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CT load testing for Remote Power Panels

How to test your Remote Power Panels (RPP) for reliable data

Test Remote Power Panels before you start hooking up that load. UPS-backed power to servers in your mission-critical environment is critical. Accurate Critical Power Monitoring for these devices is crucial. Most manufacturers do a good job testing out their products before they ship.

When it leaves the manufacturer, many hands are working with these units. Once wired up on the floor, how do you know your remote power panel circuit monitor is working as expected. Using a small load (amperage), you can ensure your remote power panel monitor is working as designed. In this article, we cover some best practices with these critical devices.

Performing testing on Remote Power Panels verifies communications to the unit. It identifies any issues with the circuit monitor. Being current sensors are not working, and calibration issues. Apply a small load (amperage); you can test that your remote monitoring system is reporting correctly.

Verify communication to the unit

Once sitting on the floor, make sure it can communicate. Modbus communications is an open protocol used on this type of hardware.

Whether it is serial communications or ethernet, make sure it communicates. If the monitoring system is still under development, this is a prime opportunity to program and verify this RPP is solid. To point out, program the addressing scheme for the unit. Nevertheless, if the device is by APC modular remote power panel, Eaton remote power panel, or others, set up the communications before starting your testing when possible.

Serial Communications (RS485/RS422)

  • Configure the Slave ID, Baud Speed, Data Bits, Parity, and Stop Bits
  • Document how the connection from the serial cable
  • Provide a wiring diagram from the panel to the monitoring system
  • Scan the RPP to confirm the serial settings work
  • Verify communications at the highest poll speed possible to identify performance issues

Ethernet Communications (Network)

  • Program the IP address and Slave ID
  • Validate the network cable connected to the correct switch and port
  • Confirm the ethernet settings work by scanning the unit
  • Test the unit at the highest poll speed possible to identify performance issues

Visually inspect for any damage to the Remote Power Panel!

Next, the second step, make sure everything appears to be intact with the Remote Power Panel. Lots of hands will be part of the process of getting this critical electrical distribution device deployed. Damage during the installation process can happen. Components not connected or seated correctly during the installation can cause inaccurate data.

  • Check that the components are mounted correctly
  • Next, check the wiring for the communications between components
  • Look for any signs of physical damage or impact to components

Hook up a load source to the Current Transducers (donut)

To clarify, most Remote Power Panels use a solid-core current transducer (CT) or known as a “donut.” Once a critical load gets connected through this sensor, the only way to fix a board is to power down the panel. Hence, you must test out this style of current monitoring before the production load gets connected to it. Essential to realizing you ensure all BCMS components are working by wiring a static load to the panel. Heat guns, shop lights, and other small amperage loads work great.

Notably, breaker ratings on these panels are from 15 to 100 amps. Selecting a load source from 5 to 15 amps is perfect. When the panel is a Side-Side design, wire up the odd breaker side send the wire once through the donut. Loop the load wire twice around the upper donut. As a result, this checks the load through every current transducer, and the upper donut will have the load x2. This checks the board position and orientation. Follow the same setup with the even side of the panel. Straight panels follow the same process for each current transducer board set. Straight-style circuit distribution is commonly set up as circuits 1 – 12, 13 – 24, 25 – 36 and 37 – 48.

  • Use a meter to confirm the current (amperage) of the load source to be used
  • Using a load wire, 10 – 18 AWG THHN to route through the current transducers
  • The center of the donut should have the wire going through it once
  • Wire through the upper donut twice (Board Orientation)
  • Setup the odd-side and even-side independently

Verify the load using a software-based Solution

When getting closer to the actual testing process, you verified the BCMS communicates correctly. Second, wire up the load to the current transducer boards. Last you verified the load current (amperage) that will be the expected reading. If the Power Monitoring system is ready to talk to this panel, that is the best scenario. If the software used is not available, use a third-party software/tool to verify the readings.

  • When the Critical Power Monitoring system is not ready, use a third-party software/tool
  • Modbus Tools program Modbus Poll can log readings to a CSV file
  • CAS Modbus Scanner is a utility for scanning Modbus slave devices
  • Take screenshots when each current transducer board is under load
  • Ensure files and images get saved with a user-friendly reference name

Bring issues to the vendors’ attention!

The last step is to validate your readings. Make any known issues in front of the vendor. If a current transducer does not work, get a plan to fix it. When values are not within tolerance, have the vendor calibrate the transducer.

  • Create a punch list of open items to be addressed
  • Assign who is responsible for corrective actions
  • Dates for corrective actions

Given these points, testing Remote Power Panels before connecting your servers, storage, and other devices is critical. Most electrical contractors understand the benefit of doing this level of testing. When issues come to the surface, work with the manufacturer authorized vendors. Work to get a corrective action in place. When your staff can assist with this, it will save you money.

As shown above, when your critical power monitoring system is not operational, set up the communications to match what that system will be using. Include screenshots and data recorded from the testing. Proving the equipment was working from day one. Vendors providing this service can review what they use to capture data. The vendor may have a solution for long testing durations.

FMS Integration LLC understands not all applications are the same. If you have any questions, please feel free to contact us. FMS welcomes any technical or application questions.