ION 7650 different trends based on the electricity usage now in Line with each other

[om1301]

Hello all,

I wonder could you assist 

An End User is having Issues with 2 x IONs (7650) on site since the summer shutdown.

Prior to the shutdown the trends were as expected, different trends based on the electricity usage in different manufacturing areas on pre shutdown. However, since the summer shutdown, the trends are very much in line with each other (see pictures attached)

Also, the monthly bills versus the IONs are showing the same electrical usage on site

Has anyone come across this before and could assist ?

We have asked for a few Simple checks already

1) External Meter to check the IONs - Response "checked the bills against the IONs (4 x individual IONs) and the difference <1%."

2) Have you checked the CTs and their connections - Will be checked

3) Although unlikely that any setting changes has occurred can you check the Phasor Diagram on the IONs - Will be checked 

[Charles_Murison · Accepted solution]

Hello @om1301 , Is it possible, that during the shutdown, there was some electrical work that was done that could possibly account for the change? Loads rewired?
The suggestions you have made are all of the suggestions I would make as well. A difference between bill and meters being <1% is pretty good. 

Regards,

Charles

[om1301]

Thanks Charles, We are awaiting the results of an Audit by the Electrical contractor - appreciate the feedback. 

[Charles_Murison]

Hello @om1301 ,

Did the audit find anything?

Regards,

Charles

[chloewatson]

It’s possible that during the shutdown, the plant’s electrical configuration or load distribution was altered without being properly documented. Even a minor change in CT orientation, wiring, or load reallocation can cause two ION 7650 meters to show very similar trends, especially if they’re now monitoring circuits that share a common feeder or transformer.

In a similar situation at a manufacturing site, the issue turned out to be a CT polarity swap after maintenance, which made both meters read almost identical usage despite serving different areas. Once corrected, the readings diverged again as expected.

If you’re still seeing matching trends after verifying CT connections and phasor diagrams, it might help to have an experienced industrial electrician perform an on-site audit of the metering setup to ensure all phase references and CT ratios are correct. You can click here to connect with Electrician Singapore, who specialize in advanced metering systems and power quality diagnostics, they’ve handled similar synchronization and configuration issues in multi-meter installations.

This kind of expert inspection often reveals subtle wiring or parameter mismatches that typical checks can miss, especially after a major shutdown or system reconfiguration.