What size cable tube should I choose for photovoltaic panels

Why 10-American-Wire-Gauge (AWG) is selected as the standard for external connection of solar arrays due to the following:Oversized for safety & voltage dropLow resistance for solar current of 30 Amps per single panelThe voltage drop over distance is lowCable is flexible [pdf]
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Solar power generation capacity per MWp

European deployment of has slowed down considerably since the record year of 2011. This is mainly due to the strong decline of new installations in some major markets such as and , while the and some smaller European countries are still expected to break new records in 2014. deployed about 350 MW (+18%) of (CSP. [pdf]