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Many CNXTM current modules to supply testing power

Send us all of the CNX™ current modules you can spare!
Searching for testing power, Fluke turns to wireless CNX™ test tools

October 2013

The challenge was straightforward: find sufficient power in two fully-occupied service panels at the Fluke Service Center to drive power-hungry new infrared test equipment. And do it fast.

That or face the alternative - which would mean replacing the tapped-out existing utility transformer and installing new electrical service. That path would be time consuming, disruptive, and costly.

With no time to waste, the Fluke facilities maintenance team turned to one of the newest Fluke products, Fluke CNX™ Wireless Test Tools. In fact, they gathered together nearly two dozen CNX i3000 iFlex AC Wireless Current Modules and a3000 AC Wireless Current Clamp Modules for the project.

This is the story of how the Fluke team planned and ran an intense test cycle that compressed, into just a few days, tests that would normally take weeks…or months. It’s the tale of how they answered the challenge.

We need more power…Now!

Located just a few blocks from Fluke headquarters in Everett, Washington, the Fluke Customer Service Center handles the service and calibration of Fluke tools. Inside, the place buzzes with activity as Fluke technicians move about, putting a wide variety of instruments through complex test procedures.

Among those instruments are infrared thermometers and thermal imagers, and it’s their testing requirements that triggered a rush test project for Tanky Shiu, Fluke Facilities Engineering Manager, and Steve Ottman, Senior Mechanic and Chief Electrician.

The Customer Service Center urgently needed to add two new, high-powered infrared calibration devices, called “black bodies,” to those already in place. These black bodies use electric power - and plenty of it - to precisely heat their test surfaces. Infrared thermometers and imagers are then tested by measuring those surface temperatures, and calibrated to ensure the temperatures they report match those of the test surfaces.

The larger of the new black body calibrators consumed up to 60 A, and would require a separate 80 A, 208 V circuit. The smaller needed 40 A. But the 120/208 V service panels available to supply the new circuits were already full, their 42 breaker slots already occupied. Could any of the circuits be combined to free up space for the new breakers?

An unattractive alternative

It was a question of time…and big money. If the new equipment could not be powered through the existing service, the existing 300 KvA power transformer, which was running at 90 percent capacity, would have to be replaced, and new mains installed to serve the facility. That could cost $100,000 and take months to schedule, according to Shiu, and require shutting the facility down during installation. Shiu and Ottman knew there had to be a better choice.

Moving to the 225-amp service panel closest to where the larger black body would be installed, they used the Fluke CNX iFlex™ Wireless Current Module to log the current flow. “We set up the meter to look at the total draw for this panel,” Shiu said. “We saw it was using about 100 A, so we thought we could support the 60 A requirement.”

The next step was to examine the current flow through each of the panel’s 42 breakers. Most were rated at 20 A, though one circuit supplied a separate 100 A service panel. If under-utilized circuits could be identified that were located next to each other, those could be consolidated, freeing up space for a new 80 A breaker.

To find any variations in current draw that might take place throughout the workday, testing on each of the 42 circuits would cover a 24-hour period. But doing such tests one circuit at a time would take weeks - timing not acceptable to the infrared calibration team. As Ottman put it, “they want this done yesterday.”

“Engineering wise, we like to see as much data as possible, in one little window,” Shiu added. “Ideally we’d like to track it for a week, but we have to get this in.” So Shiu and Ottman put out the call all across Fluke: Send us all of the CNX current modules you can spare!

CNX to the rescue

Borrowing instruments from across various departments, they collected 21 CNX amp clamps and iFlex modules - enough to test half of the circuits in each target panel at once, and compress the tests into 24-hour periods. “The CNX is designed for more things than just logging,” Shiu said. “But the CNX is so flexible that it works.” Ottman installed modules on the first 21 circuits.

“The iFlex™ makes it real easy to install,” he said. “You should see how congested it is in there, even with the iFlex. If they’d all been hard clamps, it would have been almost impossible.” In fact, for the first test Ottman was able to place all 21 of the compact CNX modules inside the panel, and button it up for the night. Doing so wasn’t necessary for the testing, but it did make everything nice and tidy. The testers began logging.

The next day he returned, collected the modules, and downloaded the 24 hours of test results to his computer. The test results were then converted to Excel format, and turned over in table form for Shiu and Ottman to analyze.

“Having the CNX, where you could download the data, that’s beautiful,” Ottman said. “It saves a lot of time and effort on everybody’s part, and speeds up the process. Otherwise we could have been here for a week trying to chase this down, and maybe not even found what we were looking for.

“What we were looking for is the maximum that each circuit was pulling, because that’s the critical point,” Ottman said. “As long as the draw on these circuits is actually less than 10 A, we can potentially double up on them. What I’m shooting for is something less than 5 A. We identified several circuits that are pulling 1, 2, and even 3 A. Those are prime candidates for taking two circuits and combining into one. That frees up one slot in the panel. In this case we identified 19, 21, 23, 25, 27, and 29. They are all less than 4 A.”
Knowing the loads, now Ottman could consolidate circuit 23 onto breaker 21 and circuit 25 onto breaker 27. Removing breakers 23 and 25 opened up the two slots needed for the new 80 A breaker. Ottman popped it into place.

Space available!

“We needed to pick up two slots, so we looked at six consecutive circuits,” Shiu said. “On the circuits we picked, the max load was about 3 to 4 A on a 20 A circuit. So this morning we opened up the ceiling and started pulling wire. This afternoon we start the new conduit and wire for the new circuit.”

Circuit consolidation was made easier because 14 circuits were routed to a junction box installed above the ceiling near the service panel. “We lucked out on this one,” Ottman said. “Everything was in the proper J-box. And without CNX, we wouldn’t have been able to find all this out.”

Meantime the CNX modules were working again, logging loads in a second panel that would supply the smaller of the new black body calibrators. “We identified the 80 A circuit, so we are now doing analysis on the second panel to give us the 40 A,” Shiu said.

A plan for tomorrow

With the new black bodies supplied with power, the immediate problem was solved. But Shiu believes the power consumption data the team collected will also support long-term decision making about the building itself, since Fluke operations - and their power requirements - are constantly evolving.

“We needed to know exactly what we have,” Shiu said. “We always require power. This project gives us a database, so that we can approach power supply at the whole-building level. We have the data to present to upper management and the means to plan ahead.”

After four days of testing and wiring, power was available for the new infrared calibration stations. And though was a whirlwind job, Shiu looked back on the project with satisfaction.

“You hate to do the last-minute thing,” Shiu said, “but everybody worked together, from manufacturing to software engineering, hardware engineering to facilities and the maintenance guys. Everybody worked together to come up with a solution. It’s kind of fun!”

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