Single-ended LED tubes are not recommended because they have many installation restrictions and the wiring can be confusing. For single-ended direct-wired LEDs, line and neutral are connected to the lampholders at one end of the fixture. If shunted lampholders are used in the fixture, they must be replaced with non-shunted at one end of the fixture. Connecting line and neutral to a shunted lampholder will cause a short circuit. Tubes of this type can not be reversed in a fixture. A fixture modification label (should be supplied with the tube) is affixed to the fixture showing which end has power.
4 Lamp Instant Start Ballast (Wired in Parallel)
LED Single-ended Wiring Diagrams
For 4 lamp instant start fixture (ballast wired in parallel)
Lampholders on left side were replaced with non-shunted lampholders. Lampholders on the right have the original shunted lampholders.
How to Remove Wire from a Lampholder or Push-in Connector Video