Wire gauge for under cabinet lighting.

Discussion in 'Electrical Forum discussion & Blog' started by appdude, May 3, 2014.

  1. appdude

    appdude New Member

    Messages:
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    Location:
    Ontario
    I need help on the wire gauges, I picked a 18 gauge wire but I've also heard some stuff about the voltage drops. Is it okay to run 18 gauge wire for led strip lights. The run of the wire is 11 feet.
  2. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

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    What is the supply voltage, and what is the current required (or Watts)?

    The biggest thing on voltage drop is the amount of current and the length of the wire. Then, the fixture's installation instructions. If this is line voltage, without some low voltage conversion or a transformer, you would need to keep the wire gauge adequate for the circuit breaker that supplies it. If it is being fed from a power supply, that will normally say what gauge wire to use and would be based on the voltage and current used.
  3. appdude

    appdude New Member

    Messages:
    36
    Location:
    Ontario
    The strips need 24watts and a 12v dc adapter plug.

    12v
    24watts
    2amps
  4. DonL

    DonL Jack of all trades Master of one

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    Location:
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    18 Gauge is fine.

    A inline fuse is nice also.


    Good Luck.
  5. appdude

    appdude New Member

    Messages:
    36
    Location:
    Ontario
    Last edited: May 4, 2014
  6. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
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    Location:
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    Every time you add a connector, you have an added resistance - it would probably work fine, but initially monitory things and see if the connector or wire gets hot. Some power supplies have overload protection built-into them, so while a fuse never hurts, it may or may not add much to the overall safety of the installation. You could cut the cable, and splice in whatever length you need, but then you probably would void the certification, which is not a good thing.

    The specs for that do not indicate the wire size or the current carrying capacity of the extension, but if it is from the same manufacturer, it should work fine. As said, though, often the connectors are the weak link.
  7. appdude

    appdude New Member

    Messages:
    36
    Location:
    Ontario
  8. DonL

    DonL Jack of all trades Master of one

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    Location:
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    That other CPS-EXT extension is fine.

    I solder and Heat shrink my strip connections, Them solder-less extensions look like trouble to me, But they may work.

    You need to use the exact type for the strip that you use, They are not all the same.

    A fuse is not necessary but I use a inline pigtail soldered and covered with heat shrink.

    3a_Pigtail.jpg


    What light strip are you using ?
  9. appdude

    appdude New Member

    Messages:
    36
    Location:
    Ontario
    I am using a 3528 led strip. And just to be sure, I am connecting the power supply above the microwave which connects to the led strip on the right of it. Then I'm using the led strip extension to connect it to the led strips on the other side of the microwave.
  10. DonL

    DonL Jack of all trades Master of one

    Messages:
    4,456
    Location:
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    That should work fine.

    I would solder things using the 18 Gauge wire that you have, then heat shrink the ends, just like they come from the factory.

    Flex cable solderless connectors may not be that great for the 2 amps that is required.

    If you go with solderless, please report back on how they work.


    I would not use them, unless I could not solder.
  11. Vegas_sparky

    Vegas_sparky Digital Billy

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    The extensions will be fine for any of the connections you have. Your runs aren't long enough to worry about overloading them, as long as the connections are secure.

    Don got me by that <> much.
    Last edited: May 5, 2014
  12. DonL

    DonL Jack of all trades Master of one

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    Location:
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    Yes, and do not use them to add another string, using the same power supply.

    Most of the 3528 strips that I have tested draw about 1.5 amps for a 5 meter 300 led strip.

    I like the 5050s but they do require a bit more power for the extra lighting power, but they seem to run cooler.

    The reason I use a fuse is for when the LEDs start to short out. Leds will normally short when they go bad. But the resistor for the bad leds will just smoke with no fuse, and 3 leds go out. When that happens you may be lucky not to burn up the strip. You can cut the bad LEDs out, or it is time to replace the whole strip.


    Have Fun
    Last edited: May 5, 2014
  13. Vegas_sparky

    Vegas_sparky Digital Billy

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    Location:
    LV,NV/ Nowhere,UT
    I only use 5050's anymore. Even though they typically have a lower chip density per lineal ft, the increased brightness makes up for it, IMO. Variable voltage power supplies help too. ;)

    Soldering/heat shrink is also my preferred connection, but without experience, its not always easy for someone to make a reliable connection. I typically use an 18/4 Belden(as shown)for my connections(sometimes CAT3), and yes, I do use black for the anode, just cuz. LOL

    [​IMG]
    Last edited: May 5, 2014
  14. appdude

    appdude New Member

    Messages:
    36
    Location:
    Ontario
    Solderless connectors in my opinion work great! I ordered [NO URL]
    connectors from **** to connect the power supply to the led strip and it works great. No issues at all. And one final question, I think the main led strip connectors have aluminum wiring in them. But the extension https://www.superbrightleds.com/mor...ies/18-awg-two-conductor-power-wire/535/1715/
    has copper wire in it. I've heard that joining copper wire to aluminum wire is not a good idea.
  15. Vegas_sparky

    Vegas_sparky Digital Billy

    Messages:
    382
    Location:
    LV,NV/ Nowhere,UT
    In this application a CU/AL connection is fine. The problem you've heard about is relative to larger materials where the different metals create harmful galvanic reactions, and experience thermal expansion differences.
  16. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,274
    Location:
    New England
    While the things could have AL wiring, it's more likely that it's tin-coated copper stranded wire.
  17. DonL

    DonL Jack of all trades Master of one

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    4,456
    Location:
    Houston, TX
    They can get by using AL wiring because it is not soldered, It is most likely crimped.

    If you cut the wire, It will need a crimp splice, because solder will not stick to it.


    Copper wire and soldering is the best. Even tho conductive Glue may work, For awhile.


    The RGB ones are good for a party, but a bit of a joke for usable lighting in a kitchen.


    Waterproof ones should be used, For best results.
  18. johnfrwhipple

    johnfrwhipple Bathroom Design & Build - North Vancouver, B.C.

    Messages:
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    Location:
    North Vancouver, BC
    Wow Jim. You know everything about Low voltage wiring as well? Amazing. From how to go pooh in Turkey to wire sizes on low voltage wire runs. incredible what goggle can teach someone.

    I work with LED lighting all the time.

    I have learn three important steps. Taught to me by my LED Lighting Guru.

    1). Any run over 10' should use solid wire

    2). Always solider your connections

    3). Always size the power supply properly. Most 2AMP power supply's do not cut it.

    4). Jim Debruyker goggles his answers so don't trust him (i just threw that in for fun. But I believe it)
  19. Vegas_sparky

    Vegas_sparky Digital Billy

    Messages:
    382
    Location:
    LV,NV/ Nowhere,UT
    The ACCENT lighting in my kitchen turns Don into more of a Grinch than a cat on top of my cabinets. LOL To imply anyone would use RGBs as TASK lighting in a sensitive area like a kitchen is the real joke.

    [​IMG]

    Doesn't make much sense to propose the act of having fun, and disparage those that do. :stickpoke
  20. DonL

    DonL Jack of all trades Master of one

    Messages:
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    LOL. I fell off of my rocker.


    Carry On.
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