The following information is for a licensed electrician to review and perform.
When your electric meter is installed, it relies on the orientation and wire landing associations for accurate measurement. It is best to refer to the CT documentation, labeling, and meter documentation to ensure polarity and phasing is as expected. For the smoothest installation experience, it is recommended to label both ends of the CT wire for traceability, and create documentation which will denote
On other meters with more than 3 CT inputs, it is best to follow this convention all the way through unless there are exceptions. In the case of split-phase loads, install the CTs where each odd input # is associated on phase A, and evens on phase B.
Once programming of the input matches that of the installed CT, one can use an amp clamp to potentially compare the CT measurement against the hand tool. This may not work in all cases but if the load is continuous, very resistive and is at least 1% of the CT size, it can be used to troubleshoot CTs quickly in the field.
If most inputs are working as expected but a few or not, try moving swapping wire landings from known "good" CTs to the landings of the CTs in question, and vise-versa. If the issue follows may help chase down the unexpected measurement anomaly. It is also possible to swap them at the CT side as well.
There are wire tracing tools that can be used which also may be useful to check circuit naming between the load and the panel where the CTs are installed.
In situations where the CTs need to be traced, one can perform a CT flick test to confirm the wiring at the other end is associated with a specific CT.
Important notes that you should be aware when performing a flick test is that they:
The needle will move from the 0VDC position and "flick" slightly towards the positive or negative direction when the battery is energized in the circuit. Be sure to maintain polarity throughout the test setup.
When your electric meter is installed, it relies on the orientation and wire landing associations for accurate measurement. It is best to refer to the CT documentation, labeling, and meter documentation to ensure polarity and phasing is as expected. For the smoothest installation experience, it is recommended to label both ends of the CT wire for traceability, and create documentation which will denote
- every CT input # to the meter
- which electrical phase the load is that the CT is monitoring
- CT part number wired to that input
On other meters with more than 3 CT inputs, it is best to follow this convention all the way through unless there are exceptions. In the case of split-phase loads, install the CTs where each odd input # is associated on phase A, and evens on phase B.
Once programming of the input matches that of the installed CT, one can use an amp clamp to potentially compare the CT measurement against the hand tool. This may not work in all cases but if the load is continuous, very resistive and is at least 1% of the CT size, it can be used to troubleshoot CTs quickly in the field.
If most inputs are working as expected but a few or not, try moving swapping wire landings from known "good" CTs to the landings of the CTs in question, and vise-versa. If the issue follows may help chase down the unexpected measurement anomaly. It is also possible to swap them at the CT side as well.
There are wire tracing tools that can be used which also may be useful to check circuit naming between the load and the panel where the CTs are installed.
In situations where the CTs need to be traced, one can perform a CT flick test to confirm the wiring at the other end is associated with a specific CT.
Important notes that you should be aware when performing a flick test is that they:
- can only be performed on our 100mA and .333VAC output CTs
- should only be performed with the CT removed from the panel, not landed or associated to any circuitry other than shown in the diagram below
- a handheld transformer polarity tester (recommended)
- component parts
- Low voltage DC battery, 9-12VDC
- Spare wiring, alligator clip ends may help
- Analog multimeter
The needle will move from the 0VDC position and "flick" slightly towards the positive or negative direction when the battery is energized in the circuit. Be sure to maintain polarity throughout the test setup.
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| Example wiring to perform a CT flick test |