why-calibrate

Types of Calibrations & Certificates

These days, any reputable manufacturer (or laboratory) performing a calibration will provide “NIST-traceable” calibration certificates, which denotes that the calibration accuracy is directly derived from the reference measurements of the National Institute of Standards and Technology (NIST). This is the bare minimum accuracy assurance that should be met by every company offering calibrations.

For power analysis equipment, regular calibrations are best practice for both the analyzer and the current probes. We offer three different types of certificates for both: a traditional calibration report certificate (CALIB), a calibration report certificate that includes “before” measurements, (CalCertB), and a calibration report certificate that includes “after” measurements (CalCertA). The traditional certificate is a document for your records that states that the equipment has been calibrated to the required accuracy specifications, thereby legitimizing any measurements you log with the analyzer and/or probes. The “Before” and “After” certificates are generally bought in tandem and they report the measurements before and after calibration to show the difference the calibration made. “Before” certificates are especially useful to verify the accuracy of measurements from a study that was already completed.

PowerSight Calibration for Flexible Current Probes

When sending eFX6000 flexible current probes in for calibration with PowerSight, you should be aware of what position we calibrate them in. As seen in the diagram, we calibrate them with the clasp in the 9 o’clock position. This is noteworthy because when installing these probes for testing, this is the most accurate position for monitoring current. It replicates the same conditions in which the probes were calibrated, providing the best results. If possible, make sure you connect your eFX6000 probes in this way every time. Please note that our other types of current probes are not particularly sensitive to their mounting position, just be sure their jaws are clean and closed when you install.

flex current probe calibration position
PS35550-connected-to-rope-probes

Why are Calibrations Important?

Over time, measurement tools like power analyzers may decline in accuracy. A regular calibration ensures measurement accuracy, kind of analogous to getting a car’s wheels realigned. Having verifiably recent-calibrated equipment boosts credibility and confidence in the testing you perform. You want to have confidence that the measurements you provide are accurate and can be used to justify making or not making changes to equipment and wiring. In fact, your clients and higher-ups expect that the measurement tools you bring to a project are correctly reporting statistics about power. It’s not uncommon for your results to be challenged if they provide unwelcome measurements. If that occurs after the study, you need to be ready by proving that the equipment was recently calibrated and therefore the measurements are to be relied upon. If challenged prior to a study, it can delay the study until a new calibration is obtained. This is harmful to the client and to your credibility. If the purpose of a test is to verify savings of a retrofitted system, don’t be surprised if you are challenged for the equivalent of our CalCertB (see above). The CalCertB provides a record of test measurements prior to calibration and therefore confirms that the analyzer was providing accurate measurements.

How Often Should You Calibrate Equipment?

The industry standard for power analyzers is to calibrate the analyzer and its probes once a year. If your PowerSight analyzer or system is kept under warranty, an annual calibration of the system is included, so calibration will not be an added expense to you. Our experience after thousands of recalibrations for our analyzers is that the analyzers themselves tend to keep their calibration fairly well over time, so the main need of calibration for the analyzer is to provide assurance that its measurements are still accurate. On the other hand, the current probes, particularly flexible current probes, tend to need the calibration during each year of use. Flexing of flexible probes and corrosion and aging of clamp-ons make them more susceptible to needing adjustment. You may be able to use your analysis system for multiple years without having accuracy problems but you are “rolling the dice” that the accuracy of the system has held up. So, if you use your PowerSight system multiple times a year and/or are relying on its accuracy for making important decisions, we recommend that you get it calibrated each year.

Furthermore, if you are considering a calibration, the best value is with our Warranty Renewal, which includes a calibration along with many other upgrades and benefits. Your analysis system can be calibrated by any calibration shop, but we’ll be happy to do it for you because we are invested in your success whenever using PowerSight.

The Cost of Calibrating Equipment

Calibration expense depends on where your equipment is serviced, which equipment needs calibration, and which certificates are needed. Most power analyzer manufacturers do not provide calibration service for their own units. If they do, they usually charge a fee for the analyzer by itself, plus an additional fee for each individual current probe. These costs can add up quickly and users can end up spending several hundreds of dollars on a single calibration for just one analyzer and set of probes. If done every year, these costs can negate any initial “savings” earned on buying a cheap power analyzer.

PowerSight calibration prices are transparent and inclusive. Visit our calibrations page to see our low pricing for different certificates. Keep in mind that our calibration prices are for a PowerSight system consisting of one analyzer and one set of probes, so you will not be paying extra for each probe. Moreover, PowerSight warranties include calibration service for the analyzer and probes in addition to repairs and firmware upgrades. Warranties for almost all PowerSight analyzers are renewable, over and over. We want to make sure you have the best use of our products for many years to come. No other manufacturer offers anything like this.