How to select an
oil-immersed load break switch.

Two positions or four?

Use the required operating arrangement as your first filter. An ON/OFF requirement points to the two-position family; sectionalizing or transfer requirements call for a review of the four-position family and its connection sequence.

Record the required connections for every position. If the circuit is still being finalized, identify the open points in your inquiry rather than assuming a suitable model.

Specify the duty,
not only the voltage.

State voltage class, rated current, frequency and phase configuration. Ask for the selected model’s insulation and switching-duty data. Load switching and fault-current interruption are different functions.

Keep your transformer protection requirements in the technical brief so the switch can be reviewed in the context of the complete assembly.

Match the drawing
to the tank design.

Provide a drawing showing mounting interfaces, tank details, operating linkage, terminal locations and available space. Similar-looking products may use different dimensions or arrangements.

Request an installation drawing for the exact model revision. Do not use a family photograph as a dimensional reference.

Confirm BBM / MBB
where it applies.

For four-position requirements, describe the intended transition as well as the stable positions. Ask your system designer to confirm the required logic before selecting a part.

Send one complete brief.

• Application and transformer type.
• Electrical requirements and circuit / position diagram.
• Mechanical drawing and preferred model, if known.
• Quantity, destination, target date and sample needs.
• Requested datasheet, drawing and applicable test records.

This checklist supports a product discussion; it is not an installation or switching procedure.