If your APsystems microinverters are installed more than 6 feet apart, you will need extension cables to connect the string.
From the manufacturer:
Provides connection between microinverters on the same branch that are > 6 ft apart. Male connector on one end, female on the other. 12AWG, 600V, Type TC-ER, 90C, -40C. Insulation color: Red-Black-White. UL certified.