Leviton MS403-DS 3-Pole 600-Volt 40-Amp 3-Phase Industrial Grade Toggle Motor Starting Switch
The Leviton MS403-DS is an industrial grade toggle AC motor starting switch built for reliable manual control of demanding 3-phase motor loads. Configured as a 3-Pole switch and rated 600-Volt and 40-Amp, this unit is engineered for 3-Phase circuits found in commercial and industrial power distribution systems. Its heavy-duty toggle actuator delivers simple, dependable on/off motor switching where consistent performance under load is critical. Industrial grade construction ensures this switch stands up to the rigors of continuous use in demanding electrical environments.
Key Features
- Pole Configuration: 3-Pole design supports full 3-phase motor circuit switching.
- Voltage Rating: 600-Volt rating for use across industrial and commercial power systems.
- Amperage Rating: 40-Amp rating suited for motor starting and load-switching applications.
- Phase Configuration: 3-Phase compatibility for industrial motor and equipment circuits.
- Industrial Grade Construction: Built to industrial grade standards for long-term durability in demanding installations.
- Toggle Operation: Toggle-style actuator provides quick, positive, dependable manual switching action.
- AC Motor Starting Function: Purpose-built for manual AC motor starting and disconnecting duties.
Technical Specifications
- Poles: 3-Pole
- Voltage: 600-Volt
- Amperage: 40-Amp
- Phase: 3-Phase
- Grade: Industrial Grade
- Switch Type: Toggle AC Motor Starting Switch
Typical Applications
- Industrial Motor Control Panels
- Commercial HVAC and Pump Motor Circuits
- 3-Phase Industrial Equipment Installations
- Manufacturing and Processing Facility Wiring
- Renovation and New Construction Motor Control Upgrades
- Manual Disconnect Switching for 3-Phase Motor Loads
Why Leviton?
Leviton engineers the MS403-DS to industrial grade standards, delivering the durability and dependable switching performance professionals require for 3-phase motor control in demanding electrical environments. With its rugged toggle actuator and 3-Pole, 600-Volt, 40-Amp rating, this switch is built to perform reliably in industrial and commercial power systems. Specify Leviton for code-compliant, professional-grade motor control and switching solutions on your next installation.
Manufacturer Resources
Technical Information
Product Specs
- Product Type:
- Motor Starting Switch
- Connection Type:
- Toggle
- Amperage Rating:
- 40A
- Voltage Rating:
- 600V
- Poles:
- 3
- Grade:
- Industrial
- Product Color:
- Black
- Department:
- Electrical
- Product Group:
- Motor Control & Automation
- Product Subgroup:
- Motor Starters & Contactors
Leviton MS403-DS – Frequently Asked Questions
1) Can the Leviton MS403-DS motor starting switch be used as the disconnect for a 3-phase motor on a 480V system?
The MS403-DS is rated 600V, so a 480V three-phase circuit is inside its rating. It's a 3-pole switch, meaning it breaks all three ungrounded conductors of the motor circuit at once, which is what a manual disconnecting means for a three-phase load has to do. Amperage rating is 40A, so the motor's full load current plus whatever your design allows for the switch has to sit at or below that.
2) Does the Leviton MS403-DS provide motor overload protection, or do I still need a starter?
It's a manually operated toggle switch, not a magnetic starter and not an overload relay. The MS403-DS makes and breaks the motor circuit by hand; it does not sense motor current or drop out on an overload, and it will not start or stop the motor from a remote pushbutton or control circuit. If the motor needs running overload protection or remote/automatic control, the switch goes in the circuit alongside that equipment rather than replacing it.
3) Will a 40-amp motor switch handle a 10 HP or 15 HP three-phase motor?
Size it by the motor's full load amps against the switch's 40A rating, not by horsepower alone. At 40A and 600V, three-pole, the MS403-DS covers the common range of mid-size commercial motors, but a 15 HP motor at 208V draws considerably more current than the same motor at 480V. Pull the FLA off the motor nameplate and confirm it, and everything the circuit design requires above it, fits within 40A before you specify this switch.
4) Can I use a Leviton MS403-DS three-pole motor switch on a single-phase 240V motor?
You can, electrically, by using two of the three poles, but you're buying a pole you won't use. The MS403-DS is a 3-pole device built for three-phase circuits. For a single-phase 240V motor a two-pole manual motor switch of the same 600V class is the closer match. Where the MS403-DS earns its place is a three-wire, three-phase feed where all three legs have to open together.
5) What does "industrial grade" mean on a Leviton motor starting switch versus a standard wiring device?
Industrial grade is Leviton's construction tier above residential and commercial grade wiring devices, built for repeated switching duty in plants and mechanical rooms rather than occasional use. On the MS403-DS that pairs with a 600V, 40A, three-pole rating, which is a distribution-class rating, not a general-purpose snap switch rating. A standard toggle wall switch is nowhere near this duty and must not be substituted on a motor circuit.
6) Is a manual toggle motor switch the right choice, or should I be specifying a magnetic starter?
Pick the toggle switch when an operator throws it by hand at the machine and nothing else needs to control the motor: a pump, a fan, a piece of shop equipment where local on/off is the whole requirement. The MS403-DS is that device, three-pole at 600V and 40A. A magnetic starter is the answer when you need remote pushbutton control, control-circuit interlocks, or automatic restart behavior after a power loss, because a manual toggle stays wherever the operator left it when power returns.
7) What is the Leviton part number for a 3-pole 40 amp 600 volt manual motor switch?
MS403-DS is the Leviton catalog number for the industrial grade three-pole, 600V, 40A toggle motor starting switch. That single part number covers the whole device, and it's what to put on a purchase order or a submittal for this configuration.
8) I'm replacing an existing manual motor switch in a control panel. Will the MS403-DS drop into the same opening?
Match it on ratings first: three poles, 600V class, 40A. If the switch coming out is a 40A three-pole manual motor switch, the MS403-DS is the same electrical configuration. Mounting is a separate check, though. Confirm the mounting pattern and enclosure opening of the unit you're pulling against the MS403-DS installation sheet before you commit, since manual motor switch bodies are not standardized the way a duplex receptacle is.
9) What color is the Leviton MS403-DS toggle switch, and does it come in other colors?
Black is the only finish the MS403-DS is built in. The MS403-DS is a single configuration, so there's no color or amperage choice to make on the order; the model number itself is the whole specification.
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Does the Leviton MS403-DS come with a warranty?
Absolutely. The Leviton MS403-DS is backed by a manufacturer’s warranty.
For full warranty terms, check the product documentation or Contact Us.
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