The versatility and functionality of a clamp meter for DC current measurement cannot be overstated. We can group every person into two ends of a spectrum in terms of electrical difficulties: the solution providers and the solution seekers.
Regardless of which end you belong to, one tool that will bring the solutions to those electrical difficulties to your fingertips is a clamp meter.
A clamp meter is an electrical device that makes measuring current flow in any conductor possible without direct contact with the current. Prior to the introduction of clamp meters, current flow was measured traditionally by cutting a live wire and inserting a test lead in the circuit.
In a bid to remove the dangers associated with current flow measurement, clamp meters were introduced.
Are you hearing a clamp meter for the first time? Or the use of this tool is a daily routine for you? There is so much you will find out in this piece, read on to discover these valuables.
The process behind the working of a clamp meter
Accurate and reliable current flow readings can be achieved by using clamp meters, but there’s a catch: there are two types. The AC and DC clamp meters.
AC clamp meters measure AC currents only, as the name suggests. On the other hand, DC clamp meters measure both AC and DC currents.
The clamp meter for DC measurement is, therefore, more versatile and that’s why we are talking about it. How then does it work?
DC clamp meters function solely based on the Hall Effect sensor. Thus, the device can provide accurate current flow measurement.
This means the Hall effect’s sensor must be present in the DC clamp meter for it to function effectively. The principle of a current transformer is usually deployed in the measurement of AC current only.
So, the sensor in the clamp meter responds to the changes in the magnetic flux by causing an increase in the amount of voltage across any conductor. Therefore, the amount of voltage is proportionate to the change in magnetic flux and thus the magnitude of current flow.
With the help of a digital converter, the DC clamp meter converts the readings detected by the sensor. This converted reading is what you have displayed on the screen as the value of the direct current flow in the conductor.
While the hall effect’s sensor is largely responsible for the workings of a DC clamp meter, the number varies from one device to another. High-end Clamp meters for DC current measurement have two sensors, while the cheaper ones have just one.
How to measure DC current with a clamp meter
Measuring current flow with a DC clamp meter can be done in a few easy-to-follow steps. Current flow is best measured on the separate wires (conventionally, red or blue) in a cable because if you measure the whole cable you will get Zero readings always.
This is because the DC clamp meter measures the difference between the currents. To measure current low, follow these steps,
- The first thing to do is to switch the clamp meter to the desired measuring range of current. Usually, clamp meters have different ampere ratings ranging from the maximum detectable current flow to Zero. For instance, a DC clamp meter with two ranges; 400A and 40A can detect between 0 and 400A. The closer the current flow to be measured is to a range, the more precise the readings will be.
- Press and hold the trigger button to open up the clamp’s jaws.
- Place the conductor to be measured in between these jaws and release the button to close the jaws.
- The current flow detected will be displayed on the screen. Always reset the clamp meter to zero after each reading because of the sensitivity of the Hall effect’s sensor.
- Remember the DC clamp meter can measure both AC and DC current, so always switch the mode to suit the current type to be measured.
Factors to consider before choosing clamp meter for DC current measurement
Since clamp meters can be essential in solving electrical difficulties, you should always lay your hands on the best ones available. This is because the best clamp meters have enough sensors to give you the most precise and dependable results.
Luckily, getting the perfect DC clamp meter isn’t difficult as you can choose from a lot of websites. The question is, how will you know which of the products is reliable and which cannot be trusted?
Knowing how annoying it can be to use a low-quality device, we have identified some of the factors to look out for before you choose a clamp meter for DC current measurement.
The most important thing you need to look out for is the level of safety the device provides. At least you are opting for a clamp meter to prevent exposing yourself to the dangers of using the traditional method of the current measurement.
Look at the build materials, the build quality, as they are pointers to how safe the device will be. Also, check for the absolute voltage, current, and resistance ratings. Higher ratings for these parameters mean you have a safer device on your hands.
Lastly, regulatory certifications are indications that the device can be trusted. Any clamp meter for DC current measurement without regulatory certifications should be thoroughly inspected before purchase.
2. Clamp Size
Sometimes referred to as the jaw size, the clamp/jaw is the end of the device that holds onto the conductor to be measured. The openings between the clamps can be as small as 17mm and as wide as 45mm.
Depending on the level of intended use, you can choose from this range. Also, clamps come in different sizes and thicknesses. These are some factors you must never overlook.
Heavy-duty clamp meters will have bigger openings and thicker clamp sizes.
3. Maximum Resistance Limit
As it is in most devices, the resistance of a camp meter determines how effective it will be in stopping current flow. The higher the resistance, the more difficult it will be for the current to flow through the conductors.
Usually, clamp meters have an optimum resistance limit of nothing less than 4 kilo Ohms (resistance is measured in ohms). Although there are models that can go as high as 10-kilo ohms and even 40-kilo ohms.
If you intend on using the clamp meter on heavy conduction instruments, then you should opt for one with a higher resistance limit. Otherwise, a small resistance will do just fine.
4. Max Ampere rating
In reiteration, clamp meters have differing ampere ratings. Ampere rating is a measure of the amount of current the clamp meter can possibly detect. This will help you determine how heavy-duty any clamp meter is alongside the maximum resistance limit.
For instance, in a home or project demanding 300 to 400-ampere ratings, purchasing a 1000-rated clamp meter is going overboard. Remember, your choice of clamp meter for DC current measurement depends on your project needs.
5. Crest Factor
The better you are at determining the level of efficiency of a clamp meter, the better the decisions you will make. Another factor to look out for in DC clamp meters is the crest factor; a measurement of the current waveform.
The crest factor is determined by checking the max ampere rating against the RMS (Root Mean Square) value. The crest factor is important in assessing a circuit for overload.
6. Backlit Screen
In this present age, you should not be surprised to see most devices digitalized. There are digital clamp meters.
However, the essence of this factor is for you, for convenient use during your projects. For instance, if you are working in a dark area, having a clamp meter with a backlit screen is a plus.
No difficulty seeing the readings and it will make taking measurements of the conduction easier expected. This is an added feature and should not be a deal-breaker.
Warranty is a quality control feature you should look out for. If a brand offers a 1-year warranty, they are simply saying, all things being equal, we are sure this device will work perfectly for a year.
And that’s a feature that screams quality to me. Although not every clamp meter comes with a warranty clause, you should tilt towards products with a warranty.
Sometimes 1 year of manufacturer’s warranty is offered, sometimes more. Nonetheless, always lookout for a warranty clause on any clamp meter you want to purchase.
8. Additional Accessories
Lastly, check for extra accessories besides the clamp meter itself. Accessories such as a dust-free cover, alligator clips, tiny LED lights are great additions and definitely come in handy.
Even better if you work in the field, far away from the conventional toolkit.
As much as some of these factors are highly recommended, a read of previous buyers’ reviews can give you more insights.
FAQs about clamp meter DC current measurement
Clamp meters are great tools for non-contact current measurements. Nonetheless, certain questions bother users. Let’s take a look at a few of such;
How accurate are clamp meters for DC current measurements?
Precision is the foundation for the study of clamp meters. There is literally no chance for error, so, it is quite reasonable to wonder how accurate these devices can be.
Higher level of accuracy means the device will display the closest rate of current flow on any conductor. Sometimes accuracy levels are indicated, sometimes they have to be determined.
Still, DC clamp meters are best at what they do and leave little or no room for errors.
How do you check the accuracy level of Clamp meters for DC current measurements?
On any DC clamp meter, you should look for the percent of reading to determine its level of accuracy. If it shows an accuracy of 1% on the reading of 100A; it means the actual current flow varies around 101 amps.
High-end clamp meters have detailed specifications for more precision levels.
Can you measure the voltage with a clamp meter for DC current measurement?
One of the versatile functions of a DC clamp meter is checking voltage, AC, or DC at the same time. Measuring the voltage is sometimes different from the regular AC/DC processes.
To measure voltage with a DC clamp meter, follow these steps:
- On the clamp meter, select between AC or DC volts;
- On the COM jack, install the probe for black testing;
- Repeat the step above for the red test probe, this time in the V jack;
- Using the tips of the probes connected already to the clamp meter, make contact with the power circuit source to be measured;
- Get the readings on the display screen.
Another functional feature is stopping the reading on the LCD by pushing the HOLD Button. Afterward, detach the meter from the live current.
What is the best clamp meter DC current measurement for HVAC?
HVAC engineers are one set of experts that require high-end clamp meters for their profession. For instance, in the US, most industrial equipment is rated at 460V.
Thus, a really powerful tool is needed for the current measurement of 460 VAC. For HVAC measurements, you can choose between flukes HVAC specific device for measuring Ohms, micro-amps (for flame sensors measurement), VAC, VDC, temperature, Amps. Because of the high-duty usage of these devices, they must be easy to use at heights above ground level (on ladders).
A clamp meter for DC current measurement clenches its jaw around any conductor to measure the rate of current flow. In summary, the clamp meter for DC current measurement is precise, safe, easy-to-use, highly efficient, and gets the job done.
A whole lot is going on around DC clamp meters, but you are no stranger to the process as we have discussed how clamp meters work.
While you can walk into any store or visit any website and order a DC clamp meter, the factors to look out for will help you make the best choice. Depending on these factors and your budget, having made the right choice, we trust you can map out electrical connections, measure the current flow without going the unsafe invasive procedures.
Undoubtedly, this piece has been educative, but without a sound understanding of the workings of electricity, stick to being a solution seeker.