Reddit mentions: The best capacitance & resistance meters

Not worth $60 IMO. I have one of these guys and highly recommend it -
https://www.amazon.com/Mastech-MS8268-MS8261-Digital-Multimeter/dp/B000JQ4O2U/ref=sr_1_1?ie=UTF8&qid=1474646922&sr=8-1&keywords=mastech+8268

Looking through the reviews it seems like they send out the occasional lemon unit, but I've had mine for 3 years now on the same battery and it's awesome, especially for a $25 multimeter. I've tested it alongside a friend's $400 Fluke meter and it's very accurate. It also includes an attachment for reading transistor gains, which is especially helpful if you get into using germanium transistors. It's rated for 1000VDC so I use it when working on tube amps as well.

If you get into building pedals these are also worth picking up -
https://www.amazon.com/DROK-Multifunction-Transistor-Resistance-Inductance/dp/B00NKY3M1W/ref=sr_1_13?ie=UTF8&qid=1474647579&sr=8-13

It will measure inductance & and it's invaluable for getting quick gains and pinouts for transistors. It's not a substitute for a meter but it makes stuff like identifying a mystery transistor or matching FETs a breeze.

I keep a small bag in my main bag that I can clip to my belt. I mostly use it when I know I'm going to be working in a panel for a while but in general this covers 75% of my needs. Here's the bag.

Here is what I keep in it.

Wire Stripper / Needle Nose I haven't had these for too long but I really like them.

Small meter I like this one for a lot of reasons. One is that will fit in the bag and is good enough to use under 480 in my opinion.

Voltage Detector The meter has non-contact voltage detection, but I like this one more.

Crescent Wrench I like this one because it also has the monkey wrench on it so it's good for tightening air lines from time to time. Though in reality I don't use that feature much.

A couple larger screwdrivers #2 phillips and a flat head big enough to open panels easily.

Controls Screwdriver For terminals and such. I sometimes use the ones with the rotating end.

Flashlight These are not the best, but they're cheap and work as a penlight and they can do area illumination with a magnetic base.

I have seconds (and in the case of the meter and flashlights - a higher quality version) of all these in my main bag, but I mostly use this little pouch.

> Thanks so much, this looks awesome. However it also is above my head (certainly not my dad's though I'm sure). Just curious what exactly does it do aside from test transistors (seems like with software updates new functionality is being added?
>

It tests transistors, diodes, resistors, inductors, capacitors (gives things like ESR which is essential for testing capacitor health), zeners, mosfets, triacs, SCRs, etc. It also gives a square wave out and freq generator and I think one or two other functions that I forget.

The ones without the case are better because they have open pads for testing SMD components.

If he wouldn't mind a kit, I would order something like this:
https://www.amazon.com/SainSmart-Multifunctional-Transistor-Capacitance-Frequency/dp/B01L911IHC/ref=sr_1_5?s=industrial&ie=UTF8&qid=1474162673&sr=1-5&keywords=GM328+tester

For some this is a downside to a kit is he builds it himself. For me though, that is a fun upside. You know your dad well enough to know if this is good or bad.

The reason I suggest this one is that it is WAY better than any of the preassembled ones that I could find on Amazon. It has the rotary encoder to step through the menus in the newer version, it also has the nice layout for the SMD testing. eBay is tough because most of the ones on eBay ship from China and will take a month to get here.

I have a a backpack for LD (various MIDI interfaces, USB-DMX dongle, laptops, AA Maglite) or a Bum bag for more hands-on electrics (where I say Knippex, Lindstrom, Fluke. And Maglite.). And a toolbox with the all important hammer (nicknamed "sweetness"), big-ass wrenches and so on.

I try not to forget this, ever.

Also a Wera of sort, but damn this one is elegant, I wasn't aware of it.

That thingy when used responsibly is a huge help, but do NOT use it as a safety controller.

Speaking of which, I tend to get people mad by insisting on using this before starting actual work. 400mA diff NOT working anyone? It happens.

Looking at how things are organised here, I couldn't get it in one bag; long jobs end up filling my car actually: Gels, and spares, and backups, and adapters, and an actual toolbox... And the cordless drill... when I do festivals or street theatre or such, my car end up the Tool-chest, you can't possibly carry it all while on the move, but you can organise your trunk so that everything comes easily at hand.

oh my goodness!!! what a great little gadget. I had no idea something like this even exists. I checked Amazon Canada but there are so many of these, and the instruction videos shows them sticking it into the hole of the wall plug. Yeah of course it has electricity inside. Will it work on any surface like a lets say a metal countertop that is "live" for whatever reasons???

I am going to buy the one a little expensive because it seems to be a reliable brand as per the reviews. Please let me know what you think and tell me if it will work on any conducting surfaces??

https://www.amazon.ca/Fluke-1AC-A1-II-Volt-Alert-Non-Contact-Voltage/dp/B000EJ332O/ref=sr_1_5?s=hi&ie=UTF8&qid=1518252273&sr=1-5&keywords=non+contact+voltage+tester

How about that one please??

Wind your own inductors. It's easy, the only "frightening" part is wondering what inductance value you got. Luckily an old bastard named Wheeler figured that out last century, and many websites will tell you about it when you google for Wheeler Inductance Formula. Toss in the extra search word Calculator and providence will hand you several web pages that even do the math so you don't have to.

Then wind your inductor. Connect it to your transmitter and turn on the receiver, tuned to the middle of the frequency band you're aiming for. Gently lengthen and/or compress the coil windings until the receiver picks up the transmitter. Voila you have "tuned" the inductor. Now drizzle a bunch of hot glue on the coil to keep it that exact size and shape forever.

After you succeed at winding your own inductor, if you decide later that radio frequency gizmos are going to be an important piece of your electronics work, spend a little money and get inductance+capacitance meter. One that will measure 0.1 microhenries. DMMs with an inductance scale typically don't go below 1 millihenry. RF circuits use microhenries and nanohenries -- DMM ain't no good fer that.

(this one) looks cheezy but works well.

(this other one) is nicer and costs slightly more.

If you search eBay you will find lots of "LCR meter" electronic kits, that you assemble yourself, at very low prices. Check their ranges and make sure to get one that will measure down to 20 picofarads and 50 nanohenries. Or lower.

http://www.amazon.com/Fluke-1AC-A1-II-VoltAlert-Non-Contact-Voltage/dp/B000EJ332O/

This is a higher quality one and it's still pretty affordable, these would indeed be pretty helpful. Sure, hidden cameras are inherently hidden but they require some basic stuff (Power, a point of view) and based on that you can surmise where they would be should they exist.

Someone who wants to creep you would want to get you naked so bathrooms and bedrooms, aimed at toilet/shower and bed/closet areas, from there you go for POV, where could a camera be that faces these areas. There are ultra small wifi cameras but most people would go with the easiest possible installation (i.e. wired to existing power sources and so on) so it's not as hard as it sounds.

Get yourself one of these, cheap but effective:
http://www.amazon.com/Honeytek-A6013L-Capacitor-Tester/dp/B0036FQ3FW

It won't tell you ESR though. For best performance, you should change all the electrolytics in the amp. Don't re-cap the AM or FM sections! Without proper equipment and expertise, you won't be able to get the radio aligned again.

As /u/pigpen said, do not count on visual inspection. Caps often fail without any change in appearance.

audiokarma.org is the place to go if you need help.

Replacing them is extremely simple. It's just a matter of turning off the power at the electrical panel, unscrewing the plate and switch/outlet, disconnecting the wires from the old switch/outlet, and reconnecting them to the new one. Three way switches just have one extra wire. This video gives a good overview of the process.

The only tool you might want to grab is a non-contact voltage tester to make sure the power is definitely turned off before you start handling the wires. A regular DMM would work as well if you already own one.

If you’re looking for a non contact voltage tester ( tick tracer) my personal favorite is the fluke.

Fluke 1AC-A1-II VoltAlert Non-Contact Voltage Tester https://www.amazon.com/dp/B000EJ332O/ref=cm_sw_r_cp_api_i_PMRkDb24ADV56

If you’re looking for a wiggy to check actual voltage I would recommend buying a volt meter. I currently use this one and love it.

Fluke T5600 Electrical Voltage, Continuity and Current Tester https://www.amazon.com/dp/B0006Z3GZU/ref=cm_sw_r_cp_api_i_rPRkDbNV768AZ

Heres a [link](https://www.amazon.com/gp/product/B00GYSFOM6/ref=as_li_ss_tl?ie=UTF8&psc=1&linkCode=sl1&tag=tampfreepcpin-20&linkId=04dc9e0d8b201e73fcd0a87f113ab198) to the meter in question, and [here](https://www.youtube.com/watch?v=qDABYKoVO4Q) is a review/demonstration from a popular YouTube TV repair channel.

​

If you want something a little nicer, there is also [this one](https://www.amazon.com/dp/B005NIBEYU/?coliid=IBGOVNQDXLV6V&colid=35YG4HLU6VOCB&psc=0&ref_=lv_ov_lig_dp_it) for $130, it has the ability to discharge capacitors as well which is nice, and something you should do to prevent damaging your meter.

I googled and found...this guy and also this guy and a few more in related products. Yes, I know you can also use a multimeter as well this just looked like another fun gadget.

I would recommend getting one of these non-contact voltage testers (or similar). They work great and you don't need to have physical contact like a multi-meter. That's very handy if the wires are not exposed.

Mine saved my bacon when I was replacing the outlet in the bathroom. I shut off the breaker for the bathroom, but still tested the outlet to be sure. To my surprise, it was still live (must be a different circuit to handle hair dryers).

For a pretty comprehensive list, check out this, but here's my list of basic, around the house tools that you should have that aren't on your list above. I didn't include garden tools.

• Screwdrivers
  
  
• Utility knife
  
  
• Tape measure
  
  
• Stud finder
  
  
• Level. Use long ones for items that are long or tall, use small ones for smaller objects
  
  
• Drill/driver, preferably cordless
  
  
• Drill bits
  
  
• Circular Saw
  
  
• Channel lock pliers
  
  
• Vise-grip type pliers
  
  
• Plumbing equipment, especially teflon tape
  
  
• Crescent wrenches
  
  
• Socket set
  
  
• Five-in-one painting tool
  
  
• Putty knife
  
  
• Circuit tester. There are a couple of options. You can get simple ones that are just a probe and probe with a light that you stick into outlets, but I recommend something like this. You can get fancier with a volt meter, but for the most part a simple one will do.
  
  
  Any other tools/equipment can be purchased/borrowed/rented on a case by case basis.
  

In addition to a multimeter, get a parts tester. These things used to be insanely rare and expensive. But a few years ago, an opensource project jump started the development. And suddenly, there are tons of dirt cheap Chinese knock offs, that have added various nice little details.

Basic models cost less than $20 and are worth every cent. More expensive models mostly do the same thing but have a nicer case and some easier options to connect the part that is being tested. But fundamentally, they are all the same design.

For 80% of hardware work you just need a good, solid multi-tipped magnetic screwdriver and a pez dispenser full of excedrin.

Toss in a power supply tester like a Dr. Power II and you have nearly all hardware tools you need.

Just be aware that many software tools on Hirens are only licensed for personal use, using them for professional use would be a violation of license agreement.

If you're going to be checking networks, you're going to want a good fluke toner, and a fluke voltage tester so you don't kill yourself

You're also going to want a cat5 crimper that won't break

If you're troubleshooting big networks then pick up a fluke microscanner II, but only if it will save you several thousand bucks in effort.

ESR Meter.

It basically tells you if the caps are OK (this is highly simplified). I would recommend anyone repairing old gear get one. It can save you a ton of cash since many people just recap wholesale without checking when many times it is not necessary.

The Fluke 15B+'s finest resolution is 10pF. Which means that you might not be able to tell the difference between a 6pF and a 14pF capacitor. The only time I've see this as an issue is when dealing with crystal oscillator circuits, but I'm sure there are other things. If that's good enough for you, you should get it.

I've never heard a single bad word about Fluke meters.

As for links, here's one. This capacitance meter claims accuracy of 1pF, +/- .5% in the 200pF range. I've never used it, so I can't vouch for it, but it's just one of many, and this one is only $17.

Non-contact voltage tester is what I'd use. I linked a Fluke, but you should be able to pick up something comparable for around the house usage for around $20.

I'd bet it's 120v, and if a doorbell doesn't sound inside the house when you press the button, it's probably disconnected.

If not, there's a wire shoved in the walls or ceiling somewhere that's going hot every time you press the button.

Good luck.

For non contact testers fluke makes one of the best ones.
http://www.amazon.com/Fluke-1AC-A1-II-VoltAlert-Non-Contact-Voltage/dp/B000EJ332O

This one will let you isolate the exact wire in the panel/box that is on, versus other testers that are so sensitive it will tic on wires that are merely around other wires that are hot.

In any case all electricians need to have a non contact tester in their bag, it helps keep everyone alive.

I also purchased a DE-5000 on June 24th, 2017. I've used it for field repair of capacitors on SMPS and it works wonderfully. It has features found in units 5 times it's cost. The original design was by IET but I believe the OEM must be selling it directly now. The price for the IET branded unit was much higher. Dave Jones did a teardown of it but my favorite review is by TRX Bench. Test Signal is 0.63VAC RMS when I measured it. Here's the Manual.

Many multimeter's will also measure some range of capacitance, but it depends on your needs. I give another vote for the Mega 328 based multifunction testers. My personal device is a "Drokking" Chinese clone, which added a color screen. There are many other versions available.

https://www.amazon.com/DROK-Multifunction-Transistor-Automatic-Identified/dp/B01MS1FOYM/ref=sr_1_1?ie=UTF8&qid=1523595943&sr=8-1&keywords=drok+transistor+tester

These things are awesome- fairly accurate, and a real time saver if you're working with discrete components often.

I've got one of these on my Amazon list.

Good enough for day-to-day tinkering / identifying those random parts you got in a box of junk years ago. That one's packaged better than others I've seen on ebay/Amazon/etc.

It's probably fine but considering it's electricity I'd stick with the tried and true. Any electrician in the US will tell you Fluke is the gold standard.

Edit- apparently "less than 20 dollars" is no longer true.

https://www.amazon.com/Fluke-1LAC-Voltage-Detector-1000V/dp/B000EJ332O/ref=sr_1_9?keywords=klein%2Bnon%2Bcontact&qid=1566832341&s=gateway&sr=8-9&th=1

I should also mention I like this one best because the Klein ones can be sensitive to bumping and give off false positives: Fluke 1AC-A1-II VoltAlert Non-Contact Voltage Tester https://www.amazon.com/dp/B000EJ332O/ref=cm_sw_r_cp_apa_i_5HP2Db6VTSXP3

I'll second the call from /u/Cheech47 that you should get a multi-meter. I'll go even further and say you should also get a non-contact voltage tester. The one linked is my preference, but just don't pick up whatever cheapy they have at Home Depot or Lowes. You want one that will work in a marginally crowded box without just going off because *something* in there is hot. =)

> I'd at least take it apart and use a multi-meter to see if the wires are hot.

I would NOT recommend using a multi-meter to see if the wires are hot. Get yourself one of these things. I consider them an absolute essential for any homeowner or DIY'er. It's a very easy, and relatively safe, way to test for a live cable.

Without knowing what he's already got it's hard to say. He's probably already got all the basics. I'm just assuming he's already got boardsaws, tape measures, screwdriver sets, plier sets and so forth.

I'll list off a couple of things I would rather not live without:

[Irwin wire strippers] (http://www.amazon.com/Irwin-Industrial-Tools-2078300-Self-Adjusting/dp/B000OQ21CA) These are totally awesome.

[Non contact voltage detector] (http://www.amazon.com/Fluke-1AC-A1-II-VoltAlert-Non-Contact-Voltage/dp/B000EJ332O/ref=sr_1_3?s=hi&ie=UTF8&qid=1449993757&sr=1-3&keywords=Non+contact+voltage+detector)

Stubby ratchet screwdriver

These are great too.

yep cant tell a cap is good always by looking, usually need an ESR meter

for cheap component tester I use this, Mega328

Well, it was likely an issue with the power circuitry. At least, that is most likely the culprit. The filtering caps in there get hammered a good bit. You will need to get a cap tester. Another not so technical test is to see if the tops of any of your caps are bulging. This typically means they are failing. Once you find the bad one(s) write down the voltage and capacitance then either order online (I use digikey.com a lot) or go to radio shack or something.

Have you ever soldered before? If not, you are going to need a decent soldering iron, some solder, and some desoldering wick. The wick will remove the solder holding in the current caps. This allows them to be freed. Before removing make note which hole the negative lead is in (electrolytic caps are polarized) so if you reverse it they will go pop when you turn it back on. Once your new caps are properly positioned go ahead and solder them in. Then sit back and pat yourself on the back for saving a shitload of money.

Sounds complicated, but it is actually pretty simple to do.

https://www.amazon.com/Fluke-Voltage-Detector-1000V-AC/dp/B00ATGPRRQ

$26 bucks at Amazon, cheaper at your local hardware store.

You can get a free multi meter at Harbor Freight with purchase.

I'm guessing that the issue is a lack of shielding/balancing in the wiring to those speakers either from a floating ground or from the type of wire being used.

A lot of PA installations are done with just a single pair solid or braided core wire that has literally NO shielding.

Properly done, you would have a grounded metal shield on the wiring (like with RG-6) that connects/grounds the shielding on all of the speakers and the amp/source/power brick.

Additionally, the speakers/power block/source and any other equipment on the circuit should be isolated from any ground other than the signal lines, or on a shared ground with the EXACT same ground potential at all points.

(unless your electrician has a 100ft+ line on a dedicated ground test meter, he probably hasn't tested that there isn't a ground difference between different locations in the building)

Additionally, for longer runs, it's pretty vital to use a balanced signal (like XLR).

Hmm, that link should take you directly to a voltage tester. Here's another one off Amazon that appears to be getting good reviews: http://www.amazon.com/Fluke-1AC-A1-II-Volt-Alert-Non-Contact-Voltage/dp/B000EJ332O/ref=sr_1_1?ie=UTF8&qid=1343538975&sr=8-1&keywords=voltage+tester

It looks like you're trying to format a word into a link. Try this instead:

> [this](https://www.amazon.com/dp/B000EJ332O)

Result: this

Got it fixed? Downvote to delete.

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I've heard good things about this: http://www.amazon.com/Labs-DE-5000-Meter-Replaced-DE-6000/dp/B005EMT8PC

One of these days I'll find one that isn't double the price in Canada...

not really, it's almost the price of a DER EE de 5000, which is an actual good lcr meter in addition to just being able to test ESR.

https://www.amazon.com/5000-Handheld-LCR-Meter-accessories/dp/B00S298KJO/ref=sr_1_1?keywords=DER+EE+5000&qid=1554329265&s=gateway&sr=8-1-spell

I’d want to determine which of those wires is hot and which is neutral. Like with a Non-contact voltage sensor.

Here are two tools that help:

Tells you if an outlit or wire is hot before you touch it:
http://www.amazon.com/Fluke-1AC-A1-II-Volt-Alert-Non-Contact-Voltage/dp/B000EJ332O

Allows you to find the circuit for an unlabeled outlet:
http://www.amazon.com/Sperry-CS550A-Circuit-Breaker-Finder/dp/B000ET403A

For anyone that doesn't mind spending some money on a "pro" meter, I have this one and like it: Agilent/Keysight U1733C

I see no problems with that meter for general use. I have an earlier model of that meter (Fluke 12B) that I keep on my bench at home for double checking resistor values. You might want to consider an ESR meter for checking capacitors. Here is a cheap one with good reviews: http://www.amazon.com/Honeytek-A6013L-Capacitor-Tester/dp/B0036FQ3FW

Yeah, I used one of these. Not sure how accurate they are, but you could be right about it reading another wire.

Going strong year 2.5 with this bad boy. Everyone seems to come to borrow mine when their milwaukee / klein / greenlee is being bothersome.

Edit: Mine lives on the top left shoulder strap of my vest. Never leaves that place. If mine was to break tomorrow I'd feel I got my monies worth out of it.

You can use one of these to test if the line in the wall is still live. Push it in the hole you made and it should light up. Then turn off breakers one by one until the light on the sensor turns off.

Will this work @Tufts_Student : https://www.amazon.com/gp/product/B0036FQ3FW/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

Was it this one? I was considering buying it just yesterday. Is there any documentation/firmware to be found for this kit?

> classic Fluke

You mean this one?

That Klein non contact tester is garbage, go with the tried and tested fluke

http://www.amazon.com/gp/product/B000EJ332O?ie=UTF8&camp=1789&creativeASIN=B000EJ332O&linkCode=xm2&tag=vrefid-20

http://www.amazon.com/Honeytek-A6013L-Capacitor-Tester/dp/B0036FQ3FW/ref=sr_1_2?ie=UTF8&qid=1394686851&sr=8-2&keywords=capacitance+meter

I think he means an induction meter/tester.

It's already on the way

http://www.amazon.com/Jyetech-Capacitance-Meter-DIY-KIT/dp/B00C5TRI3Q/ref=sr_1_1?ie=UTF8&qid=1404340293&sr=8-1&keywords=jye+capacitance+meter This is one I bought and built, it's 1pF to 500 uF.

He found it without a Fluke: http://www.amazon.com/Fluke-1AC-A1-II-Volt-Alert-Non-Contact-Voltage/dp/B000EJ332O/ref=pd_cp_hi_2

I have one of these in my bag to prevent just such an occurrence. You don't realize how handy they are until you've used one and lost it.

We're redoing electric in our house, and the only advice I can give is do not trust any labels unless you've tested it yourself twice. We made an updated wiring map of our house using walkie-talkies and a no-touch tester. There was no logic to the map whatsoever. Half the house turned out to be wired from one 12A breaker. One room had outlets attached to 5 different breakers. Double-taps and duct-taped wires everywhere... It's going to be a long project.

I have the same non-contact tester. It is very sensitive. I was at a friend's house helping him install a ceiling fan. We had the breaker off and used the non-contact to verify that the circuit was dead. When I got on the ladder to test in the ceiling box, the tester was going crazy. His wife had these lights hanging from the ceiling. The tester was picking up the magnetic field from them, even though I was 3 to 4 feet away from them.

This is the model I use at work I haven't had any issues with it giving false readings when it is around a lower voltage source. However, if you have enough static electricity, it will pick it up.

> I would NOT recommend using a multi-meter to see if the wires are hot.

Why not? Also, you can use https://www.amazon.com/dp/B000EJ332O as the url, you don't have to add all that extra crap to it

\> voltage detector is showing current on the parts that are not lit.

​

non-led christmas lights have a shunt that forms when the light's filament burns out, this is so if one bulb burnt out, the series continuity isn't broken and it doesn't take out the whole strand.

​

some of the shunts don't form, and that's how those lightkeeper pros are supposed to 'heal' a bad string....by making a big pulse, enough to melt and form those shunts that didn't quite make it.

​

http://www.ciphersbyritter.com/RADELECT/LITES/XMSLITES.HTM

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actually, usually that lightkeeper pro voltage detector is pretty crappy, I use this:

​

https://www.amazon.com/gp/product/B000EJ332O

Not only that, bit live cables? Ffs get one of these at least https://www.amazon.com/Fluke-Voltage-Detector-1000V-AC/dp/B00ATGPRRQ

Why the hell would you use a multimeter? You don't need to know what voltage it's at you just need to know if there is current passing through. A contact less voltage tester would do the job just fine.

Funny you should ask, just wired these up today. I killed the circuit, pulled out the boxes (leave them wired up), turned on the circuit again, turned on the light, and used a non-contact voltage tester (like this: https://www.amazon.com/gp/product/B000EJ332O/ref=od_aui_detailpages00?ie=UTF8&psc=1) to determine which box had no power out when the light is turned on. That's where the companion goes. Now kill the circuit again and follow the wiring diagrams that come with the switches. Note: after wiring it up you may have 2 extra black leads in the companion box - they should be wired together (not to the switch). Also, traveler is generally red. In this set-up the companion is just wired to the master via the red traveler wire (not to the load/light, as with standard 3-way set-ups).

Or, check the labels on the old switches (mine said "two pole" where the master goes but where the companion went it was just a standard switch).

Turn off power at the circuit box. Test that the power is out on the outlet you're going to look at by plugging in a nightlight or something - it shouldn't turn on. Open up the outlet and look at the end of the wires connected to it. If they're silver they're probably aluminum, if they're copper they're probably copper.


Quick and easy, but not foolproof, as you're only looking at the one outlet. If your house has been remodeled it could have a mix.

​

edit: btw...if you own a house or condo you should probably just buy one of these. You put it in an outlet, or touch a wire (even a lamp cord or similar) and it'll glow/beep if there's electricity to it. Something like replacing an outlet or switch with the same kind is dead simple - although if often seems there's no way all those wires will fit back in the wall, they will. This makes it easier to avoid shocking yourself.

I'll parrot my usual recommendation.

Stick it against all sides of a wire, no beep no problem.

First thing - Check the voltage range of your non-contact tester.

If the low end is less than 90v, toss that thing in the back of the toolbox. For working with house electricity, if your tester picks up voltages less than 90v you're going to run into problems with the tester picking up voltages that may or not be running through the wire you're testing. (I've had signaling on a dead wire, but the tester was picking up from another wire about a foot away.) I've picked the Fluke Volt-Alert with the 90-1000v range so that it won't pick up transient voltages.




Next - If you're testing outlets, pick up a receptacle tester. This will let you know if any problems exist. Or you can break out a Multimeter and follow these instructions.