Finding wiring in ceiling

[mike93lx]

What is the best way to find wiring behind a layer of 5/8 drywall?

Looking to add a layer of 1/2" or thinner to cover popcorn with asbestos in it. I'd like to ID all of the wiring before starting to screw sheets up

 

[Marctrees]

Is your purpose just not to hit anything w a screw ? or something more ?

Marc

 

[mike93lx]

Is your purpose just not to hit anything w a screw ? or something more ?

Marc

That's it.

I know the risk is minimal if I properly locate the existing strapping, just want to be really cautious

 

[kbeefy]

I'm also curious. I have a car trailer that has a short in one of the 110 circuits but I don't know where the wiring is due to paneling and a bathroom. I'd prefer not to take all the interior out to find it.

 

[mike93lx]

I have a stud finder that will allegedly ID wiring, just don't know if it is the fastest or most accurate way to do it

 

[ArmchairArchitect]

You can buy USB endoscopes/boroscopes for cheap on Amazon or ebay, for around $7. You then connect that to either your laptop or phone.

From there, slowly/carefully drill holes for the endoscope to fit through, and peek around with the endoscope (which had LED lights on the tip).

Examples:
https://www.ebay.com/sch/i.html?_fr...e)+usb&_sacat=0&LH_PrefLoc=3&LH_BIN=1&_sop=15

I have one and used it just last week to spot a wire I was trying to fish down the wall.

Aside from that, assuming your old ceiling is also drywall, try to find the locations of the existing screws and screw right in front of or behind them so that you know you're screwing into a joist.

 

[mike93lx]

You can buy USB endoscopes/boroscopes for cheap on Amazon or ebay, for around $7. You then connect that to either your laptop or phone.

From there, slowly/carefully drill holes for the endoscope to fit through, and peek around with the endoscope (which had LED lights on the tip).

Examples:
https://www.ebay.com/sch/i.html?_fr...e)+usb&_sacat=0&LH_PrefLoc=3&LH_BIN=1&_sop=15

I have one and used it just last week to spot a wire I was trying to fish down the wall.

I see where that could be useful, but not for this. It would take me a week to locate everything that way and I would have to drill a million holes

 

[Zeke]

Well, you can buy a "tone" for not all that much. But the ceiling joists are very much not likely to have any wires in the lower 3rd of the joist. I say you can use 2" screws safely. Be sure to buy large head screws going up with a 2nd layer over popcorn or you'll over-sink (overdrive) most of your first attempt in any one location. Best to use a T-brace snugged up well along each joist as you go.

 

[The Cobbler]

your wiring should be 1-1/4" minimum from edge of lumber or have protector plates over it.
I doubt you have to worry about hitting any with your screws.

 

[mike93lx]

your wiring should be 1-1/4" minimum from edge of lumber or have protector plates over it.
I doubt you have to worry about hitting any with your screws.

If only a should be was enough.

There are wires running across almost every ceiling, whether feeding outlets, switches or overhead lighting. Thanks for the insight though

 

[mike93lx]

Well, you can buy a "tone" for not all that much. But the ceiling joists are very much not likely to have any wires in the lower 3rd of the joist. I say you can use 2" screws safely. Be sure to buy large head screws going up with a 2nd layer over popcorn or you'll over-sink (overdrive) most of your first attempt in any one location. Best to use a T-brace snugged up well along each joist as you go.

Interesting on the screws. Why would I be more likely to overdrive? With those large heads, will they work in my drywall gun? Wouldn't think so

 

[Copymutt]

Metal detector to the rescue!
Jim

 

[MerlinsBeard]

What is the best way to find wiring behind a layer of 5/8 drywall?

Looking to add a layer of 1/2" or thinner to cover popcorn with asbestos in it. I'd like to ID all of the wiring before starting to screw sheets up

To find wiring under drywall, I like using my A250C stud finder with the electric setting. The way it works is that the closer you are to the wire, the less sensitive it is. Basically, you’d start far away and start scanning and it will show a wire within a 12” window or more. Then you start closer to the wire and it’ll give you a smaller window. If you start at just the right distance away, it will just light up in like a 1” window, giving you a good idea where it is. You can use painters tape strips to mark the top and bottom of the range while you narrow in on it.

The quality of the electric detector usually correlated with the cost of the stud finder. After reading reviews, I went with the one mentioned and it works good if the wiring isn’t dense.

 

[Marctrees]

If only a should be was enough.

There are wires running across almost every ceiling, whether feeding outlets, switches or overhead lighting. Thanks for the insight though

You need to think this through.

Assuming an Electrician wired it what was said about the 1 1/4 is true, and normally you would never in a ceiling have only 1 1/4, but even more because it would be more like in center 1/3 of joist.

And as far as running across like alll over, if it's solid joists it's like I said, if its a truss then the wires are at least 3 1/2" higher.

Lastly... running along a joist or bottom chord of truss stiill will be the 1 1/4" minimum.

If a weekend warrior hack did it, ALL bets are off.

Think it through step by step logically, or go see how homes are wired and see.

Marc

 

[Marctrees]

Bottom line - Use screws that do not go deeper into the wood than 1 1/4", and stop worrying.

Again, unless it's a home handyman redo and especially a kitchen, you'll be OK.

Marc

 

[Marctrees]

I'm also curious. I have a car trailer that has a short in one of the 110 circuits but I don't know where the wiring is due to paneling and a bathroom. I'd prefer not to take all the interior out to find it.

Did you already first check inside ALL the boxes on this faulted ckt ?

How many boxes are on this ckt ?

If more than one or two rationalize the "midpoint" of the string and split the ckt there, then you will see which half the fault is in.

If still aproblem, next step would be looking if anything was done inside or outside where wiring was within that area.

All it takes is ONE misplaced or too long screw or nail.

In a trailer situation (thin walls) there ARE beeper type tools that would trace the wiring.

Ask an Electrician buddy... the good tracer tools are NOT cheap, AND they require some experience to use.

Marc

 

[Zeke]

Interesting on the screws. Why would I be more likely to overdrive? With those large heads, will they work in my drywall gun? Wouldn't think so

Because you're coing up against a soft surface and it won't compress as fast as your screw goes in. But do it your way. Sorry I offered advice. I'm only a 50 year verteran of home improvment and rood adds. I was skinning ceilings before you were born. In those days we bought 2" drywall nails with a 3/8ths cupped head and drove them in carefully. We still had a few pull throughs as the drywall sprung back which it DOES.

 

[Marctrees]

Zeke - I'm w you and like how you explained full support, etc., but still dunno about how the screws will work w a drywall gun...I have virtually no exp w drywall guns.

Marc

 

[mike93lx]

Because you're coing up against a soft surface and it won't compress as fast as your screw goes in. But do it your way. Sorry I offered advice. I'm only a 50 year verteran of home improvment and rood adds. I was skinning ceilings before you were born. In those days we bought 2" drywall nails with a 3/8ths cupped head and drove them in carefully. We still had a few pull throughs as the drywall sprung back which it DOES.

Zeke, I asked a follow up question to your post, nothing more. Not sure why you have a hair across your *** on this one

 

[Marctrees]

Group elbow bump time !!!!

Cut some slack, many of us have Cabin Fever.



Marc

 

[MerlinsBeard]

If only a should be was enough.

There are wires running across almost every ceiling, whether feeding outlets, switches or overhead lighting. Thanks for the insight though

I still have some open joists in the basement. They gave me 2” vertical space. If a licensed electrician did the work and it was inspected, you should be ok.