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Eaton Mechanical Interlock Contactor Accessory, M Frame
The Eaton Mechanical Interlock Contactor Accessory is engineered for two horizontally mounted contactors with an AC or DC operated magnet system, giving panel builders a reliable way to guarantee that two contactors can never close at the same time. Sized for the M frame contactor family, this accessory measures 2.75 in wide, 3 in deep, and 2.5 in high, making it a compact addition to control panels and motor control centers. Built by Eaton, it is a purpose-made accessory type rather than a standalone switching device, and it is backed by a 1 year manufacturer warranty for dependable long-term performance in demanding electrical control applications.
Key Features
- Frame Size: Designed for M frame contactors, ensuring correct fit and function within the Eaton contactor lineup.
- Compact Dimensions: Product width of 2.75 in, depth of 3 in, and height of 2.5 in for efficient use of panel space.
- Mechanical Interlock Function: Physically prevents two horizontally mounted contactors from closing simultaneously, a critical safeguard for reversing and transfer applications.
- AC or DC Compatible: Suitable for contactors with an AC or DC operated magnet system, adding flexibility across control schemes.
- Engineered Lifespan: Eaton rates B-G frame interlocks for 2.5x10^6 operations at 0mm distance between contactors, and L-N frame interlocks for 5x10^6 operations at 15mm distance between contactors, reflecting the durability engineered into the mechanical interlock family.
- Accessory Type: Classified as a contactor accessory, intended to be paired with compatible Eaton contactors rather than used independently.
- Warranty: Backed by a 1 year Eaton warranty for added confidence in commercial and industrial installations.
Technical Specifications
- Size: M frame
- Type: Accessory
- Product Width: 2.75 in
- Product Length/Depth: 3 in
- Product Height: 2.5 in
- Warranty: 1 year
- Certifications: Not Applicable
Typical Applications
- Reversing Motor Control Circuits
- Transfer Switching Between Two Contactors
- Motor Control Centers and Control Panels
- Commercial and Industrial Electrical Installations
- Panelboard and Motor Starter Assemblies
Why Eaton?
Eaton engineers its mechanical interlock accessories with defined operational lifespans, precise mounting distances, and frame-specific fitment so electricians and panel builders can trust consistent, code-compliant performance. With compact dimensions, AC/DC magnet system compatibility, and a 1 year warranty, this M frame mechanical interlock helps ensure that critical reversing and transfer applications operate safely and reliably over the long term.
Manufacturer Resources
Product Specs
- Product Width:
- 2.75 in
- Warranty:
- 1 year
- Product Size:
- M frame
- Product Length/Depth:
- 3 in
- Product Height:
- 2.5 in
- Product Type:
- Mechanical Interlock
- Certifications:
- Not Applicable
- Department:
- Electrical
- Product Group:
- Motor Control & Automation
- Product Subgroup:
- Motor Starters & Contactors
Eaton MSAA208289 – Frequently Asked Questions
1) What does the Eaton MSAA208289 mechanical interlock actually do in a motor control panel?
It is a mechanical accessory that physically blocks two contactors from closing at the same time. Bolted between a pair of horizontally mounted M frame contactors, it makes an electrical reversing or transfer scheme fail safe on the mechanics rather than relying only on interlocking auxiliary contacts. Typical uses are reversing motor starters and transfer switching between two contactors in motor control centers and control panels. It does no switching itself, so it is always ordered alongside the contactors.
2) Will this Eaton interlock fit my contactors, or is it frame specific?
Frame specific. The MSAA208289 is built for the M frame contactor family, and Eaton sizes interlocks per frame, so it will not mount on a B, G, L or N frame contactor. Check the frame designation on the contactor label before ordering, not just the amp rating.
3) Do the two contactors have to be mounted side by side for this interlock to work?
Yes. This interlock is made for two horizontally mounted contactors sitting adjacent to each other. Stacked or separated mounting arrangements will not accept it, so lay the panel out with the pair side by side before you buy.
4) Does this interlock work with DC coil contactors or only AC?
Both. The M frame mechanical interlock suits contactors with an AC or DC operated magnet system, so it works across either control scheme without a different part number.
5) How much panel space does the Eaton M frame mechanical interlock take up?
It measures 2.75 in wide, 3 in deep and 2.5 in high. That is the footprint to allow between and around the contactor pair when you are laying out a crowded motor control center backpan.
6) Can I use a mechanical interlock instead of wiring electrical interlocks between the contactors?
Treat it as an addition, not a replacement. The mechanical interlock is the physical backstop that guarantees both contactors cannot be closed together even if control wiring or an auxiliary contact fails. Most reversing and transfer designs use the mechanical interlock with the control circuit interlocking, not one in place of the other.
7) Is the MSAA208289 a switching device I can order on its own?
No. It is a contactor accessory with no contacts or coil of its own. On its own it does nothing; it only functions once fitted between two compatible M frame Eaton contactors, which have to be ordered separately.
8) Does the Eaton M frame mechanical interlock carry a UL or CSA listing?
The MSAA208289 is supplied as a mechanical contactor accessory with certifications listed as not applicable. Approval for the assembly comes from the contactors and the panel build itself, so specify the contactor ratings to meet your job's listing requirements.
How fast can I get the Eaton MSAA208289 delivered?
Most orders ship the same day from our distribution partners, with quick delivery throughout the
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Can I return it if it doesn’t work for me?
Yes—ZenSupply offers a hassle-free return policy. If the product isn’t the right fit,
reach out to our support team for a return authorization or setup a return by following our return instructions.
Does the Eaton MSAA208289 come with a warranty?
Absolutely. The Eaton MSAA208289 is backed by a manufacturer’s warranty.
For full warranty terms, check the product documentation or Contact Us.
How do I get technical support or installation help for the Eaton MSAA208289?
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