Tracer Wire

[JFletcher]

Is there any NEC code(s) that cover installing tracer wire (in this case, on underground PVC conduit)? Size, type, how run, strapping, etc, etc? Also is warning tape required on buried conduits, or is that a POCO thing? Job spec didnt mention either, construction mgr wants tracer wire; verbal change order I suppose. Yes, we should get that in writing.

 

[iwire]

I do not know of any code requirements regarding those things.

We often use detectable warning ribbon for this.

https://www.bradyid.com/en-us/91601/prod-2070414.html?cat=BRID2048899

 

[JFletcher]

I do not know of any code requirements regarding those things.

We often use detectable warning ribbon for this.

https://www.bradyid.com/en-us/91601/prod-2070414.html?cat=BRID2048899

Thank you. How would you run this tape 4-6" below the surface when the conduit is 18" deep? Backfill some, then run the tape at the recommended depth? Obviously strapping it to the conduit is out. Would that tape break under backfill weight, or does it matter if it's continuous?

I dunno how Miss Utility or equivalent (snccomm here) would miss a load of copper in a PVC pipe, but I dont line-detect for a living. This is a first for me.

 

[ptonsparky]

I thought marking tape was required for buried SE conductors. Conduit or DIrect bury. 12" above. Not that I measure exactly.

Tracer wire is not required, but some here use a tracer tape. It would aid in finding the empty raceways.

 

[Sierrasparky]

I thought marking tape was required for buried SE conductors. Conduit or DIrect bury. 12" above. Not that I measure exactly.

Tracer wire is not required, but some here use a tracer tape. It would aid in finding the empty raceways.

It also helps in finding conduits that have their conductors off at the time of tracing. I see that common area night lighting that is switched always gets dug up.

 

[infinity]

I thought marking tape was required for buried SE conductors. Conduit or DIrect bury. 12" above. Not that I measure exactly.

Tracer wire is not required, but some here use a tracer tape. It would aid in finding the empty raceways.

The NEC requires it for direct buried SE conductors.

 

[ptonsparky]

The NEC requires it for direct buried SE conductors.

Yes, 300.5(D)(3).

We are allowed to use Sch 20 conduit for rodent protection. The conductors are required to be DB rated when we do. Personal preference extended that to all buried PVC containing SE conductors, not that the tape will save them from a trencher being run by someone that did not call for a locate to begin with.

 

[kwired]

Grounded/grounding conductors installed within the raceway make a good tracer wire without even having to disconnect anything - most of the time.

If you are using a passive locator you do need an energized line - it is searching for the 60Hz of an energized line, if the line is not energized then you need a direct connected device to put a trace signal on the line.

 

[ggunn]

Yes, 300.5(D)(3).

We are allowed to use Sch 20 conduit for rodent protection. The conductors are required to be DB rated when we do. Personal preference extended that to all buried PVC containing SE conductors, not that the tape will save them from a trencher being run by someone that did not call for a locate to begin with.

Or a fencing company. On a ground mounted PV system I worked on a few years ago we ran USE in a trench with marking tape and flags, and some settling of the backfill made the trench location very obvious. It did not deter the fencing company from poking a hole for a post right through our conductors. The fence was supposed to protect our installation.

 

[Fulthrotl]

Is there any NEC code(s) that cover installing tracer wire (in this case, on underground PVC conduit)? Size, type, how run, strapping, etc, etc? Also is warning tape required on buried conduits, or is that a POCO thing? Job spec didnt mention either, construction mgr wants tracer wire; verbal change order I suppose. Yes, we should get that in writing.

what i've normally done is use 3" wide warning ribbon that will show up with underground locators.
i'll put it a foot above the conduits.

 

[Fulthrotl]

It also helps in finding conduits that have their conductors off at the time of tracing. I see that common area night lighting that is switched always gets dug up.

i've an entire parking lot that it seems has had the home run cut at some point in
the past.

my quote was for new LED heads on the poles. i excluded any issues with feeder
wiring in disrepair. i was assured that "it was fine". it's not fine. nine new heads on
poles, one works.

anyone here have a brand of locator they are fond of that works well on saw cut stuff
buried in the ground? i'll need to go outward from the panel till it stops, then hit the
most likely pole, and work backwards. then dig a hole.

suggestions on a good underground locator, please?

 

[kwired]

i've an entire parking lot that it seems has had the home run cut at some point in
the past.

my quote was for new LED heads on the poles. i excluded any issues with feeder
wiring in disrepair. i was assured that "it was fine". it's not fine. nine new heads on
poles, one works.

anyone here have a brand of locator they are fond of that works well on saw cut stuff
buried in the ground? i'll need to go outward from the panel till it stops, then hit the
most likely pole, and work backwards. then dig a hole.

suggestions on a good underground locator, please?

You need a fault locator, a cut line is like a faulted line at the fault point, unless you have good isolation from earth with the end of the conductor. Usually if the end is that clean you will have fairly definite loss of signal with a tracer locator at the end though.

I have a Rycom instrument (though it is maybe 30+ years old) that is both a tracer and fault finder. I think same company still makes a similar unit today though.

 

[ptonsparky]

I think Kwire and I have similar units, different name.

They will find faults under concrete slabs if you tie sponges to the probes soaked in a salt water mix.

Or or you can get those that tell you the depth as well. Quicker than an apprentice with a shovel

 

[JFletcher]

It also helps in finding conduits that have their conductors off at the time of tracing. I see that common area night lighting that is switched always gets dug up.

Interesting. I figured they used fancy metal detectors that would pick up copper, energized or not, and only non-metallic pipe (like for chiller lines, or pvc water line) would need tracer wire.

fullthrottle, I suppose you backfill some, lay tape, finish backfill?

Tape seems better as it's a more visible indicator. And it's good to know (after the fact) that red and silver foil stuff wasnt more trash in the ground, but protecting a 12,470 service (I knew the primary was there, just not what the tape was). :slaphead:

 

[Fulthrotl]

Interesting. I figured they used fancy metal detectors that would pick up copper, energized or not, and only non-metallic pipe (like for chiller lines, or pvc water line) would need tracer wire.

fullthrottle, I suppose you backfill some, lay tape, finish backfill?

yup. the only stuff i've done recently was 4' deep in two sack sand
slurry... slurry, put down 1' sand, mylar ribbon, 2' of sand.......

the guys i was doing the work for had the surveyor shoot the ditch
on top of the slurry. saves a lot of guessing later. top of the duct bank
is right on the as builts. none of this stuff is remotely accessable once
the job is done.. it's currently under 60' tall piles of sand and aggregate
in a gravel terminal.

*can you move that pile a bit so i can get to that pipe, please?*

 

[kwired]

I think Kwire and I have similar units, different name.

They will find faults under concrete slabs if you tie sponges to the probes soaked in a salt water mix.

Or or you can get those that tell you the depth as well. Quicker than an apprentice with a shovel

I wasn't aware of the sponge idea to find a fault under concrete.

To find depth with this unit you first locate and mark the path, then hold the probe at a 45 degree angle and locate it again, mine has a 45 degree turn in the probe handle for that reason. If you are standing in line with the conductor being located and could have a cross sectional view of what is below grade you draw a right triangle with two 45 degree corners. One side is between the conductor and the mark at the surface directly above, the other side is between your two marks on the surface, the distance between those marks is same as the depth because both non hypotenuse sides of 90, 45, 45 degree triangle are the same length.

You may not be able to say it is precisely 32 inches deep, but you have a pretty good idea that is probably within 6 inches or so as long as you hold the probe reasonably close to plumb/45 degrees for each locate method.

 

[ptonsparky]

I wasn't aware of the sponge idea to find a fault under concrete.

To find depth with this unit you first locate and mark the path, then hold the probe at a 45 degree angle and locate it again, mine has a 45 degree turn in the probe handle for that reason. If you are standing in line with the conductor being located and could have a cross sectional view of what is below grade you draw a right triangle with two 45 degree corners. One side is between the conductor and the mark at the surface directly above, the other side is between your two marks on the surface, the distance between those marks is same as the depth because both non hypotenuse sides of 90, 45, 45 degree triangle are the same length.

You may not be able to say it is precisely 32 inches deep, but you have a pretty good idea that is probably within 6 inches or so as long as you hold the probe reasonably close to plumb/45 degrees for each locate method.

That is what we do on occasion when some one asks but with no guarantee.

We do have a 4' probe.:thumbsup:

 

[kwired]

That is what we do on occasion when some one asks but with no guarantee.

We do have a 4' probe.:thumbsup:

The locator guys that some of the communications companies send out for one call locates won't tell you how deep their lines are even though they have a unit that has digital display that tells the depth, I suppose this is a CYA thing. I have been on site a time or two when they show up and if you ask how deep it is they won't tell you but may let you look at the display "for your own interpretation".