Form 9s Meter Wiring Diagram

One of the questions that I often get is about how to wire a form 9s meter. Since I get this question so often I thought I would put up a form 9s meter wiring diagram. Here it is with comments about the form 9s meter wiring diagram below.

About the Form 9s Meter Wiring Diagram

The form 9s meter is one of the most commonly used meter forms. S0, as you begin to study the wiring diagram I want to make note of a few things. First is that the colors that I chose were chosen at random. That is because there is no universally accepted color code. You need to make sure that when you are doing the wiring that you adhere to your utilities color code.

If you do not have a color code then create one. You can use the colors above with some important changes. If you use colors that are the same you need to make sure you have a way to tell the difference between them. One way to do this is to use a red wire for one and a red wire with a black or white tracer for the other. This helps with troubleshooting especially down the road.

Remember that the form 9s is typically used to meter a 4 wire wye service. If you notice you have phases 1, 2, and 3 labeled as well as the neutral. You will also connect the metering equipment back to ground.

Wire Groups

So, what are the different wires? When wiring a form 9s meter you can think about the different wires in groups. You have phase groups and you have voltage a current groups. This means that each phase will have two wires. The voltage wire connects directly to the service wire in this example. The current wire connects to X1 on the CT.

Follow the black lines. The smaller black line connects to the voltage terminal in the form 9s meter socket and the thicker black line comes from the CT and connects to the current terminal. These make up one phase.

Remember that with the CT’s you need to make sure that the polarity marking or “dot” as it is often called needs to point back towards the Line. Remember dot to pot.

Bookmark the permalink.


  1. Steve Campbell

    I have an old 8A/10A as a substation meter. Tried to replace with 9s socket adapter and 9s meter when done the Vector plot shows all 3 I phases on the the Va phase 0 degrees. Reinstalled old meter and Vector plot looks ok. Suggestions?

    • My first thought is to check the adapter and make sure the wiring between it and the meter are all correct and that they are connecting to the meter in the correct place.

Leave a Reply

Your email address will not be published. Required fields are marked *