Wire is sized by the amperage that it is allowed to legally carry. To answer this question the amperage that you need at the garage must be stated. Also the distance to the garage must be stated. With this information the calculation can be made.
Need to know the wire size.
You need to know amps to answer this... Amps x Volts=watts
A "square foot" is a unit of area measurement equal to a square measuring one foot on each side. 1 Square Foot = 0.0929 square meters. Abbrev.: ft2, sq.ft, SqFt. To calculate the answer you need to know the exact length and width of your garage. Square footage of gargares vares. The garage for my home(2 car garage is is 21' long X 21'wide house was built 1956.
Need to know the voltage. Watts = Amps x Volts
Amps are related to voltage in the following equation: Watts = Volts * Amps; so in order to answer your question, one would need to know the wattage.
You need to mention the wattage of the fan to know the current.
They are not the same you need to know the voltage as well.
Need to know the wattage to work out the amperage
You would also need to know the current in amps. The formula you need is this: P = I V Power (in watts) = current (in amps) x voltage (in volts)
I have to know the amps and voltage of the garage door motor and the length of time the door takes to open and close to answer this question.
Need to know the voltage of the circuit.
There is no direct conversion between the two. You need to know voltage to calculate amps. This is the equation: P = V * I Where: P = Watts V = Volts I = Amps