ABB OT Switch-Disconnectors

An OT switch-disconnector is used to make and break suitable load circuits and provide an isolating function under its specified conditions. Typical applications include distribution-board main switching and equipment isolation. It does not provide automatic overload or short-circuit tripping; coordinate it with the specified upstream protective device and follow installation and isolation procedures.

Product Range & Installation

ABB’s manual switch-disconnector catalogue covers smaller OT16…160 and larger OT160…4000 offerings with different frames and operating arrangements. These catalogue groupings do not mean every frame has the same ratings, poles, mounting options or approvals. The existing list includes several contact and pole arrangements; confirm the complete type rather than interpreting every suffix without its drawing.

Select the required poles and neutral arrangement, front or side operation, direct handle or external door-operated handle, and base or door mounting where supported. Confirm enclosure depth, shaft length, handle position, locking requirements, conductor size and terminal space. Mounting and handle choices are product-specific; use the assembly drawing and installation instructions.

Load Ratings & IEC / UL Boundaries

ABB’s IEC technical data uses IEC/EN 60947-3. Check rated operational current Ie at the actual operational voltage and utilization category, not only a thermal current Ith or frame size. AC-22 duty concerns mixed resistive and inductive loads; AC-23 concerns motor or other highly inductive loads. Ratings at one voltage or duty must not be transferred to another.

ABB also documents UL 98 or UL 508 and CSA versions for applicable products. Their ampere, horsepower, installation and protection requirements must be read from the exact regional product documentation; an IEC designation is not proof of a UL approval. AC ratings must not be used as DC ratings. Dedicated DC and non-load-break versions require their own pole connection and duty information.

Short-circuit withstand or conditional ratings are not a circuit-breaker interrupting rating. Check ABB’s specified protective-device combination and fault level for the exact switch, voltage and assembly.

Match the Body & Accessories

Handles, shafts, auxiliary contacts, additional poles, terminal shrouds and connection accessories must match the switch frame and operating arrangement. ABB notes that listed accessories are not automatically included in an order. Confirm what is supplied with the exact body code, then identify the required accessories separately; do not assume a handle or shaft in an illustration is included.

Confirming an OT Selection

Provide supply voltage/frequency, AC or DC duty, load type, required current and utilization category, pole/neutral arrangement and local standard. Confirm manual operation, mounting method, handle/shaft arrangement, enclosure depth, cable sizes and auxiliary-contact requirements. Include the upstream protective device and prospective short-circuit level for coordination checks. For an existing installation, send the full nameplate and photos of the body and operating mechanism.

Related pages: Switch Disconnectors & Fuses and Contact. A motor-operated or change-over requirement needs its own product selection; this page does not establish interchangeability.

ABB references: Manual switch-disconnectors overview; OT catalogue: ratings, mounting and accessories; Switch utilization categories.