Does an energized line always tone better compared to a non-energized line?

**FailedSafetyAudit** · March 6th, 2011, 07:19 PM

Does an energized line always tone better compared to a non-energized line?

Let's say you have 2 electrical power pole drops. One is active and goes to a single house. That house uses an average amount of electricity. Just the typical amount a normal family would require. This active power line is well grounded on both ends.

The 2nd drop from a different pole goes to a house that has been foreclosed on. There is no electricity flowing through the cable. This non-active power line is well grounded on both ends.

Would the energized line tone better just because it's energized? Would using an inductive clamp yield roughly the same signal quality? Would direct connecting to the outside power box or ground wire on the pole also be the same quality as compared to the non-energized line? How about general induction?

It's probably fair to say that the power passive mode wouldn't work as well on the non-active line, but why would Radio passive see any major differences in tone quality?

**ifinditunderground** · March 6th, 2011, 08:37 PM

Both services should locate the same regardless of the method as long as the conditiona of the lines and grounding is the same. The flow of current does not change how your radio signal is conducted by the aluminum conductors in the cables. Passive is a different monster, that may or may not work for either service line. The passive mode will work as long as there is a 60 Hz signal being carried by the conductors, whether it is thru the flow of current on the cables, or the re-radiation of 60 Hz by nearby active electric cables.

**Mke** · March 7th, 2011, 12:00 AM

I findit has nailed it again. The only thing I would add, would be the fact that there is enough variables in the equation when it comes to the passive modes of locating it is really hard to say for certian what results you would get between the energized and non energized cables. For example, I had a primary that was disconected on both ends, however, she still gave off the 60hz hum. However, I have walked across some active electrical lines, and have nothing show up on the 60cycle.

go figure

mke

**sundropmaster** · March 7th, 2011, 01:18 AM

Originally Posted by Mke

I findit has nailed it again. The only thing I would add, would be the fact that there is enough variables in the equation when it comes to the passive modes of locating it is really hard to say for certian what results you would get between the energized and non energized cables. For example, I had a primary that was disconected on both ends, however, she still gave off the 60hz hum. However, I have walked across some active electrical lines, and have nothing show up on the 60cycle.

That happens alot to me! I can get good power sweep on abandoned power rather than the new, and usually ill pick up the old power better than the new using direct connect. I have noticed for some reason sometimes with three phase the power passive sweep it kicks the signal 2 to 3 foot to the side of where is is actually add, and it happens when there is nothing there but the power

**DeadNutsOn** · March 7th, 2011, 01:54 AM

This a great question. Let me piggy back on this though with the above answers have me very confused.

How does this differ from Street Lights? Early on I was told if street lights are not energized they are difficult to locate but if you locate them when they are On they tone great. I have tried this in the past and this theory has held true many times.

Thanks for any answers on what I'm missing because Street lights tone when energized and don't do so well when not, in my experience.

**sprayandpray** · March 7th, 2011, 07:07 AM

The truth is there are Gremlins everywhere in the Locating World. Good signals that are 3 ft off, poor signals that are dead-on, and of course, no signal on a large 3-phase feeding a manufacturing plant that's drawing a massive amount of electricity. Then there's my favorite, signals that run to a structure and disappear underneath it without giving you a hint of what it is you are actually marking because you know it can't be the Secondary going to the bank of meters about 50 ft away.
Yes, these are some of the reasons I love this industry - you can learn something -or not-everytime you pull up on a jobsite, that is if you last long enough!

**ifinditunderground** · March 7th, 2011, 10:54 AM

Street lights are usually a terrible pain in the ass on or off. Get a Pipehorn, or Metrotech 530.

**headcipher** · March 7th, 2011, 02:12 PM

Originally Posted by sundropmaster

That happens alot to me! I can get good power sweep on abandoned power rather than the new, and usually ill pick up the old power better than the new using direct connect. I have noticed for some reason sometimes with three phase the power passive sweep it kicks the signal 2 to 3 foot to the side of where is is actually add, and it happens when there is nothing there but the power

I've found that 3 phase electric that is encased or caped with concrete has signal on either side of the encasement and none directly above. Next time you find this go on the other side of the duct and you will probably find the same off-set signal.
I have seen as well that some electric cables are so well shielded that it's difficult to get a signal on them. Case in point, I had an abandoned 34.5kv that ran great out of the switch cabinets, I only found the new line by checking with a power sweep. I found the new energized line was about 3 feet further into the lot. This was a new smooth jacketed and well shielded cable that I could only locate by induction. Turns out the old cable with the concentrics on the outside was still grounded.
I run into this more and more with the new cables.

**ifinditunderground** · March 7th, 2011, 05:27 PM

Originally Posted by headcipher

I've found that 3 phase electric that is encased or caped with concrete has signal on either side of the encasement and none directly above. Next time you find this go on the other side of the duct and you will probably find the same off-set signal.

Not entirely true, concrete ductbanks will typically center up on the approximate centerline of the bulk of the cabling inside. If all of the cables are on one side of the duct, and the other is empty conduits, your signal will center over the the cabling, not the duct. If the cabling is spread evenly within the duct, you will typically get the centerline of the duct, or within a couple of inches. There are of course many exceptions to this rule. If you are clamped on a specific cable within the duct, most likely you will center on this specific cable, especially if you are using low frequencies. if you are using high frequencies, many times you will bleed enough signal onto the other cables to have the same "centering" effect I described above. However, all that being said, if there is one conductor within the ductbank that is shallower (higher in the duct) and is a better conductor than all the rest, you'll find that the instrument will want to center on that conductor no matter what you are clamped on. Again, especially with high frequencies. Someone correct me if I'm wrong, but I've seen it time and time again while working behind a vac truck.

**Turk182** · March 7th, 2011, 06:35 PM

I have had some strange results with electric, including having a line tone 22" away from where it actually was, in four different frequencies in both peak and null.

**sundropmaster** · March 7th, 2011, 06:46 PM

I've seen the Power Cable in a huge hole, with no other utilities around, and i was looking right at the Power Cable and it put it off by 31 inches direct connect. The power in this area is in conduit all over! And from dealing with that and fibers in conduit also, they don't locate that great here, and the parts that the fiber are not in conduit(direct buried) it picks up with no problems. If I'm not mistaken. From what i was told, from the power company they cant fault find power in conduit. I get an off signal for the fibers also, but not as bad as the power. I just know that power sweep on power sometimes kicks the signal to the side, mostly with three phase. And I've seen them exposed and they are stacked tight together!

**ifinditunderground** · March 7th, 2011, 08:20 PM

Originally Posted by sprayandpray

The truth is there are Gremlins everywhere in the Locating World. Good signals that are 3 ft off, poor signals that are dead-on, and of course, no signal on a large 3-phase feeding a manufacturing plant that's drawing a massive amount of electricity. Then there's my favorite, signals that run to a structure and disappear underneath it without giving you a hint of what it is you are actually marking because you know it can't be the Secondary going to the bank of meters about 50 ft away.
Yes, these are some of the reasons I love this industry - you can learn something -or not-everytime you pull up on a jobsite, that is if you last long enough!

The long and short of it is this.

Oh, and get your instruments calibrated......it makes a difference.

**sundropmaster** · March 7th, 2011, 10:05 PM

Originally Posted by ifinditunderground

The long and short of it is this.

Oh, and get your instruments calibrated......it makes a difference.

Mine gets calibrated twice a year, also been checked with another RD4000 and 8000 and get the same results. On the last project I was on I noticed my signal was good for little bit then it would go haywire, then back to normal. I heard a sound from the transformer that sounded like electricity arcing, during that time frame of the sound, which lasted 5 minutes and sometimes longer, the signal was haywire, then after that stopped the signal was good. Then i heard it down the street at a power meter at the house. Pretty much down that whole street i had problems. Called the power company, all they could tell me that it might be a bad connection. And then it dawned on me that I've come across this in the past. Whatever it going on is causing interference in signal. Its not electrical dog fence close by either.

**Redd Marx** · March 8th, 2011, 01:39 AM

An "energized line" does not necessarily radiate ANY 60-cycle energy unless there is a load on the line. For example, a street light feed will only locate on 60hz when its on (illuminated). The feed to the SL is ALWAYS energized (120v) but it is not pulling any amps because it is switched off at the photo-eye. When it gets dark outside and the photo-eye flips ON, then you have a 60hz current on the line (btw - a single SL does not pull enough juice to give much of a reading on my reciever).

RE: 3-phase power mis-locates: unbalanced loads can account for irregular EM fields along three-phase lines. That is, if one of the 3 legs is pulling more amps than the other two, or if all 3 are pulling different current values (which is almost always the case), then irregularities will exist in the EM field along the of the line. Furthermore, these irregularities are compounded by the fact that the three conductors are twisted around each other in a spiral fashion. So, when you are locating, you might get a peak that is off one way and then a few steps away it will be off the other direction. The location of the peak will change according to how the loads are balanced on the three phases. So, the line could locate in one pot one day, and then a few feet away the next day. Paint wide.

**ifinditunderground** · March 8th, 2011, 10:33 AM

Originally Posted by Redd Marx

An "energized line" does not necessarily radiate ANY 60-cycle energy unless there is a load on the line. For example, a street light feed will only locate on 60hz when its on (illuminated). The feed to the SL is ALWAYS energized (120v) but it is not pulling any amps because it is switched off at the photo-eye. When it gets dark outside and the photo-eye flips ON, then you have a 60hz current on the line (btw - a single SL does not pull enough juice to give much of a reading on my reciever).

RE: 3-phase power mis-locates: unbalanced loads can account for irregular EM fields along three-phase lines. That is, if one of the 3 legs is pulling more amps than the other two, or if all 3 are pulling different current values (which is almost always the case), then irregularities will exist in the EM field along the of the line. Furthermore, these irregularities are compounded by the fact that the three conductors are twisted around each other in a spiral fashion. So, when you are locating, you might get a peak that is off one way and then a few steps away it will be off the other direction. The location of the peak will change according to how the loads are balanced on the three phases. So, the line could locate in one pot one day, and then a few feet away the next day. Paint wide.

I knew eventually somebody would pop on with a better explanation.