Electric (wire) cable working current formula: Single-phase current calculation formula I = P ÷ (U × cosΦ) P-power (W); U- voltage (220V); cosΦ- power factor (0.8); I- phase line current Three-phase current calculation formula I = P ÷ (U × 1.732 × cosΦ) P-power (W) U-voltage (380V) cosΦ power factor (0.8) I-phase current (A) General copper wire safety cut-off of 5-8A / mm2, aluminum wire cut-off for the safety of 3-5A / mm2. In a single-phase 220V line, the current per 1KW of power is about 4-5A. In the three-phase load balanced three-phase circuit, the current per 1KW of power is about 2A. In other words, in a single-phase circuit, each 1 mm 2 of copper wire can withstand 1KW power load; three-phase balanced circuit can withstand 2-2.5KW of power. However, the greater the working current of the cable, the smaller the safe current per square millimeter can withstand. Cable allows the safe working current formulas: Ten under five (ten or less by five) One hundred two (hundred or more times two) 23,543 (25 multiplied by four, 35 multiplied by three) Two and a half times for 7095 (multiplied by 0.55 for 70 and 95 lines) Wear tube temperature eighty percent (with the temperature changes, in the calculation of the safe current multiplied by zero eight or zero nine) Copper upgrade calculation (in the same section of the aluminum core line up one level, such as two five copper core wire is in the 2.5 aluminum core up one level, according to four square mm aluminum core line count) Bare wire plus half (in the original number has been considered a good number of safe plus half) Automotive Equipment Flat Key Membrane Switch Automotive Equipment Flat Key Membrane Switch,Buttons Touch Switch,Embossed Menbrane Switch,Tactile Button Touch Switch ZDX (HK) LIMITED , https://www.zdxmembranekeyboards.com