NH00CG40 Equivalent & Substitute Parts

Part Overview

The NH00CG40 is a 40A square fuse rated for 500 VAC and 440 VDC operation, manufactured by Littelfuse Inc. and classified as NH series. This component is designed for motor protection applications and features fast-blow response with an indicating function. The part is currently listed as obsolete, making identification of suitable substitute components necessary for ongoing system maintenance and component procurement.

Substiute Parts

NH00CG40

Littelfuse Inc.In Stock: 1056NH00CG40 Datasheet

Current PartRFQ

40NHG000B

Eaton - Bussmann Electrical DivisionIn Stock: 81040NHG000B Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the NH00CG40 is based on the following critical parameters that must remain constant or compatible:

• Current Rating: 40A (exact match required)
• Voltage Rating - AC: 500 VAC (exact match required)
• Fuse Type: Square (exact match required)
• Class: NH (exact match required)
• Response Time: Fast Blow (exact match required)
• Mounting Type: Requires Holder (exact match required)
• Approval Agency: VDE certification (maintained)

The substitute part 40NHG000B meets these core criteria. The primary difference is the DC voltage rating, which is reduced from 440 VDC to 250 VDC. This represents a constraint on the substitute's application scope rather than a functional incompatibility, as the substitute remains suitable for applications operating at or below 250 VDC.

Parameter Comparison

Engineering Selection Recommendations

The 40NHG000B from Eaton - Bussmann Electrical Division is the identified substitute for the obsolete NH00CG40. Selection of this substitute is supported by the following factors:

• Active product status ensures ongoing availability and supply chain continuity
• Identical current rating (40A) and AC voltage rating (500 VAC) maintain primary circuit protection characteristics
• Matching NH class, fast-blow response, and VDE approval preserve functional equivalence for motor protection applications
• RoHS compliance of the substitute aligns with modern regulatory requirements
• DC voltage rating reduction from 440 VDC to 250 VDC requires verification that the application does not exceed 250 VDC operation

Component selection must confirm that the application's maximum DC operating voltage does not exceed 250 VDC. For applications requiring 440 VDC DC rating, alternative substitutes outside the provided dataset must be evaluated.

Frequently Asked Questions (FAQ)

Q: Can the 40NHG000B be used as a direct replacement for the NH00CG40?

A: The 40NHG000B is functionally equivalent for applications operating at or below 250 VDC. The primary difference is the reduced DC voltage rating. If your application operates exclusively at AC 500 VAC or at DC voltages not exceeding 250 VDC, the substitute is suitable. Applications requiring 440 VDC operation require alternative components.

Q: What are the critical parameters that must match between the original and substitute?

A: Current rating (40A), AC voltage rating (500 VAC), fuse type (square), class (NH), response time (fast blow), and mounting type (requires holder) must remain identical. The DC voltage rating is the only parameter that differs between these two parts.

Q: Does the 40NHG000B require the same holder as the NH00CG40?

A: Both parts are square fuses requiring a holder and are classified as NH series. Physical dimensions differ slightly, so holder compatibility must be confirmed with the specific holder model used in your application.

Q: What is the significance of the RoHS compliance difference?

A: The 40NHG000B is RoHS compliant, while the NH00CG40 is not. For new designs or systems subject to RoHS regulations, the substitute provides regulatory alignment. Existing systems using the non-compliant original part may continue operation without modification.

Q: Are there any applications where the NH00CG40 cannot be substituted with the 40NHG000B?

A: Applications requiring DC voltage operation above 250 VDC cannot use the 40NHG000B as a substitute. The original part's 440 VDC rating is necessary for such applications.