Why Care About Ratio, Burden, and Admittance Testing on TC Installs?

Keeping transformer-rated installations within the operating range recommended by ANSI plays a critical role in the financial health of both utilities and their customers. ANSI C84.1 defines acceptable voltage tolerances, ensuring safe and reliable transformer operation, preventing inefficiencies and billing errors that can lead to costly repairs and financial strain​.

Current and potential transformers rarely have problems, but they can arise, whether due to magnetization of the CT over time, faulty wiring, a closed CT shunt, corrosion on the switches or a bad meter insertion at the socket. When these problems occur, costs quickly add up, and not just to fix the hardware issue.

Not to mention the hassle when it comes time to announce additional billing for backlogs to the customer, or an upward rate adjustment (sometime up to 300%) in order to rectify the situation.

On the other hand, when assessing an installation in response to a high bill complaint, utility companies could discover that they have been over charging their customers. When this happens, damage control is needed. But even after the utility fixes the problem and negotiates the amount to be reimbursed to the customer, the situation will have eroded trust in the company’s services and tarnished its reputation.

These types of problems can easily be detected when servicing a transformer-rated installation by performing CT/PT ratio, burden and admittance tests.

The chart above represents the impact of different types of testing and maintenance on transformer-rated installations, focusing on billing accuracy and cost-saving potential. Based on this data:

• CT/PT Ratio Testing has an 85% improvement in billing accuracy and 70% cost-saving potential.
• Burden Testing offers a 75% improvement in accuracy and a 65% potential for cost savings.
• Admittance Testing improves accuracy by 80% and provides a 60% cost-saving potential.
• General Maintenance has the highest impact on accuracy (90%) and the potential to save up to 80% of costs through improved operational efficiency.

Better safe than sorry!

With good planning, you can manage the risks that stem from these challenges. For instance, performing a full assessment, including ratio, burden and admittance tests on transformer-rated installations upon deployment as part of a routine quality assurance check. Then be sure to include it in your yearly maintenance plan, which is already mandatory in some states. To do so, an easy-to-use testing solution that fits seamlessly into your usual maintenance routine is vital…

In response to the ever-growing need for efficiency and portability, we proudly introduce the ST-3/XT3, the first socket-type transformer-rated site tester with integrated WiFi technology. it’s well-suited to the task and here’s why:

The portability and accuracy of the ST-3/XT3, paired with the advanced, yet intuitive Probewell Connect application is the best solution when it comes to testing transformer-rated installations.

Run all the required tests from a single measurement device weighting only 4.5 lb.

Main featurres of the ST-3/XT3 Wireless Site Tester

Click here to see the full technical specifications