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Rope CTs (technically called Rogowski Coils) are large, flexible sensors for monitoring current like split-core CTs. Rope CTs are installed similar to standard split-core CTs, where a connector on the rope allows it to be opened and placed around a conductor without needing to thread the conductor through it. For pricing and available models, visit the online store.

Follow the steps in this article to properly install rope CTs for your eGauge. 

Prerequisites

• Before beginning be sure to read all documentation and/or inserts that were included with your CTs.
• CTs purchased from eGauge will be compatible with your meter. If you purchased CTs from another source, check that they are compatible by reading our FAQ topic on CT compatibility.
• Supported CTs not purchased from eGauge Systems may not come equipped with 2-pin CT plugs. If needed, they can be purchased from our web store.

Instructions

Step 1: ERA-xxx-yyyy CTid enabled Rope CT -  Open the CT by gripping and twisting the bayonet connector and pulling the end of the rope CT out. Exact model with CTid logo is found on the tag attached to the lead. 

RCT-xx-yyyy AccuEnergy Rope CT- Open by gently squeezing the latching mechanism on the sides and pulling the CT open.  Exact and current rating is found on the tag attached to the lead. 

Step 2: Slide the CT over the conductor(s) of the circuit to be measured and close the connector securely.  Rope CTs should be positioned with the conductor as centered as possible. Twisting or distorting the flexible coil can contribute to inaccuracy. For more details please see our article regarding proper Positioning of Rope CTs

Step 4: Verify that the CT is fully closed by squeezing together the top and bottom parts of the CT. If the CT fits so tightly around the conductor that it needs to be forced close, the CTs should be replaced with a CT with a larger opening.

Step 5: Secure the CT to the conductor with a cable tie, if desired.

Step 6: Route the CT lead to the meter such that they do not directly contact live terminals or bus bars.

Step 7: Plug the 2-pin terminal at the end of the twisted pair wires into an unused port on the meter lining up the black and white leads with port markings as shown below:

Step 8: Using a handheld volt meter, verify CT phasing by taking a voltage reading between the monitored conductor and the eGauge AC Voltage ports. Check L1, L2 and L3 and make a note of the CT port used and the voltage port where you see a 0 VAC reading between points as shown in the graphic below.

Step 9: Record the eGauge sensor port used, CT model and Amp rating as well as the monitored load and phase verified in the previous step for reference. This information will be needed later for proper meter configuration. Use the Installation information pages in the back of the manual or create your own spreadsheet to record this information.

Example: 

Extending CT Leads

If AC CT leads must be extended, please follow these guidelines:

• 18 ga. twisted pair wiring, or Cat 5 cable (1 twisted pair per CT) is recommended.
• Splices should be soldered or completed using appropriate connectors such as the eGaugeCT Extension Pack. Wire nuts should not be used.
• Extensions recommended not to exceed a maximum of 100 feet.
• Avoid running alongside any high voltage wiring to reduce the potential for interference.

Troubleshooting and Tips

• Tip:  CT orientation direction matters, be sure to orient CTs consistently. Direction will affect polarity.
• Tip: If CTs do not close easily and need to be forced onto the conductors, they should be replaced with a larger CT.  CTs that are too tight will not read correctly.

Additional Resources