Two White Wires in a Light Box, Which One is Hot?

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[@bengoolie5197]

Bill, I would rather watch videos of you doing electrical work than watch an NBA Championship game, and that is no baloney! Excellent Job!

[@SparkyChannel]

Thanks so much Ben! ⚡

[@samsen3965]

LOL

[@auletjohnast03638]

Yup, don't watch the nba where they constantly kneel for the national anthem and old glory.

[@zcpoling]

Thanks for the awesome tips, Bill! I've been able to fix a few random electrical issues in my house with your easy to follow instructions, but knowing the 'why' is always a nice added bonus.

[@SparkyChannel]

Thanks Zack!

[@Guardducks]

I love those lever nuts, so much better than the stab type connectors.

[@SparkyChannel]

I agree! ⚡

[@KameraShy]

Especially for joining solid and stranded.

[@SparkyChannel]

@@KameraShy Yes, and for anywhere there might be vibration. They are superior for anti-vibration.

[@douglasfahlbusch7092]

where do I buy these in the US? not Amazon.

[@tommycho9068]

Great diagnostic test. Thank you.

[@SparkyChannel]

Thanks Tommy!

[@PoppyPerfect]

Helped a lot Bill! Thanks!

[@SparkyChannel]

Excellent! ⚡

[@pointmass]

You do such a great job with these videos.....thanks so much!!!!!!!

[@SparkyChannel]

You are so welcome!

[@Mytube5202]

AC does not have a polarity per se like DC does, the difference between hot and neutral is that neutral bus is bonded to ground in the circuit breaker panel. The light bulb doesn’t care about which wire is hot or neutral. The hazard is if the hot wire is connected to the white wire on the light fixture you could get a shock if you touch the exposed threaded contact on the bulb and ground at the same time like when changing the bulb. This is also why the line cord plug on table lamps should also be “polarized” with the narrow blade on the plug being hot and connected to the contact at the base of the socket and not to the threaded contact.

[@SparkyChannel]

Perfect explanation, thanks David!

[@gregfisher216]

Great video Bill ,I love the Wago lever nuts ! One tip ,when installing the Wago lever nuts ,I always put black electricians tape over the nut as the lever can open when putting the wires in the box. I also love the Voltage claw for pushing the wires back in the box!

[@SparkyChannel]

Both excellent products!

[@stephaniebannister7222]

I had similar confusion with multiple wires under a fluorescent fixture. There were 2 black and a white tied off doing nothing, I thought. I wish I knew about those wago’s then. I got the new light up, and working but now it won’t turn off! I’m testing and finding some WAGO’s ASAP!

[@cf-bloom3112]

My house framing/ wood seems to have voltage reading from a non contact tester..I think there are problems!.......?please help if u can..

[@jeremyandmarissa]

Can you put your two leads into wirenuts the same way you insert them into the wagos to also test for voltage as well? or do you need remove the wire nuts and test it?

[@mundlkalli4396]

Thank you for the nice video ! Question .I am installing a light fixture for ceiling light. I have one ground wire from the box/fixture and one from the new light fixture. NOW WHAT ????????????? Thank you very much !!!

[@jrpritchard1622]

thanks again for a awesome video keep them rolling sparky

[@SparkyChannel]

You bet, thanks!

[@scott_meyer]

The bulb itself really doesn't care about the "polarity". It will light either way. What we get is a safety issue. Normally hot is the small button the tip of the bulb contacts, and neutral the threaded shell. If reversed the threaded shell is hot and that presents a chance for someone to come in contact with hot while changing a bulb. They really should make sure the switch is off first though.

[@Marcel_Germann]

And that's where the problem starts. That's only possible if you have a single on/off switch. If you have several switches for the same light a layperson can't figure out if it's on or off.

[@SparkyChannel]

Excellent comment Scott!

[@markchidester6239]

Must be a switch loop. I like to use red wire marker tape rather than black because it appears labeled not just taped.

[@adl6067]

Learning something new every day Thanks 👍👍

[@SparkyChannel]

Sounds good! ⚡

[@tedmcdonald3377]

Thanks Bill, Have a great weekend😎🛠️😎🛠️😎

[@SparkyChannel]

Thanks Ted! ⚡

[@barryspoon]

Thank you so much!

[@SparkyChannel]

My pleasure, thanks!

[@brucerauch8024]

Just a thought, could you have “corrected” this at the switch?

[@JUSTACOWBOY1783]

Hello Sparky from local 520! Who else loves being an electrician here?!?! And as always, thanks Sparky for the educational videos! Love your channel!

[@SparkyChannel]

Thanks, and cheers from San Diego!

[@jameskappel]

hello Sparky, for educational purposes. I have 3 questions and if you have addressed them, would you please direct me to those videos? after multiple popping (10 times) the 20-amp circuit breaker. How Many Receptacles or Outlets on one 20-amp Circuit Breaker? Should I replace the 15-amp receptacle outlet with a 20-amp receptacle outlet? And after I forget to turn off a couple appliances, should I replace the 20-amp circuit breaker? with some recent countertop cookware appliances and other electronic devices and not wanting to overload a circuit and allow for multiple different watts. Allowing for multiple devices like a toaster oven, and coffee maker, and microwave, and crockpot, and electric frying pan, and rice maker. Also, have approx.. 16 electronics turned on in the household at any given time. Hairdryer, curling iron, ironing board, exhaust fan, radio/tv Power interruption is a big issue. A result of the household is working from home.

[@normILL]

Without turning the power back on you could tell which one is hot by continuity testing the two wires to the ground wires. So long as the ground wires are real and not fed off K&T somewhere, it should tone out the neutral. :)

[@SparkyChannel]

Yes, that's true, so long as the ground wires are good ground wires.

[@Eddy63]

Good learning vid ... Thx ...

[@SparkyChannel]

Thanks Eddy! ⚡

[@konstantinusstoyanov9749]

Thank you, great video

[@SparkyChannel]

My pleasure!

[@richardschneider9837]

Nice, hadn't seen the Ideal tap and die bits before....sometime could you do a code review and explanation video of multi-wire branch circuits. Have a commercial building where many of the lighting circuits are MWBC with the shared neutrals, but they didn't put handle ties on the breakers (at least they are adjacent spaces in the panel). I'm not clear though whether handle ties meet the intent of the code for MWBCs or if those circuits should be on a common trip breaker (such as a 2 pole for single phase, 2 circuit shared neutral or 3 pole for 3-phase panels with 3 circuits on a shared neutral, etc....or if that causes more confusion at the panel..)

[@SparkyChannel]

Hi Richard! It's so interesting how different people pick up on different things e.g. Ideal tap and die bits. The set is pricey but very high quality. I love the little case that keeps them organized too. Yes, I would love to make a video on multi-wire branch circuits. However, I am knee deep in a tough house renovation at the moment. It's been a battle, the house and property were really trashed. I can see the finish line though!

[@farmerdave7965]

I'm obsessed with good grounding.

[@SparkyChannel]

That's good!

[@Landesign58]

Hey Bill, You did a review of ideal blue silicone bands for replacing electrical tape around devices, when will you make a video showing us you using the bands as part of your work?

[@Landesign58]

I purchased a tub of these bands from Amazon for $40. These bands work great, there is no residual adhesive on the devices and the work looks so much more professional.

[@KandMAdventures804]

Great job Sparky!

[@SparkyChannel]

Thanks Keith!

[@BlackAdam2784]

Great vid ! 👍

[@SparkyChannel]

Thanks so much!

[@spiritofeverlastingendurance]

What if both white whites are hot at lower frequency from the other?

[@samsen3965]

Good your wires are at least colored. My ole house has wires that have dirty cloth covering and no plastic!

[@SparkyChannel]

I'm familiar with the situation. Best wishes!

[@randyjohnson4153]

What type of tester were you using to find out which wire was hot I noticed you didn't have to touch two wires you only touched one wire at a time and the light stays solid with hot and blinked with neutral?

[@jasonpunchedit2364]

Non contact voltage tester

[@yroncekenold878]

Good job

[@elc2k385]

Thank you, Bill

[@SparkyChannel]

My pleasure!

[@robertlee3224]

Hey Bill i have a question, would you prefer an electronic wiggy or a manual wiggy? such as a KNOPP tester, Im a firm believer in in the old school way of testing with a solenoid tester I feel that its safer and much more reliable

[@SparkyChannel]

I'm an old school manual wiggy guy. :)

[@catirerubio]

Basic electricity is confusing to me. So, with that, if the mounting box is just nailed to a wood beam or stud, how does threading a ground wire to the metal box "grounding "it? Wood is an insulator. Explanations are welcomed.

[@lonedesertfox]

Since he attached the grounding screw and wire to the box and connected the grounding wires with the wago from the romex it creates a grounded bond.

[@1965JB]

I’m in Chicago and I’ve never seen those connectors. Is that a Code thing?

[@SparkyChannel]

They do meet code.

[@febobartoli]

Bill, I’ve got two white wires going to the light switches at the top and bottom of the stairs. When one light switch is turned off, the other one won’t work. Can you explain how to figure out which wires to change?

[@SparkyChannel]

Absolutely. I just repaired that very problem in a video: How to Fix a 3-Way Switch System on a 1957 House: House Renovation Time!: kzbin.info/www/bejne/jqjceZSGfK2obNU

[@normalizedaudio2481]

I got to deal with a few of these. It is on my to do list.

[@SparkyChannel]

Excellent! ⚡

[@corygillyard1455]

Looks like old style wiring technique used back in the days when my grandfather wired his lights up. I'm willing to bet the 2 black wires were wired together being the neutral side of the circuit and the 2 whites acting as the hot. I could be wrong.

[@SparkyChannel]

Thanks Cory!

[@kenbrown2808]

to reduce the amount of walking, on a properly grounded system, if you separate the conductors, the neutral on the line cable will have continuity to ground whether the breaker is on or off. if more than one white wire has continuity to ground, you know there is a miswire somewhere. and I would have reconnected that box so it was up to current code - a white wire may be repurposed as hot, in a switch loop, but it may never be switched. so the white to the switch should have been made hot, and the black connected to the fixture. at that point, it's just one more connection to change, so no reason not to do it. addendum: neutral-ground continuity is also useful for finding the line side when installing a GFCI.

[@MarcoPolo-jg1em]

😱 you're a genious!

[@SparkyChannel]

Excellent, thanks!

[@kenbrown2808]

@@MarcoPolo-jg1em nah, just done this a time or two.

[@jamess1787]

Could you not check for continuity of neutral to ground? This would show which one is neutral, leaving hot? Or maybe not?

[@esl4058]

That would work but only assuming the grounding system is secure. With a sloppy box like that with two whites and no proper bonding/grounding, who knows what else could be going on haha

[@SparkyChannel]

@@esl4058 Perfect answer. So the answer is yes, but I prefer to use methods that are sure-fire under bad wiring conditions.

[@garydudgeon]

Good video Sparky.

[@SparkyChannel]

Thanks Gary!

[@Around_The_Home]

Question. I see there are two black wires twisted together in the box. What are they being used for?

[@MarcoPolo-jg1em]

Constant power going to the switch box

[@SparkyChannel]

@@MarcoPolo-jg1em Yep.

[@Around_The_Home]

@@MarcoPolo-jg1em Thanks

[@salvatoresaccoccio2379]

Quick question, why would a neutral turn hot? Anyone able to explain this one. House has recently installed solar panels! Help this new homeowner please.

[@toddknaub6816]

It's a cheap way of wiring. They'll take a 2 wire to the switch and NOT MARK the white wire from the switch as an energized conductor

[@christophereaton4694]

I just use my little liar. Um I mean my non contact voltage detector. Love you're posts by the way.

[@SparkyChannel]

Thanks!

[@derektorres658]

Nice video 👍

[@SparkyChannel]

Thanks Derek!

[@highqualityhomemaintenance7565]

Does the reverse polarity cause the light bulbs to burn out sooner than normal. I heard someone tell me that the bulbs in their ceiling fan keep burning out, so they are going to replace the fan. Asking for a friend. Lol

[@Marcel_Germann]

Safety issue on systems like Edison sockets. There the base contact should be connected to the line/hot and the outer threads (which are touchable, especially when changing the bulb) should be connected to the neutral. Otherwise when unscrewing the bulb the thread of the bulb is exposed and could be live at mains voltage and can be touched very easily.

[@kenbrown2808]

on an AC system, the filament doesn't care about polarity - but as marcel said, reverse polarity makes accidental contact easier. if it's a light in or on a fan, there can be vibration that makes incandescent bulbs fail prematurely. If your friend wants to use incandescents for some reason, they should spend the extra to get lamps that are intended for use in fans, because they are designed to be more vibration resistant.

[@SparkyChannel]

Some LED drivers will either not work or burn out sooner with polarity reversed. So that is another reason to make sure that polarity is correct when installing electrical devices.

[@highqualityhomemaintenance7565]

@@kenbrown2808 Thanks Ken. She never mentioned the style of bulb, but locally incandescent bulbs are virtually impossible to find.

[@AJA48]

What if you have two black wires on a two way light switch?? Do you follow the same method in checking in checking?? Thanks AJ

[@SparkyChannel]

What country are you from?

[@AJA48]

I’m from Hawaii. My house was built in 1956.

[@SparkyChannel]

@@AJA48 Aloha! What island? We LOVE Hawaii, especially the big island. The reason I asked is that in the USA we call them 3-way switches while in some other countries they call them 2-way switches. You'll get a lot of info to answer your question here: How To Replace 3-Way Switches on a 50's-60's House and Avoid Common Mistakes: kzbin.info/www/bejne/rWXQnYWEfKmdgdE

[@AJA48]

@@SparkyChannel Honolulu

[@SparkyChannel]

@@AJA48 I love it!

[@CarlosSanchez-bg4wf]

Get your tester duh

[@jamescabaniss5857]

Man, it took me a while, but I finally figured out that my GREEN wire was the hot one, and the two white wires were my neutrals. I have no ground wire. Super confusing. I had two white wires tied together and a separate green wire coming out of my light socket. I used a multi-meter and a touchless meter to figure this out.

[@SparkyChannel]

Wow!

[@1topfueldrag]

hey, is your brother Scottie Kilmer? Cause y’all sound the same

[@SparkyChannel]

Rev up those receptacles! No relation, sorry.

[@lonedesertfox]

@@SparkyChannel Bill, that was real dadgum funny!

[@dalewise5586]

Overall you do a terrific job of explaining things and I enjoy your videos. But, in this case I take exception. The really correct way to “fix” this would have been to move the white wire (to the switch) over to the hot, identify it as such. Then pull the switch and identify the white as a hot so that the black wire returning to the light was the switch leg. Now you would have one black and one white in the wall box thus eliminating the confusion. And in the future if someone tried to use the wires at the switch to add a receptacle they would see that the white was not a neutral. Or at least they should see it as such. The correction to the grounding was spot on.

[@ryanm2084]

Which one is hot? The one that makes your tester beep... Or the one that has 120v to ground using your meter

[@lonedesertfox]

Using the non-contact voltage detector one is able to figure out which wire is hot. When you measure with the meter to the ground connecting wire you are able to figure out which wire is neutral ( which will have no voltage going through) and the hot (which will measure about 120volts) upon placing the leads on the ground and a corresponding wire.

[@oshtoolman]

Are my eyes deceiving me? Arent there two black wires connected via a twisty wire nut? I can see that at the 25 second mark/

[@SparkyChannel]

Yes, there sure are. I didn't disturb them.

[@scott_meyer]

Probably the hot that leads to the switch.

[@dannycalk8051]

Why would someone wire it in this manner ???? Why did you wire it like it was, apparently it goes to a single pole switch, so why not take the white going down to the switch, and twist it and the hot black wire and cap them off and then that leaves you a black and white for the fixture. I think that only in residential is it permitted to energize a white wire.,

[@jasonpunchedit2364]

Just faze it

[@alforliniteaching5670]

Good show.:-) :-) :-)

[@SparkyChannel]

Thanks!

[@sparkyjerred419]

Switch loops were done incorrectly alot for some reason.

[@SparkyChannel]

Prior to 2011 those were OK but the hot wire wire had to be identified.

[@sparkyjerred419]

@@SparkyChannel I don't think so as reidentification would be required along the entire length of the conductor & only the white wire wasn't allowed to be switched even in 2002. They should have tied the white in with the hots.

[@SparkyChannel]

@@sparkyjerred419 No, you only had to re-identify the wire ends. Believe me, I was an electrician during that era. That's the way we did it. :)

[@sparkyjerred419]

@@SparkyChannel I was also a master electrician at that time & the white wire was not allowed to be switched it could be reidentified & used as the feed to the switch but not as the switched conductor. If you were switching the white wire you were violating the code. It's simple to correct just take that white wire going to the switch & tie it with the hots in the fixture box & take the black from the switch & connect it to the light.

[@charlesviner1565]

👍

[@SparkyChannel]

Thanks Charles! ⚡

[@andrewstaton6077]

Just me or does he sound like Scotty Kilmer?

[@SparkyChannel]

No, I don't sound like Scotty, Scotty sounds like me! LOL!

[@andrewstaton6077]

@@SparkyChannel haha great response anyways, I enjoy watching you both so thanks!

[@dagreat8089]

None hopefully

[@SparkyChannel]

LOL, yep!

[@dan260140]

Previous guy did a poor workmanship on the wiring

[@SparkyChannel]

Yep.

[@konamanstudio2447]

👍🏻🍻🍺🐶

[@SparkyChannel]

Cheers! ⚡

[@marlonescander8359]

no need polarity for a light bulb..polarity is only for 3 phase motor or a DC volt equipment...110 volt to 220 volt is we called AC volt.it means alternating current.any way you wired an AC volt is still a complete circuit happen.even line or neutral reverse..

[@SparkyChannel]

The base contact should be connected to the line/hot and the outer threads (which are touchable, especially when changing the bulb) should be connected to the neutral. Otherwise when unscrewing the bulb the thread of the bulb is exposed and could be live at mains voltage and can be touched very easily.

[@SparkyChannel]

@@raygreeninfo Safety first, always!