Short answer: A clamp kWh meter for a single appliance is only useful when the instrument's documented ranges and installation method match the circuit being assessed. The product page lists a single-phase energy meter with AC 40.0-300.0 V, AC 0-100.0 A, current up to 100 A through an external CT, energy to 99999 kWh, frequency 45-65 Hz and power factor 0.00-1.00. Accuracy is class 1 (1% ± 2 digits). Voltage goes to terminals 1 and 2, and the CT secondary goes to terminals 3 and 4. HSE guidance says electrical equipment and work must be suitable and carried out by competent people where the task requires that competence.

Start with the measurement question

For one appliance, decide whether you need voltage, current, instantaneous power, accumulated energy, frequency or power factor. The product page lists all six parameter types and gives the published ranges, so it can support a comparison table. Check that the appliance circuit is single phase, within AC 40-300 V, and within the external CT range up to 100 A.

A single-phase label narrows the product description, and you still check that the supply is single phase, AC 40-300 V. HSE says electrical equipment should be suitable for the electrical supply and the task. Treat that as a planning requirement for the person who fits the meter.

Published parameterRange shown on the product page
VoltageAC 40.0-300.0 V
CurrentAC 0-100.0 A
Electric powershown as watts
Energy0-99999 kWh
Frequency45.0-65.0 Hz
Power factor0.00-1.00 PF
Product use sequence

Check the appliance and circuit fit

The product page describes an energy meter and includes the phrase clamp kWh energy monitor in its product presentation, and it states class 1 accuracy, with voltage on terminals 1 and 2 and the external CT secondary on terminals 3 and 4. The meter is class 1, at 1% ± 2 digits, and reads current with an external transformer.

That matters when the appliance is fixed, enclosed or supplied through a distribution board. The meter is powered from the measured AC supply. It clips onto a DIN rail and reads current through an external CT wired to terminals 3 and 4. Ask for those facts before ordering rather than treating the title as a wiring instruction.

Use a safe planning sequence

HSE guidance places the emphasis on suitable equipment, safe planning and competence. A buyer can complete the specification comparison without attempting electrical work.

  1. Record the appliance supply, expected load and measurement period from the equipment information or responsible electrician.
  2. Compare the supply with the listed AC 40.0-300.0 V and AC 0-100.0 A ranges, The stated accuracy is class 1, 1% ± 2 digits.
  3. Confirm the sensor, conductor access, wiring method, enclosure space and CAT or equivalent safety information with the manufacturer.
  4. Use a competent person for any fixed-wiring or live-circuit task and stop if the supply, equipment or instructions are uncertain.

Limits before buying

Published accuracy is class 1 (1% ± 2 digits). The colour LCD shows watts, kWh, volts, hertz, amps and power factor, refreshing about twice a second. Hold RESET for about five seconds to zero the kWh count. The meter keeps that total when the supply is off.

Read it as a DIN-rail meter for one single-phase circuit, with voltage, current, power, kWh, frequency and power factor on one screen.

This meter is worth comparing when the published ranges fit a single-phase monitoring question. Confirm the sensing and safety details first, and leave fixed-wiring work to a competent person. Read Clamp Power Monitor for a Hard-Wired Appliance for related guidance. Read CT Clamp Energy Monitor UK: Evidence Before You Buy for related guidance. Review the documented specification on the HT D52-2066 DIN-rail energy meter, AC 40-300 V, external CT product page before ordering.

Sources and safety context