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Thread: Buy EITHER a 12vac or 120vac LED light

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    kevreh's Avatar
    Join Date
    Jun 2007
    Annandale, VA

    Buy EITHER a 12vac or 120vac LED light

    Quote Originally Posted by Kias
    They're both perfectly safe when installed properly.

    The only difference between low and high voltage is how fast it kills you. Technically it's the current that'll do you in, but you can't have one without the other. Besides who would pay attention to a sign that said, "HIGH CURRENT!"

    Both 12v and 120v are considered low voltage. It's all relative. --I'm going edit this a bit-- In my field both of these are considered low voltage. In the housing industry, I do believe only the 12volts is low voltage. Like I said, it's all relative. ---Done with my editing---

    As an example, at work, I sometimes have to replace these tiny inverters that are used to light up these small fluorescent bulbs used to illuminate a panel. The output of these inverters is on the order of 10,000 volts, but the current is so low it doesn't do anything but 'gitchya' if ya bump into it, which I quite frequently do. I'll also tape a wire coming from it to my lab's doorknob. Teaches people real quick that I really don't want to be disturbed.

    I also use two GPU's for testing the electronic controls of such, on a daily basis. The first one outputs 28.5 volts DC. There's no 'gitchya' on this thing, no "barely a tingle". Touch it, you're dead. It's output can go to over 2000 amps before the overload circuit shuts it down.

    The other test stand is a 90 KVA unit which ouputs 115 volts AC at 400 hz. I usually get a blank look when I tell people it's 400 hz, so I tell 'em it's so it will kill you 7 times faster than a wall outlet. Anyway... This thing can put out over 200 amps. Again, touch it you're dead.

    Well... Maybe the touch it you're dead scenerio is a little harsh. More like "touch it you're dead, or if you're lucky, you'll wish you were dead." I also don't frequently bump into the output of these units, and don't hook those up to doorknobs. I also have a cool red smash button that'll shut down the machinery I use when people walk too close to me while I'm running them. Then I get to yell at em!

    While doing a klystron adjustment on a radar, back in the day, my friend got hit with 15000 volts at *-=classified=-* amps. I hit him in the head with the 10 pound tech manual I had in my hand to get him off, as his hand muscles clamped down tight and he couldn't move. It was quicker than running around to the otherside and killing the power... He lived, only because the current went in his right hand, and out the bottom of his right foot, missing his heart. He had a 2 inch crater in the bottom of his foot. (and a welt on his head) After much paperwork, and much investigation, it was found there was a microscopic crack in the insulation of the wiring causing a world-wide recall... ya think?

    Wow, I am so far off topic now.

    Ummm... ya, 12v light, 120v light, they're both safe when installed properly.
    So Kias....if your still around.... couple follow up questions.

    - So I'm going to buy EITHER a 12vac or 120vac LED light (the Intellibrite 5g made by Pentair). Both lights use about 70w. Since its the amps that kill you, technically doesn't the 12vac pull more amps? 70w/12v = 5.8a, 70w/120v= .58a)

    - The 12vac light requires a transformer, going to use this one by intermatic: Would the circuit gfci in my pool panel that powers this transformer provide adequate safety? BTW, the description for this product says "A grounded shield between the primary and secondary windings assures safe operation and the built-in circuit protection will disconnect power to the transformer in case of defect or overload. These transformers are suitable for direct connection to underwater Pool and Spa lights."
    16x32 Concrete IG, 20+ years old and going strong
    Equipment: DE Filter, Jandy Gas Heater, Solar Panels, 1hp Hayward Pump with 3/4 HP AO Smith 2 Speed Replacement Motor, Aquarite SWG
    Automation: Pentair Suntouch controller w/solar valve
    Cleaners: Polaris 280 (replaced an Aquabot)

  2. Back To Top    #2

    Join Date
    Apr 2011
    Warner Robins, GA

    Re: Are 12v lights safer than 120v?

    The amount of amperage to kill is very low 100- 200 milliamp range. Voltage is what is needed to push (voltage is force EMF ) through the resistance of you body. Both lights are safe when installed properly.

    Stop worryring about 12V or 120 v lights. As far as cost savings Higher voltage units use less current, (basic ohms law) and cost less to operate. But in this case it is negligible.

    Find the better price on the lights and go for it.
    16 x 32 Grecian Vinyl. Salt-Aqua Plus PS-4, Hayward Pro Series Sand Filter, Hayward Ecostar SP34000vsp, Gulfstream HE-125-T-A Heat/Cool heat Pump

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    JasonLion's Avatar
    Join Date
    May 2007
    Silver Spring, MD

    Re: Buy EITHER a 12vac or 120vac LED light

    Either kind of light is extremely safe.

    Nominally, a low voltage light is safer. It isn't the current through the bulb that matters, it is the current through your body. Since skin resistance remains constant, the current through your body varies with voltage (lower at lower voltages). Low voltages can't produce enough current through your body to do any harm. However in practice both kinds have proven to be extremely safe when properly installed
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

  4. Back To Top    #4

    Join Date
    May 2011
    Orange County, CA

    Re: Buy EITHER a 12vac or 120vac LED light

    Jason is quite correct, as long as the 120V lights are properly installed. This means they MUST be installed on a GFCI protected circuit, and that that GFCI module is frequently tested (e.g. once a month). There are numerous examples of people being electrocuted by improperly installed or maintained 120V pool lights. I am not aware of any examples of electrocution by an improperly installed/maintained 12V light circuit. For this to happen, there would have to be a failure in the transformer such that the 120V side would energize the 12V side, and this would have to be unprotected by a GFCI. The common thought that "current kills" may be true, but it requires voltage to deliver those amps. Resistance for a given distance from the electrical short, and poolwater ion concentration would be constant.

    Ohm's law: I=V/R

    Let's consider a value of 1000 ohms for a wet body (though this is hard to calculate because conductivity through the body also requires knowledge of the total surface area and distance from the electrical source).

    Given this, which is worse, the 120V or 12V short?

    I=120/1000 = 0.12 A = 120 mA

    I=12/1000 = 0.012 A = 12 mA

    BTW, 60 mA of AC current is sufficient to cause defibrillation of the heart, and loss of control of skeletal muscles.

    So, the 12V circuit is inherently safer, by 10 fold. I think some confusion is out there because people assume that, given the greater amperage draw of a low voltage bulb vs. a high voltage bulb of equivalent wattage, there would be greater amperage in the water. However, that current is being drawn into the lighting element with its much lower resistance, and not through the water to the body. The current in the water that would be capable of electrocution is dependent on the resistance of the path to the body.
    38K in ground pool with attached spa. Current equipment: Easytouch 8 (521150) with IC-60 SWCG with web control by Autelis, 1x Pentair IntelliFlo 011018 pump (for filter), 1x Pentair 2HP WhisperFlo pump (for waterfall), 2X Pentair IntelliBrite 5G 12V lights, Pentair MiniMax400 NG Heater, Pentair SMBW2060 DE filter. Zodiac Barracuda MX8 cleaner on dedicated cleaner line. Lighting/home automation controlled by Insteon/ISY-99i.

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