August 6, 2026
In the intelligent retrofitting of power distribution systems in old buildings, the most frustrating problem for engineers is often not equipment selection, but power outages. In a building built decades ago, distribution panel drawings have long been lost, cable labels are seriously inconsistent with actual conditions, tenants cannot stop production, and the utility company requires time-of-use metering or energy monitoring retrofits to be completed by a deadline. Traditional current transformers require cable disconnection for installation, which means the distribution cabinet must be powered off. For factories with continuous production, data centres, or commercial complexes, a one-day power outage could mean hundreds of thousands or even millions of dollars in losses. The emergence of split-core current transformer is changing this situation.
In old distribution panel retrofits, the real trouble is never the equipment itself, but the "legacy issues" that surface only after construction begins. A typical retrofit project often encounters these situations:
Drawings don't match reality – About 10%–20% of circuits are not on the original drawings at all, having been added over the years by maintenance staff.
Labels are almost untrustworthy – Nearly one-third of distribution panel labels need to be re-verified and corrected.
Hidden distribution panels not on the drawings – For example, meter rooms sealed behind walls, or sub-panels that were never recorded but supply power to an entire floor – these can delay the project by weeks.
These hidden risks cannot be discovered before power-off construction begins. Once the power is cut, every extra day of downtime can mean hundreds of thousands or even more in lost production for a factory. Power outage cost is the most uncontrollable variable in any retrofit project.
The core design of a split-core current transformer lies in its openable core. Unlike traditional solid-core transformers that require cable disconnection, threading, and fixing, split-core transformers use a clamp-on structure. They can be directly snapped onto existing conductors and then closed and locked. The entire process requires no cutting of any wires and no power-off of the circuit under test.
Taking the SHINHOM SCTK751AT series as an example, its split-core structure supports power-off-free installation:
Split-core design: The core can be opened to clamp onto the cable without disconnecting busbars or powering off
Built-in precision resistor: Directly outputs a 0.333V voltage signal that can connect to various meters and protection devices
Multiple aperture options: Six models from SCTK751A to SCTK751F, covering current ranges from 5A to 5000A, suitable for different cable diameters
In actual installation, split-core transformers are far more efficient than traditional solutions. Installing one traditional solid-core transformer takes about 15 minutes (requiring power-off, busbar removal, threading, and fixing), while a split-core transformer takes only about 3 minutes with direct clamp-on mounting.
Take an industrial plant retrofit project as an example: 120 current transformers need to be installed. The plant's daily output value is 1 million RMB.
| Comparison Dimension | Traditional Solid-Core Solution | Split-Core Solution (SCTK751AT) |
|---|---|---|
| Installation Time per Unit | Approx. 15 minutes | Approx. 3 minutes |
| Total Construction Time | Approx. 24 hours (3 working days) | Approx. 6 hours |
| Power Outage Required | Yes, full power-off during installation | No, online installation without power-off |
| Production Loss (Based on 1M/Day Output) | Approx. 1M RMB | 0 RMB |
| Labour Cost Estimate | Higher (3 days * team) | Lower (1 day * team) |
| Total Cost Difference | Baseline | Saves over 1M RMB |
Conclusion: In terms of production loss alone, the split-core solution saves approximately 1 million RMB for the project – far exceeding the price difference of the equipment itself. Combined with lower labour costs, the overall benefits are even more significant.
![]()
The SHINHOM SCTK751AT series split-core current transformers are specifically designed for power retrofit projects, featuring the following characteristics:
Split-core structure – Installation without cable removal
Voltage output – Built-in precision resistor, outputs 0.333V standard voltage signal, directly connectable to multi-function meters, PLC, DCS, and other equipment
High-precision measurement – Accuracy class ±1.0%, meeting power monitoring and relay protection requirements
Wide range coverage – 6 models covering input ranges from 5A to 5000A
| Model | Input Current Range | Output | Accuracy | Window Size (mm) |
|---|---|---|---|---|
| SCTK751A | 5-200A | 0.333V | 1.0 | 50.8*53.3*15.0 |
| SCTK751B | 10-400A | 0.333V | 1.0 | 59.6*62.7*21.0 |
| SCTK751C | 50-630A | 0.333V | 1.0 | 82.5*85.1*25.6 |
| SCTK751D | 100-2000A | 0.333V | 1.0 | 121.0*127.0*30.4 |
| SCTK751E | 200-3000A | 0.333V | 1.0 | 118.0*133.0*24.0 |
| SCTK751F | 400-5000A | 0.333V | 1.0 | 146.0*190.5*35.6 |
The value of split-core current transformers does not lie in how cutting-edge the technology is, but in solving the core pain point that actually exists in retrofit projects: installation can be completed without power-off, reducing construction difficulty and avoiding production loss. For engineers and contractors involved in power distribution system retrofits, the SCTK751AT series provides a reliable, efficient, and safe current monitoring solution.