Month: February 2017

What is Electric Current and how it relates to Metering

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What is electric current? A good question indeed. What is the unit of measure for electric current? How can we measure electric current and the difference between current and voltage? And finally how does it relate to metering? These are the questions that will be tackled in this post. So, let’s get started with the first one.

What is electric current?

Electric current is the flow of electrons in a circuit. It is also what is used to power our stuff. Remember that in a circuit we have both voltage and current available. But, without the current flow our electrical stuff does not move. So, now that you know that electric current is the flow of electrons in a circuit what is the unit of measure used?

What is the unit of measure?

Current is measured using what are known as amperes, or amps for short. This is typically notated as an “A” in formulas but can also be notated as an “I”. This “I” stands for intensity of current. As with any unit of measure amps can be smaller or larger. So, it is not uncommon to see milliamps or kiloamps. Milliamps is typically notated as mA and kiloamps as kA. So, now that you know the unit of measure, how do you measure amps?

How do you measure Amps?

Amps, or electric current, are measured using what is known as an ammeter. An ammeter can come in a couple of different varieties. There is the common clamp on ammeter. The clamp on ammeter comes with a spring loaded jaw that enables you to open the jaw and place it around the conductors. This places the ammeter in parallel with the circuit. Clamp on ammeters can be found in digital and analog variants.

Another type of ammeter is placed in series with the circuit. These are typically found on multimeters. Also, when an ammeter is placed in series in the circuit it typically is not able to measure a very substantial load. Make sure you read the specs on your meter before you place it in series in any circuit.







How does electric current relate to Metering?

Ah yes, finally, the meat of the article. Electric current is very important to metering. This is because we are essentially measuring the changes in current flow. Remember that using Ohm’s law and the power formula that Watts = Volts x Amps. This means that the amount of watts used are in direct proportion to the amount of current that is being used. As the amps go up, so does the watts. As the amps go down so do the watts.

We as meter techs should know how amps relates to watts and how to convert amps to watts. We should also know how to go the other way and convert watts to amps. This will help us in troubleshooting with customers. Let’s have an example.

A customer is complaining of a high bill. You go to the meter and notice it is spinning pretty fast. So, you take the cover off the meter base and check the amperage. Let’s say that it is 30 amps. How do you convert this 30 amps to watts? Using Ohm’s law we plug in the numbers. Assume this is a 240v service. W = 240 volts x 30 amps = 7,200 watts. Let’s convert that to kilowatts and divide 7,200 by 1,000. We get 7.2 kw. This means that whatever the customer has on is pulling 7.2 kw and if left on for one hour it will use 7.2 kwh. A load like this could mean that an appliance like the air conditioning is not functioning properly and is running all day.

Conclusion

Electric current is one of the most important units we have in metering. It is measured by using ammeters and its unit of measurement is the amp. Using Ohm’s law we can convert amps to watts and back again.








What is Voltage and how it relates to Metering

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What is voltage? This is certainly an important term to know in the electrical field. You hear it all the time. What is the voltage on the machine? Or, can you check the voltage on that circuit? We hear it, we say it but, what is voltage and how does it relate to metering?

What is voltage?

The most commonly used voltage definition states that voltage is the difference in potential between two points in a circuit. What a definition of voltage right? Another way that voltage is defined is by talking about water. Some find it easier to understand the voltage definition when we talk in terms of water pipes. Voltage is the driving force in an electrical circuit. We can think of it as the pressure in the circuit. So, what is voltage? It is the driving force in an electrical circuit.

How is voltage measured?

Voltage is measured using a voltmeter. With a voltmeter we can choose two different points in the circuit to measure the difference in potential across those two points. The unit of measure for voltage is known as the volt. The volt is named after Alessandro Volta who created the first battery known as a voltaic pile.

How does voltage relate to metering?

Ah yes, the big question is, how do we use voltage in metering? Well, we have to remember that meters measure kilowatts. So, what does that have to do with voltage? To find the kilowatts, we first need to find the watts. To calculate watts we need to know the current and the, you guessed it, voltage. Using Ohm’s Law we know that power is equal to voltage times current or stated mathematically, P = I x E. There are several ways you can remember this formula. One is by remembering the word PIE. Another is to change the letters to W = V x A.








In the first example, P = power measured in watts, I = current measured in amps, and E = voltage measured in volts. Just a quick fact here, E is the letter used because it stands for electromotive force which is a fancy way to say voltage.

In the second example, W = watts, V = voltage, A = amps. So, the two equations are equal they are just using different terms. The easy way to remember W = V x A is to think of West Virginia or W VA. Pretty simple right.

So, now that we know the terms we need to know how they relate to metering. Well, the nominal voltage in a typical metering circuit remains pretty much constant. A common household voltage is 120/240. So, the meter measures this voltage and then multiplies the voltage times the current in the circuit to get watts. And then as if by magic the readout is in kilowatts.

What?

Look at the equations again and go back to algebra I. If the voltage stays constant and the amperage goes up that means that the wattage will go up. If the amperage goes down, the wattage goes down. To get kilowatts from watts, divide the watts by 1000. In the older electromechanical meters the voltage coil, also known as potential coil, produced a magnetic field in the meter. When current flows through the meter it produces a magnetic field as well. The interaction between these two fields are what causes the disc to turn. So this is why it is important to make sure that the meter chosen for each installation is crucial.

Conclusion

Voltage is the driving force behind each and every electrical circuit. We can use Ohm’s law to calculate watts using the power formula. It is the interaction of voltage and current in a circuit that causes the meter disc to spin. To check the voltage in a circuit we use what is called a voltmeter.









Portable Generators – All Your Neighbors Will be Jealous as they Sit in the Dark

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Portable generators are becoming a very popular way to keep the power on. There are many things that can knock the power out. The biggest being storms. Whether they are ice storms, thunderstorms or just plain windstorms, a power outage can be a major inconvenience. So what do you do? You go shopping for a portable generator. But, with all of the choices available where do you start? How many watts do you need? Do you need 120v or 240v? How do you connect it to your house?  Read on as we tackle these questions.

When Shopping for Portable Generators, where do you Start?

If you are keen on making your neighbors jealous when their power is out and yours is not, you need to start shopping and buy your portable generator before the storm. So, that is the first place to start. Make sure that you are not waiting on the natural disaster to begin shopping. Prices can be higher during a natural disaster and supplies may be limited.

You can do your shopping at many of the big box hardware stores or even online at sites like Amazon. There are several things that you need to consider when buying a portable generator. The biggest two are watts and voltage. When looking at these quantities you need to first decide what it is that you want to power when the power is out. Which leads us to our next point.

How many Watts do you Need?

To decide how many watts your portable generator needs to put out you first need to decide what you want to power. Do you want just lights so you can see at night? Does your refrigerator need to have power so your food does not spoil? Do you want to have heat? These are all considerations to take into account when deciding how many watts you need. All of your appliances have wattage ratings. So, decide what you want to power and then go and check the ratings of each appliance.

After you have checked the wattage ratings of your appliances add them up. This will give you the amount of wattage that your generator needs to put out. A word of caution here. Most people want to power their entire homes with a portable generator. While there are some models that are capable of doing this for smaller homes, that is not their intention. The intention is to run critical loads or essential loads. These are the loads that are most essential. If you live in a very cold climate your heating system may be a critical load. Most people choose their refrigerator and a few sets of lights as critical loads.








Should you buy a 120v or 240v Portable Generator?

The answer here depends on what you have chosen as your critical loads. If they are all 120v, such as lights and the refrigerator, then a 120v generator will work just fine. If you are wanting to power your heating system, water heater, or stove then you should consider a 240v generator. Some well pumps are also 240v. So, if you need to power a well pump you need to check the voltage of it as well.

How do you connect your Portable Generator to your House?

Connecting portable generators to your house is a job for a licensed electrician. They will install a transfer switch along with new breakers for the essential loads that you choose. This ensures that when the power does go out and you use your generator that no power will be put back on the grid. Keeping your generator power separated from grid power keeps the lineman safe.

Do not just fashion a drop cord with two ends that plug in and plug it into the wall. First of all this is illegal. Second, you can put power back on the grid this way and cause serious injury or death to someone working on the power lines. Also, if you do this you will try to run your whole house off of it. The extension cord is not rated for this and neither is the receptacle that you have it plugged into. You can burn your house down doing this.

This should be a no brainer, but make sure your portable generator is outside when using it. The exhaust from the generator can be deadly.

Conclusion

Portable generators can be a great addition to your home. They can keep the lights on and make your neighbors jealous. They can also be used to make sure that your food does not spoil during a storm. Make sure that when you are deciding what you want to power that you add up the wattage of each appliance. Then decide if you need a 120v or a 240v generator. Finally, once you have made your purchase, contact a licensed electrician to get everything installed in a safe and professional way.









 

Truper Automatic Wire Stripper Review

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An automatic wire stripper can really add to your arsenal of electric tools. The ability to quickly, easily and cleanly strip wire can increase your productivity and reduce waste. Until the automatic wire stripper came about, you really had two options. You could use your knife to strip wire, or you could use a regular wire stripper like the Klein Tools 11047 Wire Stripper/Cutter. What I want to do is give my review of the Truper Automatic Wire Stripper.

Using a knife to strip wire works but there is always the risk of cutting yourself in the process. There is also the risk that you may nick the wire and degrade its capacity. You can also use the standard wire strippers. They work well but there is some skill involved with those as well. You need to know your strippers to know which slots correlate to which size wire. There is also a risk of cutting into the wire as well.

Truper Automatic Wire Stripper

truper automatic wire stripperThese wire strippers can be used to skin wire from 22 AWG – 10 AWG. This gives you a very wide range of wire sizes to choose from. And the best thing about them is that they are automatic. This means that you will not need to squint really hard to see which hold in your regular wire strippers you need to use. You just lay the wire in there and squeeze. That’s it!

I have used normal wire strippers for most of my career. I have also used a knife to skin wire for most of my career as well. So, when I bought these automatic wire strippers I was a bit skeptical. But, they really do a great job of stripping the wire.

Details

truper automatic wire stripper jawsThe Truper automatic wire stripper features a guide that can be set up so all of your strips are the same length. This can be very useful for really anything you are doing. If you are making up a panel and you want all of your strips to be the same length so that just the right amount of bare wire is under the connector, you can do that. All you have to do is move it until you get the right length. Then set it and forget it. It really is that easy.

These automatic strippers also feature a wire cutter. However, it is not the best. It is located between the handles so you do not get a ton of leverage. When I was using them there were a few times where it did not cut all the strands of the stranded wire I was working with. But, these are not really made for cutting wire, they are made for stripping wire. If you are looking to cut wire then check out my review of the Truper Lineman’s Pliers.








Another feature of the this automatic wire stripper is the ability to crimp wire. It offers three different positions for crimping. Again, these are in the middle of the handles. I have never had good luck with any strippers or wire crimpers where the stripping, cutting or crimping is in between the handles.

The grips on these automatic wire strippers are comfortable. They offer plenty of leverage to carry out fast and precise wire strips.

Conclusion

The Truper Automatic Wire Stripper is a tool I wish that I would have had many years ago when I started in the meter field. I think about all of those meter bases I have wired up through the years where I used my knife or regular wire strippers to skin the wire. All of those CT’s and PT’s that I have wired up through the years could have been done much faster.

I highly recommend this tool. After using this tool on the first job you will not regret buying it. It makes stripping wire practically effortless.









Truper Heavy Duty Lineman’s Pliers Review

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Lineman’s pliers are one of the most important hand tools in a meter tech’s arsenal of tools. A good set of lineman’s pliers allows you to cut and bend wire with ease. They also need to be durable enough to be used at times as a hammer. Now, trust me I know that they are not a hammer but can you honestly tell me that you have never used your pliers to beat on something? One of the things that meter techs use lineman’s pliers for is cutting meter seals. Most of these types of meter seals have a steel wire which is harder than copper. This means that the pliers must be up to the task of cutting the steel day in and day out.

Now, I know that the Klein Tools 9-Inch High Leverage Side Cutting Pliers are pretty much the standard in the electrical field. But what if you need a set of pliers that work just as well but are different than everyone else? Are there any options out there?

Truper Heavy Duty Lineman’s Pliers

Truper Heavy Duty Lineman's Pliers

Truper is not a new company but it is not as well known in the electrical field as names like Klein, Greenlee and Ideal. But, they do make a good set of lineman’s pliers. Their 9″ heavy duty pliers are made of forged chrome vanadium steel which is supposed to be two times stronger than carbon steel. They also feature a good comfortable grips. The finish on the pliers is a satin finish which helps with rust resistance.







My Review

Truper Heavy Duy Pliers LengthSo, what do I think about the Truper Heavy Duty Lineman’s Pliers? All in all I think that they are a good tool for any toolbox out there. I do not think that you would be disappointed if you made the purchase. Now, there are a couple of things that I would like to mention about these pliers. The overall length is about 9.5″. The distance from the pivot point to the end of the handle is about 7.5″. This means that you get good leverage when using these pliers.

The grips are comfortable and they offer a raised portion to help aid in holding on to the pliers. I also feel like this helps keep your hands from slipping if you need to use the pliers to push something as well. I also want to note that the grips are not for use on live circuits. So, keep that in mind when using these pliers. I have used Klein Pliers most of my career and one difference that I notice between these and the Klein are that the head of Truper pliers seems to be larger. That could be a good thing if you are using the pliers to bang on things because of the added mass. It could also be bad if you need to get into tight spaces.

My biggest complaint with the pliers is the jaw design. You can see in the picture below what I am talking about. Just below the cutters there is a gap when the jaw open. More than once while using these pliers to cut wire the wire has fallen into that gap. This prevents you from cutting the wire because the gap portion clamps down on wire. Once you get used to it, there is no problem. Just something I though I would point out.Truper heavy duty lineman's pliers jaw

Conclusion

Would I buy the Truper Heavy Duty Lineman’s Pliers? The answer is yes. Although they are not perfect they are perfectly capable of handling any task with ease. Whether it be cutting, bending, pulling wire or wiring up CT’s these pliers get the job done.









Increasing Revenue with High Accuracy CT’s

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Increasing revenue is something that we all want to do. High accuracy CT’s can help us achieve that goal. When it comes to instrument rated metering installations we have to remember that our meter is only as accurate as our CT’s. So, the first step in making sure we are accurately measuring our metering installations is making sure we have the most accurate CT’s installed.

Standard Vs. High Accuracy

This is where high accuracy CT’s come into play. Remember that standard current transformers are only guaranteed accurate to within 0.3% from the nameplate value to the rating factor. Also, standard CT’s are 0.6% accurate from 10% of the nameplate value up to the nameplate value. This means that for a common 600:5 CT that anything below 60 amps is not guaranteed to be measured accurately. So, what do you do?

You install a high accuracy CT that is 0.15% accurate from 5% of its nameplate rating through the rating factor. Now, using the same 600:5 ratio as an example, we are now able to measure down to 30 amps with 0.15% accuracy. This is high accuracy CT’s are used to help with increasing revenue.

Where can high accuracy CT’s help with increasing revenue?

One of the places where high accuracy CT’s can help with increasing revenues are department stores or industrial factories that have been converted to warehouse space. These types of customer changes can cause revenue losses because the infrastructure that was put in for these larger customers who have now left or have converted their spaces is no longer being utilized.








Let’s say that the customer was doing some small scale manufacturing and decided that the space was no longer big enough for its manufacturing needs. So, they decide to move into a larger space and convert this previous space into warehousing. Let’s keep with the standard 600:5 for this example. For this example let’s also assume that the rating factor of this standard CT was three. We are also going to assume that we were using this rating factor. Meaning that this was a 1200 amp service and we installed 600:5 CT’s with a rating factor of 3, to make sure that the CT’s were as saturated as possible.

The customer in this example typically pulls around 750-800 amps. This is well within the range of our standard accuracy 600:5 CT’s. Now when they leave, they take all of the manufacturing equipment with them and only leave a few lights. There new load is now only around 40 amps. They do not need to heat or cool the space because what they are storing does not require it. So now, the standard 600:5 CT is not guaranteed to measure the 40 amps accurately.

What if we had installed a high accuracy CT?

If we had installed a high accuracy CT to begin with then we would not be worried. The high accuracy 600:5 CT is able to measure down to 30 amps with 0.15% accuracy. This means we capture those 40 amps and we do so accurately. This is how high accuracy CT’s play a vital role in increasing revenue.

Conclusion

In conclusion, if you are concerned with increasing revenue make sure that you are giving a look to high accuracy CT’s. They can be placed anywhere your standard accuracy CT’s are and can instantly start increasing revenue. High accuracy CT’s help mitigate low current situations such as when large customers move out or convert. If you are in the market for high accuracy CT’s check out Peak Demand.








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