Wire tracing advice needed

nicholas bonham-carter

Following a fire in one of our apartments, the panel serving that apartment has been disconnected.
Is there a way to identify all the now dead wires (connected to that apartment) running in the attic?
Would a circuit-board signal tracer enable this?--NBC

icesailor

I can't tell you what it is. I've seen an electrician put a device on a wire at the panel and use another device like a Tick Tracer to find the wire at a different location. Also used for finding electrical boxes covered over by drywall installers.

I'm just saying so you know that there is something.

Zman

I picked up one of these a few years ago http://www.techtoolsupply.com/ProductDetails.asp?ProductCode=GRE-601K-G

It is not specific for what you are trying to do but is a very nice tool. The down side is that you would have to do it one wire at a time. The nice part is that you don't have to make contact with the wire. I have found plugs and switches buried behind drywall, 30 years later. You can verify t-stat wires without removing the t-stat. you just isolate the wire in the mech room and walk around the house until you find the one. It works well trying to find one wire within a bundle.
I have watched sparkys using those multi circuit toners. Sometimes they work well, other times they are frustrated.

Carl

Mark Eatherton

Open, Closed, Pass, Fail. You could use an ohm meter, and open all circuits where terminations are known (no wires touching), then perform an open circuit ohm test. If that passes (no closed, short circuits), then wire nut all wires on one end together, then retest, paying attention to the ohms of resistance. All resistance between wires should be the same. If not, wire may be partially burnt through.

If it passes that test, then its good to go. If it fails, time to consider replacement of the wires, If thermostat wire replacement is impossible, then consider wireless thermostat technology. Things have advanced significantly over the years. Your neighbors garage door opener will not turn your thermostat to turn on or off…

For power wires, I think the code authorities will want them replaced if they were exposed to any fire at all. To my knowledge, you are not allowed to have random junction boxes, like a place to splice new into old.

Using a tick tracer can show you where the wire is, but doesn't give you circuit integrity.

HTH

ME

Zman

I hadn't picked on the fire damage element of your post.
My experience with line voltage romex is that you really need to visually inspect it. Even it it ohms correctly the insulator can be damaged. As for junction boxes, as long as they meet code for size and accessibility, they are allowed. You just can't bury them throughout the house.

Carl

nicholas bonham-carter

There are numerouse flexible metal conduits running through the attic, now disconnected from the old electrical panel, and it would be nice to be able to identify them without having to open them up. That's why I thought some sort of signal tracer could be attached to the switch, wall plug, or light fixture, and then that signal would enable the identification of the conduit elsewhere.--NBC

SWEI

Metal conduit will blocks the signal from most wire tracers, which use inductive pickups.

icesailor

SWEI said:

Metal conduit will blocks the signal from most wire tracers, which use inductive pickups.

Does that mean that those old Sparky's I worked with, before all the cool tools the modern sparky's use today, were wrong when they used a door bell ringer and jumped the other end with wither a spliced plug or a twisted wire nut?

SWEI

Works great to identify the ends of the wire, as will just about anything.

Tracing hidden cables behind a wall takes a bit more technology. If you can isolate the shields (conduit) at both ends, you can trace on that. Sometimes toning the inner wires will radiate through a bit once that is done, but it's dicey, at least using a standard fox and hound type setup. Underground locating rigs typically operate using RF below the AM band and will do a lot more.

icesailor

Like I said, Sparky has all the cool stuff.

Where I traded, they had a Plumbing & Heating store to the right, and an electrical supply to the Left. Once a year in the Fall, the Sparky's had a big trade show outside under a tent with free food and beverages. And tables set up with all the good stuff. Plumbers get Channel Lock pliers and third world screw drivers. Sparky's get Kline pliers and screwdrivers that last forever and don't break on the first screw. And all that cool wire running and locating stuff.

I found and ordered a Phillips Head screw holding screw driver, rated at 2,000 volts that held Phillips head screws. No where else have I ever seen anything like it. Perfect for putting Phillips head screws onto wires in control boxes.

Who would have known.

Sparky's are "The Chosen Ones". The rest of us mere mortals get what's left over. If you can't go to an electrical trade show and see something useful to use in your daily life, you're not paying attention.

j a_2

IF I am correct and your trying to chaze wires, in theroy its fairly simple, as long as your understanding of proper use of a multi meter is good....That said there are to many variables possible, like junction boxes and such.....if and only if each circut was a dedicated home run then pretty much only a multi meter would be reguired....HI highly doubt that....I was in another life a commercial aircraft mechanic, for broken wires we would use t d rs time delay refractomery meters . For shorted wires we would use megger meters....but those mY not help......FYI. I wont even faly anymore.....The new utes dont have a clue.....

Jamie Hall

The fire damage bothers me. It may be possible to identify the various wired -- SWEI's idea of tracing on the conduit itself might work very well indeed. However... it the wire run has been exposed to fire, even in the conduit, I wouldn't plan on using it as the insulation may have gotten overheated and damaged. Might not even show up with a megohm test, but could lead to hidden arcing. I'd be very much inclined to pull what I could out, and rewire the whole thing.

But we're paranoid about fire around this place, so I may be exaggerating the problem.

j a_2

Yup I would have agree. Get a lic. elect.

Solid_Fuel_Man

icesailor said:

Sparky's are "The Chosen Ones". The rest of us mere mortals get what's left over. If you can't go to an electrical trade show and see something useful to use in your daily life, you're not paying attention.

Wow Ice, you said something nice.....As a licensed sparky and HVAC I'm honored.

NBC, how old is the structure your talking about? You say flexable metal conduits, if this structure was wired between 1930 and 1950 you have ungrounded BX cable, it has a steel outer jacket (check with a magnet). If it's newer that 1950 it generally would have MC (metal clad) aluminum jacket.

In either case a circuit tracer won't work very well as the outer metalic jacket hinders the radio signal. Check to see if there is a ground wire in any of the boxes.

As always on the internet PICS help!

Taylor

nicholas bonham-carter

The heat damaged conduit has been cut out. I just want to be able to match up the flexible conduits in another section of the attic with the outlets/recepticles/light fixtures in the apartment affected by the fire; without cutting into the conduits.--NBC

Zman

Zman said:

I picked up one of these a few years ago http://www.techtoolsupply.com/ProductDetails.asp?ProductCode=GRE-601K-G

It is not specific for what you are trying to do but is a very nice tool. The down side is that you would have to do it one wire at a time. The nice part is that you don't have to make contact with the wire. I have found plugs and switches buried behind drywall, 30 years later. You can verify t-stat wires without removing the t-stat. you just isolate the wire in the mech room and walk around the house until you find the one. It works well trying to find one wire within a bundle.
I have watched sparkys using those multi circuit toners. Sometimes they work well, other times they are frustrated.

Carl

This one will do what you trying to do...