How much current is safe in a sealed up strand?

[Greg.Ca]

I am considering purchasing this particular strip:

https://www.aliexpress.com/store/product/4m-DC5V-addressable-WS2812B-led-pixel-srip-waterproof-in-silicon-tube-74pcs-WS2812B-M-with-74pixels/701799_32325613419.html?spm=2114.12010615.0.0.1u9w0b

It is a 4 meter long strip filled up with 5V WS2812b's at 74/meter. There are 296 TOTAL pixels in this strip which is sealed up in a waterproof 'jacket'. That means that there are 3X that amount of 'led's'. 296 X 3=888 total LED's. At 20ma each at full white that is 888 X .02= 17.76 amps/string.

Because these pixels are sealed up in a waterproof jacket, that means that the total number of pixels cannot be added or subtracted to. 296 total pixels in this waterproof jacketed 'strand'.

 I wonder if I even fed power at both sides, Isn't that too much current for those thin little traces in the strand?  Won't that eventually burn out those thin little traces if left on at full white for a period of time? Am I forgetting something or did I do my math wrong? Anything else I'm not considering?

Thanks to my 'pixel' buddies. I'm going to post this on several sites for better coverage and possibly better answers. --Greg--

[Dave Nibeck]

I didn't look at the link but I have cut many a silicone encased strips. Just need to seal the end with silicone (something type ii names escapes me) and shrink tubing.

Sent from my Nexus 6P using Tapatalk

[babybear]

Ok lets look at the math
  amps are equal to watts divided by volts
 The roll you are looking at only has a total of 296 LEDs for the 4 meters. Each LED is just over 1/2 apart. Each meter is 17.76 watts running at 5 volts so that's about 3.5 amps. now with 4 meters that's a total of 14 amps per roll. The rolls were designed to run that amount of power. The amps sounds like a lot but remember it only 5 volts. Think more of the Watts.  These lights are individual LED with each having its own chip. that means you can cut in between each one. The same strip at 12 volts you can not. There are 4 chips on the back side that reduce voltage on those. Once you cut a strip just fill in the end with a silicone caulk. I have done that for years. I'm using the a similar strip that's 60 LEDs per meter for my Ferris wheel. I'm cutting every 34th LED and soldering wires on to feed the data through to the next section.   

[Gilrock]

Those strips are designed to handle the current and that's why they are 4m long instead of 5m like a lot of other strips.  That being said I run my strips at 50% and they look great and are still plenty bright.  No reason to size for 100% white power.

[bwinter]

Ok lets look at the math
  amps are equal to watts divided by volts
 The roll you are looking at only has a total of 296 LEDs for the 4 meters. Each LED is just over 1/2 apart. Each meter is 17.76 watts running at 5 volts so that's about 3.5 amps. now with 4 meters that's a total of 14 amps per roll. The rolls were designed to run that amount of power. The amps sounds like a lot but remember it only 5 volts. Think more of the Watts.  These lights are individual LED with each having its own chip. that means you can cut in between each one. The same strip at 12 volts you can not. There are 4 chips on the back side that reduce voltage on those. Once you cut a strip just fill in the end with a silicone caulk. I have done that for years. I'm using the a similar strip that's 60 LEDs per meter for my Ferris wheel. I'm cutting every 34th LED and soldering wires on to feed the data through to the next section.   

When trying to determine the proper gauge of wire, you're mainly concerned with the AMP (passing through the wire) and DISTANCE....that will determine the necessary GAUGE.  Assuming proper insulation, VOLTAGE (and therefore WATTAGE) don't necessarily factor into the equation.  There are plenty of reference available to help with this:

https://www.bluesea.com/resources/1437

14 amps / roll is significant, so it's a valid question/concern.  You don't truly have 14 amps *going through* the entire roll...but it is recommended that you provide power from both sides (if using a full roll, and not cutting/sectioning).