How to Replace 4 Lamp Two Rapid Start Ballast with One Instant Start

Light Fixtures with Two Ballasts

A 4 lamp fixture with two rapid start ballasts can be replaced with one 4 lamp instant start ballast. As seen below, connecting the 4 lamp instant start ballast to the four lamps can be a bit confusing. This is because the wire colors on the ballast and the lampholders do not match up on two of the connections.

On the 4 lamp instant start ballast diagram below, each individual wire is connected to a pair of individual wires on the lampholders. Two individual wires of the same color (blue or red) connect to each of the individual pairs on lamps 1 and 4. The other two individual wires of the same color (blue or red) connect to each of the individual pairs on lamps 2 and 3.
One of the yellow common wires connects to the common wires of lamps 1 and 4. The other yellow common wire connects to the common wires of lamps 2 and 3.

4 Lamp Two Rapid Start Ballasts Replaced with One Instant Start Diagram

4 Lamp Two Rapid Start Ballasts Diagram

Factory wiring