# Can Arduino ground handle 5A from an external common ground?

Howdy Everyone,

I’m currently building an LED strip that will have 80 WS2812B LEDs powered by an external power supply and the data pin coming from the arduino which will be connected to a computer via USB running some processing code to blink the lights along with music playing on the computer.

So far I’ve made it work but I have one question, does the Arduino Ground pin have a limit to current? From what I understand the LEDs need a common ground to work, I tried with separate grounds and it seemed the data pin was getting incorrect data (for example it was flashing white when it should have been flashing blue).
With the common ground the LEDs work perfectly but when I set them all up and I have the LEDs consuming a total of about 5A if the ground is common does that mean that there will be 5A going into the Arduino Ground? Will that fry the Arduino?

Also does the breadboard that comes with the Arduino starter kit handle 5A?

This is how I’ve got it setup: http://i.imgur.com/Ouw8wpJ.jpg

Many thanks

That's the way it's supposed to be connected. In this case Arduino pin is not handling 5A, the wire to the power supply is. The connection is there to bring both parts to the same potential.
It's not a good idea to run 5A through a breadboard.

The PSU is 5A, but if you load it with 5A for extended periods it might die sooner than you'd like.

Unless your PSU or components are specifically 5v, you may want to investigate using a higher voltage for your LEDs. It should require less current, but I don’t know the specifics, as I’m still learning… and LEDs are funny beasts.

So in theory if I was driving 1000 LEDs it would be fine as long as the power supply could handle 50A? The ground pin on the Arduino doesn't care how many amps are in the circuit coming from an external power supply?

And without using the breadboard, can I just solder 3 wires together?

The idea is to have the lights blinking with the music so 5A is the absolute maximum, on average it should draw much less than that.

FF56:
So in theory if I was driving 1000 LEDs it would be fine as long as the power supply could handle 50A? The ground pin on the Arduino doesn't care how many amps are in the circuit coming from an external power supply?

Yes. Correct.

FF56:
And without using the breadboard, can I just solder 3 wires together?

That would be a good way of connecting it.

FF56:
The idea is to have the lights blinking with the music so 5A is the absolute maximum, on average it should draw much less than that.

Sounds ok.