20mm
m
It means copper tube size. More specifically, the outer diameter (O.D.) of the pipe being referred to is the same O.D. as copper pipe.
If it is a pressure pipe, you would reduce the plastic down to the copper pipes size with reducer fittings and then use one to go to copper. If a waste line and the difference is not too great, you can use a rubber coupling that is the right size on each end and held on with hose clamps.
This depends on the size of the copper pipe and what class it is. For example, copper pipe half inch class 0 and copper pipe class 3 have a wide weight difference because the wall of the class 3 copper pipe is much thicker.
For a 200amp service you need number 4 copper
id means inside diameter, od means outside diameter, copper pipe and tubing is measured by the od, therefore the od the pipe or tubing will be the same as the id of the fitting
15mm (1.5cm).
3/4 in. -- but alot of older homes only have 1/2 in. pipe -- so all you can do is use what size you have will be fine
it is usually reffering to a fitting that is copper on one side and female iron pipe size on the other.
15mm six point socket or 15mm wrench
15mm
15mm approx.