After 3 Lamp Ballast is Replaced Option 1
The lampholders on the left side of lamp 2 and 3 need to be disconnected from each other and rewired as individual wires for the new parallel ballast as shown above. The lampholder on the right side of lamp 3 will be wired from Individual to common and connected to the lamp 1 and 2 right side common wires.
In the left image, the wire is wrapped around the fingers of the dominant hand as shown. In the right image the dominant hand is closed, while grasping the lampholder in the other hand. The wire is gently pulled while twisting the dominant hand until the wire comes out.
See page 2 for wiring options 2 and 3.
A 3 lamp series ballast can not be replaced with a parallel ballast without rewiring at least two lampholders. As you can see in the “factory wiring” diagram below, the left side of lamp 1 and the right side of lamp 3 have individual wires. The right side of lamps 1 and 2, and the left side of lamps 2 and 3 have common wires. This is typical series parallel wiring.
There are three options for replacing a 3 lamp series ballast with parallel. The first is shown below in option 1. Option 2 and 3 are shown on page 2 of this article.
Replace 3 Lamp Series Ballast with Parallel