needs to be a good reason why not. In these instances, ‘don’t tear up the yard’!

 

[hillbilly1]

Boring for the last jobs we did was $8 per foot. Very reasonable compared to others, but they took longer and weren’t near as prepared. I can rent a trencher for far less so there needs to be a good reason why not. In these instances, ‘don’t tear up the yard’!

Most of the boring we have done is under parking lots, so much cheaper than repairing the asphalt a couple of times. ( no mater how well you tamp it, tractor trailer rigs will sink it)