The Enphase 200A CT Clamp (model CT-200-CLAMP, also known as CT-100-SPLIT / EN-CT-100-SPLIT) is a split-core current transformer designed for whole-home consumption monitoring in Enphase IQ systems. Compatible with the Enphase IQ Gateway Metered and IQ Combiner products, a pair of these CTs provides accurate real-time consumption data visible in the Enphase App. This model is rated for up to 200A primary current and is specifically sized for properties with 25mm² meter tails (up to 50mm² cable OD), which are typical of UK properties with a 200A incoming supply. Accuracy is within ±1%, certified to UL2808 with service entrance rating.
Split-Core
Clamp-On Design
-40 to +85°C
Operating Temperature
⚠ Electrical Safety — Qualified Installers Only: Installation of CT clamps must be carried out by a qualified electrician. Always de-energise the main load panel and the PV system before installing CTs. Never install CTs while current is flowing in the sensed circuit. Always connect CT wires to the IQ Gateway terminal block before energising the sensed circuit. Risk of electric shock if procedures are not followed.
⚠ Arrow Orientation Critical: Each CT must be installed with its directional arrow pointing toward the load (away from the grid). Incorrect orientation will result in incorrect consumption readings and may affect system behaviour.
ℹ Phase Matching: When installing for two-phase consumption monitoring, ensure the CT on each phase is connected to the matching C1 or C2 terminal on the IQ Gateway. Always verify phase assignment using a multimeter if wire colour coding is ambiguous — do not rely solely on wire colour.
Split-Core Clamp Design
The split-core (clamp-on) design allows the CT to be installed around existing meter tail conductors without disconnecting the cables. The core opens and closes around the conductor, significantly reducing installation time compared to solid-core CTs and avoiding the need to break the supply circuit beyond the normal de-energisation process.
Pollution Degree 3 Rated
Rated at Pollution Degree 3, these CTs can be installed inside electrical equipment in both residential and harsh industrial environments. This rating covers environments where conductive pollution may occur — making them suitable for consumer units, distribution boards, and commercial service panels.
Enabling Home Energy Management
When a pair of CT clamps is installed and connected to the IQ Gateway Metered, the Enphase App gains real-time whole-home consumption monitoring. This allows homeowners and installers to see exactly how much energy the property is consuming, how much the solar system is generating, and how much is being exported or imported from the grid.
Multiple Conductor Support
Where necessary, the CT aperture can accommodate multiple same-phase conductors bundled together, provided all conductors are on the same phase and physically fit within the aperture. This is useful in installations with multiple incoming conductors or parallel-connected service feeds.
| Technical Specifications — Enphase CT-200-CLAMP |
| Model Number |
CT-200-CLAMP (also referred to as CT-100-SPLIT / EN-CT-100-SPLIT) |
| CT Type |
Split-core clamp (clamp-on) |
| Accuracy |
<1% (±1%) |
| Max Primary Current |
200A |
| Turns Ratio |
2400 |
| Primary Voltage |
250VAC |
| Frequency |
50–60 Hz |
| Conductor Aperture Diameter |
0.87 in (approx. 22 mm) — suitable for meter tails up to 50mm² |
| Physical Dimensions |
2.75 × 2.12 × 0.61 in (approx. 70 × 54 × 15.5 mm) |
| Operating Temperature |
-40°C to +85°C |
| Humidity |
Up to 95% |
| Pollution Degree |
3 |
| Compliance |
UL2808 (service entrance rated), RoHS |
| Compatible With |
Enphase IQ Gateway Metered, IQ Combiner (with PCBA), Envoy-S Metered |
How many CT clamps do I need for a standard residential installation?
A standard single-phase UK residential installation requires one CT clamp per live conductor you wish to monitor. For whole-home consumption monitoring you typically need two CTs — one for each line (L1 and L2 in North American terminology; UK single-phase properties have one live conductor, so may require just one, but confirm with the IQ Gateway installation guide for your specific configuration).
Do I need this CT for a three-phase Enphase installation?
For three-phase UK installations, one CT per phase is required for consumption monitoring. This CT is sized for 200A meter tails (up to 50mm² cable). Confirm with the Enphase 3-phase IQ Gateway installation guide for exact CT placement requirements on your specific switchgear.
Will this CT fit standard UK 25mm² meter tails?
Yes. The CT aperture is rated for conductor cables up to 50mm², making it suitable for standard UK 25mm² meter tails as well as heavier gauges up to 50mm². It is the recommended CT for properties with a 200A incoming supply.
Can the CT be installed without interrupting the power supply?
The split-core design allows the CT to be clamped around the conductor without disconnecting the cable. However, the panel must be de-energised before connecting the CT wires to the IQ Gateway terminal block. A qualified electrician must assess whether de-energisation requires the DNO to be involved depending on the meter arrangement.
