Technical Brief for Installation of Consumption Monitoring
Table Of Contents
- Assessing a Site for Installation of Consumption Monitoring
- For North America and Latin America
- About the Enphase Envoy-S Metered
- About Consumption Monitoring
- Consumption Current Transformers
- Site Assessment Form
- Circuit Detail Form
- 200A Consumption CT Dimensions
- Location of the Envoy-S Metered
- Installation of Consumption CTs
- Installing CTs in a simple scenario
- Installing CTs in Eaton Service Panels / Solar Power Center
- Installing Multiple Conductors in a Single CT
- Installing Parallel Connected CTs for 400A Services and Crowded Service Panels
- Calculating Whether Multiple Conductors Fit Within a CT
- Example Calculations for a Service Panel
- Retrofitting the Electrical Service for CT Installation
- Extending the Consumption CT Conductors
- Net Consumption versus Total Consumption
- Monitoring with the Installer Toolkit Mobile App
- Troubleshooting
- Viewing Sites with Consumption Monitoring
Installing Consumption CTs
2016 Enphase Energy Inc. All rights reserved. January 2016
9
Calculating Whether Multiple Conductors Fit Within a CT
Use a conductor fill calculation to determine if a given number of conductors can be installed within a single
CT. The NEC allows for a 60% fill calculation for conduit sections no longer than 24 inches. A 60% CT fill
calculation provides a conservative basis for calculating the number of allowed conductors.
Enphase consumption CT – cross-sectional area
100% Fill
60% fill (if multiple
conductors)
Enphase consumption CT
520mm
2
0.806in
2
312mm
2
0.484in
2
Dimensions of insulated conductors as specified in the NEC, Chapter 9, Table 5
Size and Type of Conductor
Approximate Diameter
Approximate Area
14 AWG THWN
2.819mm
0.111in
6.258mm
2
0.0097in
2
12 AWG THWN
3.302mm
0.130in
8.581mm
2
0.0133in
2
10 AWG THWN
4.166mm
0.164in
13.61mm
2
0.0211in
2
8 AWG THWN
5.486mm
0.216in
23.61mm
2
0.0366in
2
6 AWG THWN
6.452mm
0.254in
32.71mm
2
0.0507in
2
4 AWG THWN
8.230mm
0.324in
53.16mm
2
0.0824in
2
3 AWG THWN
8.941mm
0.352in
62.77mm
2
0.0973in
2
2 AWG THWN
9.754mm
0.384in
74.71mm
2
0.1158in
2
1 AWG THWN
11.33mm
0.446in
100.8mm
2
0.1562in
2
1/0 AWG THWN
12.34mm
0.486in
119.7mm
2
0.1855in
2
2/0 AWG THWN
13.51mm
0.523in
143.4mm
2
0.2223in
2
3/0 AWG THWN
14.83mm
0.584in
172.8mm
2
0.2679in
2
4/0 AWG THWN
16.31mm
0.642in
208.8mm
2
0.3237in
2
250 MCM THWN
18.06mm
0.711in
256.1mm
2
0.3970in
2
300 MCM THWN
19.46mm
0.766in
297.3mm
2
0.4608in
2
350 MCM THWN
20.75mm
0.817in
338.2mm
2
0.5242in
2
Based upon a 60% fill calculation, thirteen #8 THWN or thirty-six #12 THWN conductors can be installed
within a single CT.