Many threads have questions on recommended cables sizes for connection of DC power supplies to dimmers and LED lights and strips etc. There are a few items to consider such as the cable length, voltage used and current you need (may need to be measured). The table shows recommended cable sizes (copper wire cross section area) for the commonly used voltages for Blinky DIY lighting. In most cases you can safely double the cable length (you just increase the voltage drop > 4%) but for low voltage pixels and cases where the voltage is critical try to avoid this. You can also put smaller sized cables in parallel (just total their cross sectional areas).