Why setup matters

A power logger usually runs unattended for days. If a clamp is reversed or the interval is wrong, you only find out when you download the data, and by then the site visit is over. Working through a short checklist before you close the panel door saves a repeat trip.

1. Choose the right current probe

Match the probe to the cable and the current. Flexible iFlex probes wrap around large or bunched conductors in tight switchboards. Rigid clamps suit smaller cables and give better accuracy at low currents. Check the expected load first: a probe sized far above the actual current loses resolution on light loads.

2. Install the probes in the right direction

Each probe has an arrow that should point towards the load. A reversed probe shows negative power on that phase and corrupts the totals. Keep the probe closed fully and centred on the conductor.

3. Match phases and choose the wiring configuration

Connect voltage leads and current probes phase for phase: L1 with L1, L2 with L2, L3 with L3. Then set the correct topology on the logger, for example 3-phase wye (3P4W) for most Malaysian low-voltage boards. Use the logger's phasor and verification screen to confirm rotation and polarity before you start.

4. Pick a logging interval that fits the study

Shorter intervals capture more detail but fill memory faster. For tariff and maximum demand analysis, record at an interval that divides cleanly into TNB's 30-minute demand period, such as 1, 5 or 10 minutes. For fault finding, use a shorter interval over a shorter period.

5. Power the logger for the full duration

Don't rely on the internal battery for multi-day studies. Power the logger from the measured line or a stable supply so a battery running flat doesn't cut the recording short.

6. Start the session, then confirm it is running

It sounds obvious, but forgetting to start, or stopping by accident while closing up, is one of the most common failures. After starting, check the logging indicator and the remaining memory and duration on screen.

7. Note the details you'll need later

Record the site, board name, start time, CT sizes and any loads that were off during the study. Notes like these make the data far easier to interpret when you write the report.

Rent a logger set up for your job

HXW rents the Fluke 1738 with clamps, software and a calibration certificate. Tell us the board and the purpose of the study, and we can pre-configure the logging settings before dispatch.