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My wall has these three wires poking out of the wall right under the cabinets. Looks like ground, hot, and neutral to me.

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I would like to put in new under-cabinet lighting. I noticed that hardwired lighting is on average three times more expensive than plug-in lighting. However, both types of fixtures look the same to me. So I'd rather go for the cheaper plug-in lighting.

While studying the plug-in lighting, I only see that they have two wires. Take a look at this LED strip light, for example. It has one red and one black wire.

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Another example is this bar light. It comes with a two pronged plug. So I'm assuming that when I strip the plug, I'll see two wires inside.

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I know almost nothing about electrical, but I already see a problem. 2 and 3 do not mix. It seems like the light fixtures only have hot and neutral, but no ground wire. Am I allowed to just hook up the hot and neutral and leave the ground unpaired? Will my light explode in some thunder storm without grounding?

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    no no no no no stop. These LEDs are low-voltage. Hot, neutral, ground are not things in 12V. DO NOT APPLY LINE VOLTAGE TO THESE DEVICES. – Harper - Reinstate Monica Sep 27 '17 at 1:22
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You are conflating 12V systems with line-voltage systems

When you say "hardwired lighting", you are actually referring to line-voltage ligthing. This runs on 120V or 230V (actually, it runs on ~12V but has an onboard conversion module) and must be cabled to the high standards of the electrical code for mains wiring. This stuff can kill you; if a lamp falls off and drops into a sink of dishes you are washing, you get to see how good your safety protection is on the circuit.

When you say "plug-in lighting", you are referring to one format of low voltage lighting. This runs on 12V or 24V, and the electrical code for wiring methods is much more relaxed. This stuff cannot kill or even shock you. If it falls into a sink of dirty dishes it will probably remain lit.

Low voltage lighting is better - for safety, for ease of wiring, and for cost - not needing a high voltage conversion module in every light.

It would pay to do some more learning about these two very different technologies.

One neat thing about low-voltage is dimming works much, much better in terms of which lights they can dim, and how much they can dim. That allows you to over-lamp your installation, and back down the brightness to what is comfortable at night, while being able to pump it up for working by day.

Convert this entire system to low voltage

The problem is, the wiring methods here are a nightmare. One does not simply put mains wiring through a crevasse in the wall. It is totally unacceptable as 120/230 mains wiring and must be completely redone at considerable expense, with lots of drywall work.

On the other hand, this sort of thing is typically acceptable for 12V/24V wiring.

Plug or hardwire has no bearing on voltage

Plugs or hardwiring are a wiring method, and work on either one. That means you are free to use hard-wired wiring methods on 12V/24V stuff.

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  • I live in USA. The internet always tells me the outlets are 120V. I plugged in one of these LED strip lights into the outlet and it worked. You say this LED strip light is only 12V. So how does it get converted? Is it this rectangular box that sits between the light and the plug hat is doing the conversion? Also, if I explicitly buy one of those 3 times as expensive hardwired lights, does that usually mean it is 120V because it can be connected to those wires punching out of my wall? – JoJo Sep 27 '17 at 7:46
  • The conversion is done in the plug, which is why it's such a large "brick" shape. There should be printing on the plastic someplace making that explicit. – Matthew Gauthier Sep 28 '17 at 3:30
  • I briefly explained this in my answer below. And briefly how it works. It's why I explicitly said not to cut the cord end off. Also, think about it, as I mentioned below, if you leave the end on and install an outlet. You can unplug the lights and cord when it burns out, because eventually it will, or if you choose to upgrade, either way, it will be significantly easier and safer. Plus, as we discussed already, YOU MUST put splices in a box, and the box must be accessible. So.... Just install an outlet – noybman Sep 28 '17 at 14:56
  • @MatthewGauthier Some plug-in lights have no brick, for example this product. How do these convert the electricity from the wall? – JoJo Oct 1 '17 at 16:09
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    @JoJo you notice those are quite a bit bigger than just the lamp. The 120V to low voltage conversion is occurring inside the fixture, or possibly, these are fluorescent and are inherently high voltage. I know this world is maddening to you because there are so many products and prices and I don't think you really have mastered AC vs DC power... But having priced a lot of this stuff, you are better focusing on DC only, including ones you do wire, and broadening your product search beyond your usual. – Harper - Reinstate Monica Oct 1 '17 at 16:30
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For your safety: GFCI - Use them. Wiring Box - Use them. Electricians - use them.

No you cannot just strip the plug off.

You might know this, but if not, here's a tid-bit for you. LED's (Light Emitting Diodes) work on DC (Direct Current). While it does not have to be whats known as a full wave rectifier it does require an AC to DC conversion process.

What you have pictured includes what we call a "wall-wart" that black box right above the outlet has a "transformer" like step down circuit. Its cheap, but it does its job. It turns 120VAC into (possibly 12VDC).

So if your plan is to use a plug in light, let it help you do its thing, and use a plug.

If you want something hardwired, realize it also converts AC to DC, but probably not right in the wire :)

Point being, if you look at the expected life of a more expensive unit, it probably surpasses the cheap-o pictured.

Getting an electrician is probably advisable in this scenario as they are going to be able to give you a lot of good advice and you can participate as well in many cases.

PS: picture 1 is illegal and a fire hazard.

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  • Sorry. I bought my house like this. I ripped out the crappy broken under cabinet lighting from the old owner and saw these wires behind them. I don’t really understand why it is a fire hazard. I also see wires hanging out of the ceilings to install chandeliers. I’ve seen many YouTube videos of people hardwiring chandeliers. How is the ceiling different from the wall? Not being defensive. It’s just I have no clue because all my knowledge is pieces together by watching dozens of YouTube videos. This knowledge is not taught in schools. – JoJo Sep 27 '17 at 7:50
  • No offense read into it. Your questions are excellent both in post and follow up. This information is taught in schools, but it is speciality in nature and you never know everything. From an electrical talk electricians have journeyman programs and other on the job training that is required before they are licensed. Being licensed is a sign that the person doing the work is doing it reliably and safely (still not a guarantee but, is close). – noybman Sep 27 '17 at 15:01
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    On the topic of wall versus ceiling with wires sticking out: the important emphasis that both responses here stated is that you have to have wire connections and splices INSIDE OF ul tested electrical boxes. Wires secured within inches of the box entry, use romex "grommits/clamps" on metal boxes and they have to be accessible. It's a fire hazard because heat sparks disconnection occur and are unseen, in a wood area, with fiberglass, etc... What does sparks and heat did to wood? What if someone buried a wire nut in a wall or under a counter or behind a stove? See where I'm going with it? – noybman Sep 27 '17 at 15:13
  • Low voltage does not imply cheapo junk, much the opposite. Low voltage LED costs less because there is no need for mains conversion, and expensive certification of the mains conversion. Of course "cheapo" exists on every product, and the weak point is the mains conversion circuit, when they cut costs there they dramatically shorten life. Anyway "cheapo" DC products tend to fare better since they don't have that problem. I have one $7 strip that has burned for 5 years 24x7 with no trouble at all. – Harper - Reinstate Monica Oct 1 '17 at 17:28
  • well, you get what you pay for regardless. I wasn't advocating for the"cheapo" (I'll call it a wall-wart or not unit). I have not looked at the circuit design of what you are calling a mains conversion in comparison to ...... something else? I mean, a plug in the wall unit or a wire to the wall unit are both generating DC, they are both converting main. Full wave rectify it and call it a day. They are both converting mains – noybman Oct 1 '17 at 21:47

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