A2.57 SQUARE D Thermal Overload Unit Fnob

Review SQUARE D Squarea2.57 Thermal Overload Unit Fnob

The Square A2.57 Thermal Overload Unit FNOB, manufactured by Square D, is a crucial safety component designed to protect electrical circuits from overheating and potential fires. This thermal overload device is specifically designed for industrial and commercial applications where electrical loads can exceed normal operating temperatures.

The Square A2.57 Thermal Overload Unit FNOB is a single-pole, 2-wire, 50 ampere device. It is designed with a thermal element that senses the temperature of the electrical current flowing through it. If the temperature rises above a safe level, the thermal element causes the contacts to open, breaking the circuit and preventing further current flow. This action helps to prevent damage to connected equipment and potential electrical fires.

The Square A2.57 Thermal Overload Unit FNOB is housed in a rugged, die-cast aluminum enclosure that is both corrosion-resistant and suitable for use in harsh environments. The device is also UL listed, ensuring that it meets the highest safety standards set by Underwriters Laboratories.

The FNOB (Fast Non-Time Delay) designation of this thermal overload device indicates that it does not have a time delay feature. Instead, it opens immediately when the temperature threshold is reached, making it an excellent choice for applications where rapid response is critical.

The Square A2.57 Thermal Overload Unit FNOB is easy to install, with clear markings on the terminal screws indicating the proper wiring configuration. It is also suitable for use with Square D QO, QO1, and Homeline circuit breakers.

Overall, the Square A2.57 Thermal Overload Unit FNOB is an essential safety device for industrial and commercial electrical systems. Its fast response time, rugged construction, and UL listing make it a reliable and effective solution for preventing electrical overheating and potential fires.

The Square A2.57 Thermal Overload Unit FNOB is a protective device designed to prevent electrical overheating and potential fires. Here are some potential pros and cons of purchasing this unit:

1. Safety: The primary benefit of a thermal overload unit is safety. By monitoring the temperature of electrical circuits and interrupting the power supply when necessary, it can help prevent electrical overheating and potential fires.

2. Compliance: In some industries or applications, thermal overload protection may be required by regulations or codes. By installing a thermal overload unit, you can ensure compliance with these requirements.

3. Peace of mind: Having thermal overload protection in place can provide peace of mind, knowing that your electrical system is being monitored for potential issues.

1. Cost: Thermal overload units, especially industrial-grade models like the Square A2.57, can be expensive. The cost of the unit itself, as well as the cost of installation and maintenance, should be considered.

2. Complexity: Installing and configuring a thermal overload unit can be a complex process, requiring specialized knowledge and tools. Hiring a professional electrician to install and configure the unit may add to the cost.

3. False alarms: Thermal overload units can sometimes trigger false alarms, interrupting power supply even when there is no actual overheating issue. This can be frustrating and may require troubleshooting to identify and resolve the issue.

The Square A2.57 Thermal Overload Unit FNOB can provide important safety benefits and help ensure compliance with regulations or codes. However, it comes with some costs and complexities. The decision to purchase this unit ultimately depends on the specific requirements and priorities of your application. If safety and compliance are top priorities, and the cost and complexity are acceptable, then purchasing the Square A2.57 Thermal Overload Unit FNOB may be a good investment. If cost or complexity are major concerns, then alternative solutions, such as regular temperature monitoring or preventative maintenance, may be worth considering.

Details:

Squarea2.57 thermal overload unit thermal overload unit for a series contractors and motor starters, rated 2.05-2.46a, class 20 standard trip, melting alloy sensing method, plug-in mounting.specifications series. The product must be the original item shipped, with matching serial numbers if applicable. Most items are in stock when they listed. Mounting type: plug-in.

A new, unused item with no signs of wear. The item has its original packaging but it is not sealed. Sensing method: melting alloy. Type: thermal unit.

Trip type: standard. Manufacturer part number: A2.57. 2-year MRI shield protection plan included. Squarea2.57 thermal overload unit manufactured by Square.

Special instructions.

specifications genpurrelays:

• brand: Square D
• mpn: A2.57
• part type: Unit

shipping genpurrelays:

• class: standard, one-day
• transit: 2-6 days
• service: ups ground, ups next day air
• carrier: ups
• type: calculated

returns genpurrelays:

• method: money back
• paid by: buyer
• time: 30 days
• policy: returns accepted

payments genpurrelays:

• other
• wallet: apple-pay
• credit card: mastercard

seller genpurrelays:

• # reviews: 19495
• rating: 99.6%
• city: mount sterling, kentucky

offer genpurrelays:

• started: january 8, 2026
• prices: $10.00–$175.51
• item condition:
  • New
  • New – Open box
• sold #: 8
• options: ship-to-home
• in stock #: 5
• availability: in stock
• best offers: true

general genpurrelays:

• category: Business & Industrial > Electrical Equipment Supplies > General Purpose Relays