Form 5S Meter Wiring Diagram

The Form 5S meter is a widely used meter for monitoring energy consumption in three-phase, three-wire systems, making it ideal for certain commercial and industrial applications. Understanding its wiring configuration is essential for proper installation and accurate energy measurement. This blog post accompanies a detailed wiring diagram above of the Form 5S meter when used in a 3 phase, 3 wire delta system without PTs, explaining its key components and connections. If the voltage you are working on is over 240v, it is recommended that PTs are used in conjunction with the CTs to lower the voltage you are exposed to. Also, make sure that your meter is rated for the voltage it will be subjected to.

Overview of the Form 5S Meter

The Form 5S meter is a meter form designed to measure electricity in systems with two hot phases and a neutral. This setup is common in medium-sized commercial settings, such as small manufacturing plants and retail stores, where a three-phase power supply is necessary for equipment or lighting systems. The meter can be self-contained or transformer-rated, depending on the load requirements. The meter base is an eight terminal meter base.

Key Features of the Wiring Diagram

  1. Voltage Connections
    The voltage inputs are connected to the two hot phases and, the third hot phase which is commonly referred to as the common. These connections ensure the meter can accurately measure voltage levels in the system.
  2. Current Transformer (CT) Connections
    For transformer-rated meters, the wiring diagram includes CT connections labeled X1 and X2 for each phase. These transformers reduce high currents to measurable levels, allowing the meter to accurately calculate energy usage.
  3. Line and Load Connections
    The diagram highlights the current flow from the line side (source) to the load side (equipment). Properly connecting the line and load ensures the meter records consumption accurately.

How to Use the Wiring Diagram

When installing or troubleshooting a Form 5S meter, the wiring diagram acts as a guide to ensure all connections are correct. For transformer-rated systems, pay close attention to the CT placement and polarity (X1 and X2) to avoid measurement errors.

Applications of the Form 5S Meter

The Form 5S meter is commonly used in:

  • Small manufacturing facilities
  • Retail stores with three-phase loads
  • Commercial buildings with medium power demand
  • Pumps
  • 3 phase, 3 wire Delta systems

Its flexibility and reliability make it a trusted choice for measuring energy in these environments.

Conclusion

Accurate wiring is essential for the proper functioning of a Form 5S meter. Whether you’re installing a new meter or troubleshooting an existing one, the accompanying wiring diagram provides a clear and detailed guide to ensure everything is set up correctly. By following the diagram, you can maximize the accuracy and reliability of your energy measurements. As always, verify everything before energizing.

For more detailed guidance, refer to the wiring diagram provided above!

Form 16s Meter Wiring Diagram

The Form 16s meter is one of the most commonly used meter forms to meter a three phase service. It is what is known as a self-contained meter, meaning that all of its parts are contained under the cover.

What type of service does a Form 16s meter?

The Form 16s meter is typically used to meter the 4 wire wye service. This service generally comes in two different voltage choices. It is normally available as a 120/208v service, or a 277/480v service.

Also, this meter is normally only used on services of less than 400 amps. A CL 320 Form 16s meter is used for 400 amp services, while a CL 200 Form 16s meter is used for 200 amp services and less.

Wiring diagram for Form 16s 4 wire wye meter

What kind of meter base does a Form 16s meter use?

This meter utilizes a seven terminal meter base. It is also very common to find seven terminal meter bases that have meter bypass capabilities. In this type of meter base there is generally a handle that must be raised in order to bypass the meter.

Some meter bases that utilize bypass handles actually open the jaws of the meter base allowing for easy installation and removal of the meter. One thing that you must remember when dealing with a meter base that has bypass capabilities is that both the top and bottom side (line and load side) of the meter base remain energized when the bypass handle is in the closed position.

Best Practices

Although Form 16s meters can be used in 277/480v services, my opinion is that this should be avoided whenever possible. The reason for this is that whenever the meter is installed and removed, there is a great potential for an arc flash. The better option for 277/480v services is to install a CT Cabinet and use PTs to step the voltage down to a safer level.

Form 12s Meter Wiring Diagram








The form 12s meter can be one of the more confusing meter forms out there. So, here I want to provide a form 12s meter wiring diagram in two different configurations. One is the 120/208 network service.  The other form 12s meter wiring diagram is the form 12s meter in a delta service.

Form 12s Meter Wiring Diagram Network Service

The form 12s meter can be used with the network service. The network service comes from taking two legs off of a three phase wye transformer and using the neutral. So, if you measure voltage from each phase to ground you should get 120v. Also, if you measure voltage from phase to phase you should get 208v.

This service is typically found in businesses that are located in a downtown area or businesses that are located in an industrial park. The reason for this is that many of these businesses do not require a full three phase service. So, the utility will pull two legs and a neutral off of the nearest wye transformer and call it a day.

Looking at the diagram you notice that there are two yellow terminals. These are either or terminals. Meaning that you connect the wire to one or the other in the meter socket. Also, some meter sockets do not come with this 5th terminal pre-installed. You have to purchase a 5th terminal separately and install it yourself.

With some form 2s meter sockets there are provisions to install a 5th terminal. The form 12s is also known as a self-contained meter. This means that the meter is installed in series with the load. Pulling the meter will also turn off the power.







Form 12s Meter Delta Wiring Diagram

For the form 12s delta wiring diagram we are going to talk about the service. This is the diagram for using a 12s with a delta service. Note that this is a three phase service. If you notice there is no difference in how it is actually wired. I used different colors here to denote the difference but it is actually physically wired the same way.

This could be a 120v, 240, or 480v delta service. My recommendation, as always, is against using a self-contained meter for voltages above 240v however. In the center of this diagram following the blue wire again this is an either or connection. You can connect the wire to the left center terminal or the bottom center terminal. Also note that the stab on the back of the meter is interchangeable.

Since this is a three phase service when measuring voltage across any of the three phases you should get the same voltage.

As always remember that the colors in the diagram are for illustration purposes only. You should always use the colors your utility uses.







 

Form 4s Meter Wiring Diagram








The form 4s meter is the meter form used to meter single phase three wire services. Below is the form 4s meter wiring diagram. As always remember that there is no standard on colors in the metering field. So, always use your company standard as far as the color code goes. The colors here are chosen at random so they show up in the drawing.

Form 4s Meter Wiring Diagram

For the form 4s meter wiring diagram let’s start at the bottom. Notice that we are going to be metering a single-phase three-wire service. We have two phase wires and a neutral. Make note that this is the same type of service that you find on most homes. The only difference is that it is larger. Homes are typically metered with a 200 amp meter base. Furthermore, anything above that normally requires CT’s.

Ok, so we have two phases. Using Blondel’s Theorem we know that since we have three wires we are going to need two CT’s. However, each CT is installed on a different phase. Remember that the orientation of the CT’s are important. The polarity marking needs to face back towards the line side or the transformer. Hence the old adage, “dot to the pot.”








Going up the diagram from the CT’s we have wires X1 and X2 on each CT. It is also important to note that X1 is connected to the meter socket terminals labeled “current in,” and X2 is connected back to the neutral. Wire these backwards and the meter will not register correctly.

Staying in the CT circuit we go to the current return terminals. These wires connect back to the neutral to create a return path for the current.

Voltages

After tracing out all of the current wires we trace out the voltage wires. Notice that in this case the voltage wires connect directly to the service wires. If we were using PT’s in this service we would connect the voltage wires to the PTs.

What voltage should you expect in this service? You should expect to see a voltage of 240v between each phase. Also from each phase to ground or neutral you should expect to see 120v. Now there are some odd 480v services out there that use this service so be aware.

Where do we normally see the form 4s?

The form 4s meter is a transformer rated, also known as a CT meter, and is typically installed on large residences who have 400 amp or larger services.

It is also found on large businesses with the same requirements. Also, it can also be found on temporary services. These can include saw services or temporary trailers for schools.






Form 2s Meter Wiring Diagram









By far the most commonly used meter in the United States is the form 2s meter. Here is a form 2s meter wiring diagram. I also want to offer some notes about the form 2s service here.









Where is the Form 2s Meter Installed

Being the most popular meter out there it comes as no surprise that the form 2s meter is installed on both residences and businesses. It comes in both regular Kwh only format and is available with a demand register as well. Regardless the meter socket for the form 2s meter is wired the same way.

The Form 2s Meter Wiring Diagram

Ok, now that we know where the form 2s meter is installed let’s take a look at the form 2s meter wiring diagram. Notice that the form 2s meter is what is known as a self-contained meter form. This means that the meter is in series with the load. So, when the meter is pulled out of the meter socket the power to the service will go off. Of course, this happens so long as there is not a bypass meter base installed.

Alright, the power comes in from the utility on the line side of the meter base which is the top side. There are two terminals that the two phase wires will attach to. These terminals connect to the jaws that hold the meter in the socket. The next thing that you notice is the neutral wire. The neutral connects to a lug that is normally but not always in the center of the meter socket. Continuing on we see the ground connection. Most meter sockets now contain terminals specifically for the ground wire. This wire is connected to a driven ground rod.

On the bottom side of the meter socket we have the load side terminals. This is where you connect the wires that go into the house and connect to the panel. Notice that you also have both phase wires and a neutral.

I also want to make note of the colors in this diagram. The colors were chosen so they show up on the diagram. Always be sure to follow local and national codes with regard to wire color codes.

Voltages

The most common voltage for this type of service is 120/240. This means that if you check the voltage between the two phase wires you should get 240v. And if you check the voltage from each phase to ground or neutral you should get 120v. If you are having problems with the voltage on this service check out this post on flickering and dimming lights to help you with troubleshooting.

Follow the link to find out how others have learned How to Wire a Form 2s Meter Base.







Form 9s Meter Wiring Diagram








One of the questions that I often get is about how to wire a form 9s meter and how to do a load check. 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. So, 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.