QOB3125VH

What type of circuit breaker is this?

The QOB3125VH is a three-pole miniature circuit breaker in the QO range. It has a 125 A current rating and a bolt-on mounting arrangement for use in compatible electrical distribution equipment.

What are the rated operating voltages?

The datasheet lists voltage ratings of 120 V AC, 120/240 V AC and 240 V AC. The electrical system voltage and configuration must match the breaker's ratings.

Can this breaker be used on a 400 V three-phase supply in Thailand?

No. The listed AC voltage ratings extend only to 240 V, so this breaker is not suitable for a 400 V three-phase circuit. Having three poles does not mean it is rated for every three-phase supply voltage.

What is the short-circuit interrupting rating?

The breaker has a listed interrupting rating of 22 kA at its specified AC voltages. This describes its fault-current interruption capability and is separate from its 125 A current rating.

Is this breaker suitable for a 50 Hz electrical system?

The datasheet specifies interrupting ratings at both 50 Hz and 60 Hz. It can therefore be considered for a 50 Hz installation where the voltage, panel compatibility and other application requirements match its specifications.

How is the breaker mounted?

This model uses bolt-on mounting rather than a plug-in connection. The receiving panel must explicitly accommodate this breaker type; matching the current rating alone does not establish compatibility.

How many panel spaces does it require?

The QOB3125VH requires six panel spaces, despite having three poles. This space requirement should be checked when assessing whether it will fit an existing distribution panel.

Which conductor sizes and materials can the terminals accommodate?

The listed conductor range is AWG 4 to 300 kcmil for copper or aluminium conductors. Connections use box lugs. Conductor selection must also account for the installation requirements and the terminal markings.

What are the physical dimensions?

The listed dimensions are approximately 145 mm high, 114 mm wide and 124 mm deep. These measurements describe the breaker itself; panel fit also depends on the mounting arrangement and connection clearances.

What ambient temperature is specified for the breaker?

The datasheet lists an ambient rating of 40 °C. For installations in Thailand, enclosure temperature should be assessed rather than relying solely on the surrounding room temperature.

Which certifications are listed?

The product datasheet lists UL Listed and CSA certifications. These should be considered alongside the applicable local requirements and the approval of the complete electrical assembly.