LFNC as riser for lateral service

[vango]

230.43 (16) Service entrance conductors Wiring Methods for 600 Volts, Nominal, or Less...
allows Liquidtight flexible nonmetallic conduit, with regards to 300.5 (D)(1)
Utility standards (and local AHJ) have required schedule 80 PVC or RMC forever and a day.
Technology and products perpetually change, but safety must remain constant.
Below the meterbase exists 4' of UV rated/direct burial 2" LFNC with an 18"long 2.5" slip sleeve up from ground level for
additional protection. I am in need of professional opinions.

 

[suemarkp]

What is your question - the utility used LFNC and you don't like that, or you used LFNC and the utility or inspector won't let you?

The service lateral may be upstream of your service delivery point. If so, the NEC doesn't matter and its what your POCO says that matters (which is usually consistent with the NESC, but local rules could vary just like local areas adopt changes to the NEC).

Here in WA, we can't use EMT for Service Conductors.

Also, what are these conductors really (where is the Service Delivery Point)? You may want to see 230.30 if these are the service lateral, but still under NEC purview.

Finally, What is acceptable for protection from physical damage can be debated between you and the inspector as many times it isn't clear cut. But sch 80 PVC or RMC should be approved without question. Are these conductors direct bury rated, or something thinner meant for a raceway?

 

[vango]

Hey Suemarkp, the question actually is asking for opinions of using LFNC uv/direct burial rated for protection of lateral service conductors at the penetration from underground to the bottom of the meter base. The POCO uses polytube and urd xhhw-2 Al for their underground. The line side lugs of the meter base would be the POS. The AHJ, POCO, and the NEC are willing to allow this practice "where not subject to damage" (define subject to damage).

NEC 2011
230.43 (16)
230.50 (A)
possibly table 300.5 col 3

and yes I agree the POCO should have the task placed to them however, our POCO requires the customer to purchase the required materials and has shown acceptance of uv/direct burial LFNC rated conduit for the ease of installment when the stub up requires an offset to align with the meter base, also applying an 18" slip sleeve starting at grade level up.

The NEC is "gray" about the definition of "subject to damage" and therefore pushes the responsibility of the definition to the AHJ and the POCO. If you were allowed to use this wiring method, would you use it for a single phase 120/240 residential system?

 

[suemarkp]

Yes I would if that service is in a somewhat protected area (e.g. can't get hit/scraped by cars and trailers). I see a fairly tough cable to start with (direct bury), a LFNC protection sleeve, and an additional protection sleeve at the lower 18". I don't have long term experience with LFNC though, so I don't know how it will look in 30 years of sun exposure. But even rigid PVC gets brittle over time.

I see the biggest risk under the dirt from possible shovel hits. How far down does that sleeve and LFNC go? How deeply buried are those service conductors? If 30" down and the LFNC goes most of that distance, I wouldn't worry.

Comments from others may be more useful, as most of what I see is built over code and implemented by paranoid people.

 

[don_resqcapt19]

...
The NEC is "gray" about the definition of "subject to damage" and therefore pushes the responsibility of the definition to the AHJ and the POCO. If you were allowed to use this wiring method, would you use it for a single phase 120/240 residential system?

You said the service point is the line side of the meter...the NEC does not apply to the part of the installation that you are talking about. The power company is the AHJ for that part of the installation.

 

[vango]

I agree Don.
If your one and only utility company required the customer to purchase this equipment, and the utility company was acceptable to LFNC use, would you use it or not and why?

 

[don_resqcapt19]

I agree Don.
If your one and only utility company required the customer to purchase this equipment, and the utility company was acceptable to LFNC use, would you use it or not and why?

It is just a damage issue. The LFNC conduit provides a fair amount of protection, and you have a sleeve for the first 18". I really don't see an issue. It is my opinion that the LFNC provides about the same protection as schedule 80 PVC.

I can't imagine that the utility specifically requiring that installation. I could understand them permitting it, but I don't understand them requiring it.

 

[vango]

sorry, didn't mean requiring LFNC. just preferring LFNC where odd angle stub ups appear necessitating offsets particularly after the concrete has been poured. The real problem is simply poor communication between the builder, electrical contractor, and utility company.