Month: April 2017

Form 12s Meter Wiring Diagram

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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

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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

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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.







Form 9s Meter Wiring Diagram

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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.








Buy all Sell all Renewable Energy Metering

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A buy all sell all arrangement of metering Renewable Energy seems to be one of the more popular ways of metering solar power and wind power these days. But what is it? How does it work? Is is right for me?

What is Buy all Sell all?

Buy all sell all is a way for small scale renewable energy producers to connect back into the grid. This typically uses a two meter setup. One meter measures what customers are consuming and the other measures what they are producing. It is pretty simple really.

How does it work?

As stated, in a buy all sell all arrangement two meters are typically employed. Normally when we think about renewable energy we think about solar panels on someone’s roof. This is accurate but often times customers think that as soon as they put the solar panels on the roof their power bill will go down. While this can be the case in a net metering arrangement it is not the case in a buy all sell all arrangement.








Surprising to some is that in a typical buy all sell all arrangement the normal electric bill does not change. This may be confusing. But what we are saying by buy all sell all is that we are going to buy all of the power that we use from the power company as usual. Then, all of the power that our solar panels or wind turbines produce will be sold back to the utility.

One of the easiest ways to think about it is if the solar panels or wind turbines were physically located in another state. You are still producing the power but it does not reduce your bill.

On your power be you will get something like an avoided cost credit. This is paid at a predetermined rate set by the utility. Normally it is close to the wholesale rate they pay. So, if you pay $0.10 per Kwh they may pay you $0.05 per Kwh. This means that you are not getting the retail rate paid back to you.

Is a Buy all Sell all Arrangement Right for You?

If it is the only option available then yes. If net metering is available then it is probably a better option as you can trade retail Kwh per retail Kwh. Before agreeing to either or you need to make sure that you read your rates very carefully to make sure they make perfect sense to you.

Conclusion

Renewable energy metering can be confusing. You have buy all sell all and you have net metering. But which on is right depends on your circumstances and what is available from your utility.







Net Metering

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Net metering is often times a confusing topic for many. But, it does not have to be. Many people try to make it more complicated than it really is. Here I want to define what net metering is. I also want to talk a little bit about how it pertains to Renewable Energy. Finally I want to help you decide if net metering is right for you.

What is Net Metering?

Net metering is used when some form of generation is used on the same service where power is being consumed. Confusing right? As always, I want to use an example. First, let’s talk about the term “net”. To net something out means to subtract what is used from the whole amount. For example, if you had $100 worth of sales but you had $45 worth of expenses then you netted $55. The same thing works with net metering. If you are generating power, be it from a generator, solar panels or wind turbines etc., and you are putting that power back onto the grid we need a way to calculate what you consumed versus what you produced.

Net metering typically uses one meter. Using a traditional electro-mechanical meter you can actually watch the disc turn backwards when you are producing more than you are consuming. This is an analog way of doing the math for you. When you are consuming more than you are producing the meter turns the correct way. When you are producing more than you are consuming the meter turns backwards.

Net Metering and Renewable Energy

I could not talk about net metering and not mention the role it plays in renewable energy metering. Most likely the first thing that popped into you head when you read the words “net metering” was solar power. So, is solar power metered with net metering? The answer is yes. This was the most common way to meter solar power. It is easier to do from a billing stand point and can be less work all together. With other types of renewable energy metering separate billing accounts need to be set up for credits and it can be very confusing. Using one meter however, allows you to read the same meter just like you did every month. As far as billing goes it looks like the customer is using less every month.








However, not all utilities offer net metering tariffs for solar generation. That is unfortunate because from a customer’s view it is really the best of options for feed in tariffs. This is because you are trading retail Kwh for retail Kwh. What I mean is that if the rate that you pay for electricity is $0.10 per Kwh every Kwh that you avoid because of your solar panels or wind turbine reduces your power bill by $0.10 per each Kwh you produce.

Is Net Metering Right for Me?

It depends. If it is an option that is available to you from your utility then it is most likely the best option. There are many things to consider with the different rates that may be available but generally speaking, net metering is usually the best option.

Are you planning on trying to produce more than you consume? Many utilities protect themselves against this by making sure that they limit the size of your renewable energy service. They pay wholesale rates for electricity so why would they want to pay you retail for what you produce?

Conclusion

In conclusion, I hope this dispels the net metering confusion that is floating around out there. Normally one meter is used in this arrangement. This type of metering provides a simple and easy way for utilities and customers to enjoy the benefits of renewable energy systems. Also, if it is available where you are it is most likely the best option for you.