I think the only reason the leads are different colors is because the unit measures DC as well as AC.

Yeah but even then it's kind of silly as the thing doesn't give a detect or otherwise give a hoot about polarity. It's just a bunch of Neon bulbs.

Thank you for your responses. It's highly appreciated.

"Nothing you do with a voltage tester and household voltages should harm
it. Your scenario makes no sense whatsoever. The tester doesn't know or
care which lead you touch first."

Then I wonder what went wrong or what I did wrong. The lead I put to hot is fried and sparks flew everywhere.

What I did:

1. Put black lead to ground (It seemed ok, I felt not even a slight current as one might feel in a touch lamp.)

2. Put red lead to hot.

It was all so fast, but I believe there was a popping sound right before the sparks flew. I immediately pulled my hands back (natural reaction) and nothing else went wrong.

Returned the Voltage Tester and bought a new one (same one because I want to understand what went wrong here).

I just want to understand what I did wrong.

I'm not familiar with your tester, but some have the ability to measure current. To do that, you would plug at least one lead (probably the red one) into a different jack, probably labeled "current" or "Amperes". If your tester was set up that way and connected the black to ground and the red to hot, then, yes, you would fry the tester and also trip the breaker. Is that what happened?

If sparks flew, something else is wrong. I suspect what you damaged is the probe itself because you somehow managed to get it across the 120V in the panel somehow.

MTVHIKE...this thing is not that sophisticated. All it has is a few neon bulbs and resistors in it.

Thanks, Ron

Thanks again!

"I'm not familiar with your tester, but some have the ability to measure current."

Yes, this measures current. I don't think I tripped the breaker, but I didn't check at the breaker box. I just checked all surrounding lights to see if they were down (which they weren't). I will specifically check at the breaker box when I get home tonight.

"If sparks flew, something else is wrong. I suspect what you damaged is
the probe itself because you somehow managed to get it across the 120V
in the panel somehow."

If the "probe" is the metal tip/lead at the end then, yes, I damaged the probe? As for damaging the probe because I somehow managed to get it across the 120V in the panel somehow. I'm not even sure what this means... electric nube, that I am.

I should clarify that this was all in a lightswitch. I'm not sure it makes a difference. I didn't think it would as long as I knew which wire was which. Everything seems connected correctly. Black wire is to hot screw. White wire is to neutral screw. Ground wire (copper) is to ground screw. All of the wires appear to be coming out of a thicker white wire.

More information (in case important): this lightswitch was damaged by a cleaning spray. I knew not to use it while still wet, but I didn't know it was damaged and went to use it some weeks later, and it broke off. As I can see, it appears to have been melted.

IF this meter also measures current, and you had it in current measuring mode, then you shorted it across 120v. And released the Magic Smoke.

The meter you linked in your first message does not measure current. It's only a voltage tester. The amount of current it passes is negligeable. There is no such thing as NEUTRAL on most light switch (fancy homeautomation things excluded). There's more to electrical wiring than color matching.

My error, I assumed since it could tell the difference between different measures of electricity, it was measuring the current.I guess it's instead measuring voltage.

I checked the breaker box, and nothing was tripped. I was perplexed about neutral being on a light switch since some vids I watched had it, and some didn't.

I know there's more to electric wiring than color matching lol. Thank you for clarifying that though.

There is a neutral on this lightswitch unless it's possible that there are 2 hots? I can clearly see the ground as it's very distinct.

Black wire is at top (right) screw.

White wire is at bottom (right) screw.

Copper is at bottom (left) screw.

All wires are wrapped clockwise as should be.

This is just a simple light switch (single pole), nothing fancy. Switch controls just one ceiling fixture.

I guess I must have created a short (as weedmeister said). I just don't (at this time) understandthe "how". I have more reading and learning to do.

Thank you again for the responses!

No, there is no neutral on a (traditional lightswitch). There is the hot (fed in from the panel) and there's a switched hot. Neither is a grounded conductor (i.e., neutral). It's a pretty common rookie mistake to connect the hot and neutral to a switch and when you turn it on BOOM the breaker trips.

Ok, so the two wires coming out of the same cable - one is a hot and one is a switched hot... and then the third is a ground? I think I get it. I just haven't seen a cable like that in any of the vids I've watched so far. It's all been: hot-neutral-ground so far.

So as long as I just connect everything identically to how it's connected now, it should be all right (I guess) since the switch was working before. That's what I was going to do anyway, but I just wanted to learn a bit as I go since I'll have much more electrical work to do as I go on in each project of my house.

Thank you very much for all of the feedback and all of the information. It does not go unappreciated.