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View Full Version : Any tricks for finding a nicked wire?


jcom
10-12-2007, 02:42 AM
I will be using our 521 to find a nicked wire that is probably nicked along with the common.

Any time saving procedures to track this problem?

John and thanks.

FIMCO-MEISTER
10-12-2007, 06:39 AM
Having the fault finder (901 921? never can remember) helps a lot but if all you have is the 521 here is how I'd do it. Hook up just to the common at the timer with the 521 well grounded. MAKE SURE YOU HAVE FRESH BATTERIES IN IT. When you turn it on watch the needle on the main box not the wand. If it jumps to 8 by the time you get to 4 on the switch you will be far from the nick. If it stays below 8 on 5 you may be fairly close to the nick. I'd then trace the common at full strength and flag the path. Then I'd turn the wand down to half strength and go back over it close to the ground very slow. Nicks tend to bleed into the soil and sometimes you can follow a nick and never get a clue as to where it is. So when you start getting different or weaker sounds on the path you want to double flag those areas for potholing and checking. Use your Station Master but don't trust it completely since I've seen the SM go right through a nick and turn a valve on. I'd have the SM on before checking the wires to see if you are past the nick. If you are lucky the 521 will suddenly weaken along the path and stay weak meaning the nick is behind you so go back and do the best you can narrowing down the changeover sound and dig CAREFULLY. If you nick it digging it up, well never mind. Be patient, slow down, get low, mark well, avoid digging until all tracking options are exhausted.

Another method but this takes practice and can work well is to trace the furthest valve after you've established a wire path. Instead of grounding the 521 to earth use the common wire as the ground. In theory the two wires being in the same ditch should nullify each other out. When you pass or get around the nick you will pick up faint sounds. This is a great method for flushing out old valves with little resistance.
Hope this makes sense. Hands on I could teach a lot better.
GOOD LUCK

CAPT Stream Rotar
10-12-2007, 06:40 AM
:takes notes:

FIMCO-MEISTER
10-12-2007, 06:50 AM
:takes notes:

Requires cool thinking and logic helps. Also helps to be a COWBOY FAN. I understand PAT fans are totally inept at 521 usage for some reason.:confused:

Squirter
10-12-2007, 07:21 AM
Requires cool thinking and logic helps. Also helps to be a COWBOY FAN. I understand PAT fans are totally inept at 521 usage for some reason.:confused:

Perhaps some video recording would be helpful to gain further insight.

Go Colts!!!!!

FIMCO-MEISTER
10-12-2007, 07:34 AM
Perhaps some video recording would be helpful to gain further insight.

Go Colts!!!!!

Either that or I can travel around the country in a RV teaching my 521 method. Turn my vacation into a tax writeoff. It is a personal method. I suspect Purp, Mike, London, Dana, Tony and many other on this site have a unique style to 521 usage. I taught Henry the nuts and bolts of using it but he has his own style now. Yesterday we were tracking a splice and Henry narrowed the area down. I yelled I'll get the fault finder. Henry quickly got his shovel and gleefully showed me he had found it before I could set the fault finder up. At times I think he has surpassed me and I HATE ADMITTING IT!:angry:

Kiril
10-12-2007, 08:19 AM
At times I think he has surpassed me and I HATE ADMITTING IT!:angry:

Be proud of that fact, it speaks to your teaching abilities. :clapping:

PurpHaze
10-12-2007, 08:25 AM
I suspect Purp, Mike, London, Dana, Tony and many other on this site have a unique style to 521 usage.

I only use the 521 for locating the wire path, valves (the solenoids and coiled wire wire scream at you) and finding out how deep the wire is buried. I then switch to the Ground Fault Locator and run it over the wire path that I've marked with paint. It's so sensitive that it finds even the smallest ones that have very little voltage loss. You can "tune down" the GFL and look only for large ground faults and work on them first.

Ground faults are a lot like leaks. You can have small leaks that don't affect anything and are just a nuisance. Large leaks can disrupt the flow of voltage and stop the valve from working. A combination of small leaks can add up and create enough voltage loss that the valve won't fire.

PurpHaze
10-12-2007, 08:29 AM
I taught Henry the nuts and bolts of using it but he has his own style now. Yesterday we were tracking a splice and Henry narrowed the area down. I yelled I'll get the fault finder. Henry quickly got his shovel and gleefully showed me he had found it before I could set the fault finder up. At times I think he has surpassed me and I HATE ADMITTING IT!:angry:

It's the best form of flattery in that you've done your job so well that Henry not only understands the basic principles he has adapted them to his own style. You should be a proud Papa. http://www.websmileys.com/sm/animal/tier46.gif

FIMCO-MEISTER
10-12-2007, 08:37 AM
It's the best form of flattery in that you've done your job so well that Henry not only understands the basic principles he has adapted them to his own style. You should be a proud Papa. http://www.websmileys.com/sm/animal/tier46.gif

Yeah as long as he doesn't rub it in. :dizzy: :hammerhead:

PurpHaze
10-12-2007, 08:45 AM
Yeah as long as he doesn't rub it in. :dizzy: :hammerhead:

But that's part of the fun and flattery. Sometimes I'll look at something and initially decide that we'll do it one way when Leo will speak up and say, "How about we try it THIS way?" I step back for a second and reply, "Good call" to which he then starts needling me that I've trained him TOO well. Fact of the matter is that there is more than one way to accomplish a job and those that can adapt and look at viable alternatives are the ones that are shedding their monkey suits.

Mike Leary
10-12-2007, 12:00 PM
But that's part of the fun and flattery. Sometimes I'll look at something and initially decide that we'll do it one way when Leo will speak up and say, "How about we try it THIS way?" I step back for a second and reply, "Good call" to which he then starts needling me that I've trained him TOO well. Fact of the matter is that there is more than one way to accomplish a job and those that can adapt and look at viable alternatives are the ones that are shedding their monkey suits.

Yep, spot on...all who have that happen should be proud when the pups
come up with a original idea thats better than the geezers.:)

londonrain
10-13-2007, 09:43 AM
Having the fault finder (901 921? never can remember) helps a lot but if all you have is the 521 here is how I'd do it. Hook up just to the common at the timer with the 521 well grounded. MAKE SURE YOU HAVE FRESH BATTERIES IN IT. When you turn it on watch the needle on the main box not the wand. If it jumps to 8 by the time you get to 4 on the switch you will be far from the nick. If it stays below 8 on 5 you may be fairly close to the nick. I'd then trace the common at full strength and flag the path. Then I'd turn the wand down to half strength and go back over it close to the ground very slow. Nicks tend to bleed into the soil and sometimes you can follow a nick and never get a clue as to where it is. So when you start getting different or weaker sounds on the path you want to double flag those areas for potholing and checking. Use your Station Master but don't trust it completely since I've seen the SM go right through a nick and turn a valve on. I'd have the SM on before checking the wires to see if you are past the nick. If you are lucky the 521 will suddenly weaken along the path and stay weak meaning the nick is behind you so go back and do the best you can narrowing down the changeover sound and dig CAREFULLY. If you nick it digging it up, well never mind. Be patient, slow down, get low, mark well, avoid digging until all tracking options are exhausted.

Another method but this takes practice and can work well is to trace the furthest valve after you've established a wire path. Instead of grounding the 521 to earth use the common wire as the ground. In theory the two wires being in the same ditch should nullify each other out. When you pass or get around the nick you will pick up faint sounds. This is a great method for flushing out old valves with little resistance.
Hope this makes sense. Hands on I could teach a lot better.
GOOD LUCK
Peter should be a teacher......I also disconnect all wires from the controller...

The 521 and ground fault will always give you strong signals at 90deg turns in the wire path.
When using the ground fault you will also get a false reading at the mid point between your hook-up point and the fault location.

The real trick in using either equipment is understanding what they are telling you.

I had a real tricky locate a couple of weeks ago with a break on a common.
The common was tucked between three pipes and the three pipes were right next to drainage tubing. The 521 traced the wires fine and passed right over the break in the common but the ground fault had trouble locating the break.
We ended up narrowing it down by using the station master and test firing the zones at a few points along the wire run.

FIMCO-MEISTER
10-13-2007, 10:40 AM
Peter should be a teacher......I also disconnect all wires from the controller...

The 521 and ground fault will always give you strong signals at 90deg turns in the wire path.
When using the ground fault you will also get a false reading at the mid point between your hook-up point and the fault location.

The real trick in using either equipment is understanding what they are telling you.

I had a real tricky locate a couple of weeks ago with a break on a common.
The common was tucked between three pipes and the three pipes were right next to drainage tubing. The 521 traced the wires fine and passed right over the break in the common but the ground fault had trouble locating the break.
We ended up narrowing it down by using the station master and test firing the zones at a few points along the wire run.

Sometimes on wiring tough ones like LR described we just narrow the area down and if we can't get to the actual nick or break we just bypass it. Purp and I disagree on this but I think it is more a contractor/ manager disagreement. As a contractor I feel that my responsibilty is to fix the problem in a long term way at the lowest cost to the customer not find the problem even though many times we do. If we have a wire broken near an oak we will often reroute everything, pipe and wire, around the tree. I had a brown jacket muti strand wiring repair a few weeks back in which the 18ga (20ga in my opinion) was breaking off in chunks when being handled. i dragged the customer outside showed him the situation told him I could get him going again today but the next time he called on wiring issues we were going to abandon his existing wire and rerun all new single strand. the problem was I was the third, fourth, who knows how many service guys had worked on this thing and we were finding lousy short term fixes everywhere.

Kiril
10-13-2007, 10:44 AM
I would agree on the long term approach. Also, if you put your wire in conduit you would eliminate many of these wiring problems.

FIMCO-MEISTER
10-13-2007, 10:52 AM
I would agree on the long term approach. Also, if you put your wire in conduit you would eliminate many of these wiring problems.

I dread the thought of a service call with wire in conduit. I doubt there are 10 of those in Dallas. The way irrigation has been taught historically here is that the wire goes in the ditch first and then the pipe to protect the wire from getting hit by shovels. I can see that a good 14ga wire in conduit would possibly never have a service call issue.

PurpHaze
10-13-2007, 11:36 AM
Purp and I disagree on this but I think it is more a contractor/ manager disagreement.

What are we disagreeing on? Do whatever has to be done. I've rerouted many wires/mains. I've even completely rewired entire athletic fields running conduit between valves when there is a continual gopher problem affecting the integrity of a system section.

The only real differences between what I do and what contractors do is (1) I work on larger pipe/systems most of the time and (2) I know that what I do today affects me and our department in the future since we're the ones that will have to go back in and rectify the situation if I succumb to a "monkey moment" (since as we all know... the vast majority of contractors' customers are not on a maintenance contract and the next guy out to fix things will most likely be a different contractor since people shop around so much). :drinkup:

Wet_Boots
10-13-2007, 01:03 PM
Ever use flexible conduit for rerouting control wires? I wonder to what extent the stuff is critter-proof.

Kiril
10-13-2007, 06:01 PM
I dread the thought of a service call with wire in conduit.

But you see, that is the whole point. You wouldn't get a service call because short of catastrophic damage to the conduit the wire should remain in pristine condition as long as the conduit is intact.

If for some reason there is a bad wire -- pull it out of the conduit to repair or pull a replacement.