NH00G125 Square Fuse 125A 500VAC/440VDC Equivalent & Substitute Parts

Part Overview

The NH00G125 is a square fuse rated for 125A at 500VAC/440VDC, manufactured by Littelfuse Inc. in the NH class. This component is designed for motor protection applications and features fast-blow response with an indicating function. The part is currently obsolete, making identification of compatible substitutes essential for maintenance, repair, and replacement applications in industrial and electrical systems.

Substiute Parts

NH00G125

Littelfuse Inc.In Stock: 839NH00G125 Datasheet

Current PartRFQ

125NHG00B

Eaton - Bussmann Electrical DivisionIn Stock: 990125NHG00B Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

The 125NHG00B from Eaton - Bussmann Electrical Division qualifies as a direct substitute based on the following critical parameters:

• Current Rating: Both parts are rated 125A
• Voltage Rating - AC: Both parts are rated 500VAC
• Fuse Type: Both are square fuses
• Response Time: Both feature fast-blow response
• Class: Both are NH class
• Mounting Type: Both require a holder
• Package / Case: Both use rectangular blade configuration
• Approval Agency: Both carry VDE certification

The primary difference is the DC voltage rating: the NH00G125 is rated 440VDC, while the 125NHG00B is rated 250VDC. This difference must be evaluated against the actual system requirements before substitution.

Parameter Comparison

Engineering Selection Recommendations

The 125NHG00B is an active product with current manufacturing support and ROHS3 compliance, making it suitable for new installations and systems requiring modern regulatory adherence. The NH00G125, being obsolete, should be replaced with the 125NHG00B in applications where the 250VDC rating is sufficient.

For systems operating at DC voltages exceeding 250VDC, the reduced DC voltage rating of the 125NHG00B must be considered against system requirements. Both parts carry VDE certification and maintain identical AC voltage ratings, current ratings, and mechanical form factors, ensuring physical and electrical compatibility within the specified DC voltage envelope.

Frequently Asked Questions (FAQ)

Q: Can the 125NHG00B directly replace the NH00G125 in all applications?

A: Physical and electrical compatibility is confirmed for AC applications and DC systems operating at or below 250VDC. Systems requiring the full 440VDC DC rating of the original part require verification that the 125NHG00B's 250VDC rating meets operational requirements.

Q: What is the significance of the NH class designation?

A: NH class fuses are industrial-grade, high-breaking-capacity fuses designed for motor protection and industrial electrical systems. Both parts conform to this class standard, ensuring equivalent performance characteristics within their respective voltage ratings.

Q: Are there mechanical compatibility concerns between these parts?

A: Both parts use rectangular blade packaging and require a holder for mounting. Physical dimensions differ slightly, but both conform to NH class form factors. Verify holder compatibility with the specific installation.

Q: What compliance advantages does the 125NHG00B offer?

A: The 125NHG00B carries ROHS3 compliance and CE certification in addition to VDE approval, making it suitable for applications in regions with modern environmental and safety regulations. The NH00G125 is RoHS non-compliant.

Q: How do the breaking capacities compare?

A: The NH00G125 specifies 120kA AC and 25kA DC breaking capacity. The 125NHG00B specifies 120kA breaking capacity. Both provide equivalent performance for industrial motor protection applications within their respective voltage ratings.