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Thread: Pixel string wire gauge

  1. #31
    Join Date
    Oct 2014
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    Sauk City, WI USA
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    Default Re: Pixel string wire gauge

    I believe some US storefronts have just stopped providing wire specs. They got tired of the problem and so just avoid it by not advertising a spec.

    This is really the issue. A spec is a spec. It isn't an opinion (world's best pizza). It isn't "that is what it always has been". It isn't everyone knows we are lying (which isn't true). It isn't that is what everyone else is selling. It isn't "the wire would be too big" (that got a laugh out of me). Why not just be truthful about what you are selling?

    And it definitely could be a safety issue. 18 awg should handle 3.5 amps (*some random website with current load tables). But look how fast that drops off:
    Code:
    AWG	(mm)	Max. Current Load Ratings - Copper (amps)
    18	1.0	3.5
    20	0.81	2.5
    22	0.64	1.5
    At 22 AWG, less than half the current you should push on the wire as you would be permitted with 18 awg. That isn't a little difference. That is a huge difference. Even to us light guys.

    Twenty-five (yep just 25) 5V pixels are around 1.5 amps at full white (*adafruit). So, our general rule of thumb is that we put 50 on a string. Yikes. Then you "I'm okay with it" will say, well the lights are off more than half the time. I only run 50%. It is cold where I live. The specs are conservative (which they are for good reasons). Just excuses for not doing the right thing.

    Would this cause me to change how I do anything in my display? Probably not. But why not just be truthful about the specs?

  2. #32
    Join Date
    Nov 2014
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    Close to Hillsboro, OR
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    Default Re: Pixel string wire gauge

    I think this is a great conversation to have, even if we only point out that those of us that are in this hobby acknowledge that we are using products that aren't exactly living up to the description. The biggest thing that jumps out at me is that we all need to be aware of what we are working with and what could *possibly* happen if we overload our systems in our displays. Yes, there is a risk of fire or damaging our home electrical system. However, I think that we as a group are always quick to help someone with some tips, gotchas, and concerns when we see that someone could possibly be putting themselves into harm's way. My other thought is that if you are concerned about what you are receiving as a product, use this community to ask questions, and, odds are that someone here has run into a very similar situation and can help with making sure you aren't going to fry anything, including your home and, more importantly, YOU.

  3. #33
    Join Date
    Nov 2019
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    Default Re: Pixel string wire gauge

    Quote Originally Posted by MikeKrebs View Post
    This is really the issue. A spec is a spec. It isn't an opinion.

    Just excuses for not doing the right thing.

    But why not just be truthful about the specs?
    Indeed.

    I would like to have some certainty I know the specifications of what I purchased so I can use the product properly and safely. I can learn to work around the limitations imposed by the 22 AWG wire. It would have been nice to know ahead of time, before I ordered the pixels, that was the case. That 18 AWG specification was a differentiating specification and the reason I paid extra for the strings.

    With respect to the number of pixels, I am using 5V pixels and so it is a bit easier to deal with this issue because I am already planning injection that limits the maximum current in my strings to 3A (50 pixels). However, the users of 12V pixels may be at greater risk since they likely plan their power injection using a 100 pixel modulus. A string of 100 pixels at full brightness is 6A. And if you push more than 100 pixels well things can get dangerous pretty quickly since power dissipation is the square of the current. So, a doubling of the current is four times the power dissipation in the wire. A tripling of the current is 9 times the power dissipation in the wire.

    There are a few things the vendors could do to address this:

    1. Increase with wire size and actually make it 18 AWG.
    2. Use a silicone based insulation rated for a higher operating temperature (105 or 230 degrees C) instead of using PVC rated for 60 C.
    3. Embed DC/DC converters into the string (similar to how they do for strips) so you run the string at 12V and the current consumption more than halved.

  4. #34
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    Nov 2019
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    Default Re: Pixel string wire gauge

    Quote Originally Posted by XmasinVancouver View Post
    Steve don't misunderstand angus and bwinter, they aren't saying safety does not matter, and that electrical codes aren't there for a reason.

    Sent from my SM-N960W using Tapatalk
    Yeah, I think I understand what they are saying. I debated whether or not to even bring up the subject up because there is likely very little we can do individually to stop this behaviour. What might really help this hobby is if one of the mainstream retailers started to take a serious interest in this (Home Depot, Lowes, Walmart, etc). A major buyer could insist that quality standards are met and would have the wherewithal to perform quality inspections before the pixels left the factory. The problem is it is a highly technical undertaking to put this kind of thing together so not something likely to catch their attention.

  5. #35
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    Nov 2019
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    Default Re: Pixel string wire gauge

    Quote Originally Posted by Stormyblade View Post
    I think that we as a group are always quick to help someone with some tips, gotchas, and concerns when we see that someone could possibly be putting themselves into harm's way. My other thought is that if you are concerned about what you are receiving as a product, use this community to ask questions, and, odds are that someone here has run into a very similar situation and can help with making sure you aren't going to fry anything, including your home and, more importantly, YOU.
    Being new to this hobby I have found the community to be exceptionally patient and willing to provide tips and assistance. It has been an amazing experience.

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