# Minimum wire gauge for 5 Volt, 5 Amp system

Electrical n00b here. I am trying to create a circuit with 100 ultra bright white/yellow LEDs in parallel (controlled via a rPi)

I figured out that I need an external wall wart, rated at 5V, 5A.

The project require minimum sized wires, I was wondering would telephone wires be "thick" though to handle 5V with 5A?

If not, what would be the recommended gauge of wire to use for this project?

• How long are the wires? Is there a series resistor for each LED? – Spehro Pefhany Jan 11 '15 at 16:24
• powerstream.com/Wire_Size.htm – Majenko Jan 11 '15 at 16:26
• Yes there will be a resistor for each of your parallel LED. The wires combined will be less than 3 meters. – Bill Jan 11 '15 at 17:05

I based that on a voltage drop of 0.5V (which will result in a change in brightness of about 25% with a white LED) and average (round trip) length of 3m, so resistance should be < 30m$\Omega$ per meter. It's also the NFPA ampacity recommendation for AWG 20.