Wire (solid/stranded, by AWG/mm2)
Wire
A flexible conductor used to connect components in a circuit. Available as solid (single core) or stranded (multiple thin cores) with gauge determining current capacity.
What it looks like
Wire (solid/stranded, by AWG/mm2)
A typical wire — exact shape, colour and markings vary between manufacturers.
Types & variants
Key specs
Gauge
AWG (American Wire Gauge) or mm²Thickness of the wire. Lower AWG or higher mm² = thicker wire = more current capacity.
Current rating
Ampere (A)Maximum current the wire can safely carry without overheating. Depends on gauge and insulation.
Insulation type
MaterialOuter covering material (PVC, silicone, Teflon) that determines temperature resistance and flexibility.
Conductivity
% IACSHow well the wire conducts electricity. Copper is typically 100% IACS, other materials less.
Laws that govern it
- Laws of resistanceR = ρ × L / A
R = ρL/A is literally the wire table: double the length, double the resistance; go up two AWG sizes and halve it.
- Joule's law of heatingH = I² × R × t
Ampacity is a heat limit, not a magic number — I²Rt in the copper against how fast the insulation can shed it.
- Ohm's lawV = I × R
Volt drop over a long run is I × R, which is why a 12 V LED strip is dim at the far end and why 3 % drop is the usual design ceiling.
For anything long, the economical cross-section is where the cost of the energy lost equals the annual cost of the extra copper.
Each law is stated in full — with its diagram, variables and worked meaning — on the electrical laws page.
Markings
Wire gauge printed on insulation (e.g., '22AWG', '0.5mm²'). Color coding varies by application (e.g., red=positive, black=negative).
Standard values
Common AWG: 22, 24, 26, 28, 30. Common mm²: 0.2, 0.5, 1.0, 2.5. Match to current requirements.
How to choose
1) Determine required current capacity. 2) Select gauge with rating > expected current (add safety margin). 3) Choose insulation type for environment (temp, flexibility). 4) Pick solid for fixed connections, stranded for flexibility/movement.
Pinout & package
Single conductor with insulation. No polarity unless color-coded. Available in spools or pre-cut lengths with stripped ends.
Example circuits
- Power connections to components
- Signal wiring between boards
- Ground connections
- Battery leads
- Speaker connections
Common failures
Insulation damage (exposed conductor), breakage (especially solid core), corrosion at ends, overheating from undersized gauge.
How to test
Set multimeter to continuity mode. Touch probes to both ends of wire (should beep) or measure resistance (should be near 0Ω). Check for breaks or high resistance along length.
Substitutes
Use same or larger gauge wire. For stranded, can substitute with solid if flexibility isn't needed. For high-current, parallel multiple smaller wires.