S506-40-R Equivalent & Substitute Parts Reference

Part Overview

The S506-40-R is a 40 mA, 250 V AC/DC glass cartridge fuse manufactured by Eaton - Electronics Division. This slow-blow fuse is designed for applications requiring circuit protection in a 5mm x 20mm form factor with holder mounting. The part is active in production with ROHS3 compliance and multiple international approvals including UL, VDE, BSI, CCC, IMQ, and SEMKO. Equivalent and substitute parts are identified based on matching electrical ratings, mechanical dimensions, response characteristics, and approval certifications to ensure direct functional interchangeability in circuit protection applications.

Substiute Parts

S506-40-R

Eaton - Electronics DivisionIn Stock: 1137S506-40-R Datasheet

Current PartRFQ

BK/S506-40-R

Eaton - Electronics DivisionIn Stock: 886BK/S506-40-R Datasheet

DirectRFQ

0218.040MXP

Littelfuse Inc.In Stock: 13310218.040MXP Datasheet

DirectRFQ

0218.040HXP

Littelfuse Inc.In Stock: 7600218.040HXP Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the S506-40-R are classified based on strict electrical and mechanical parameter matching:

Direct Manufacturer Equivalent (Same Manufacturer): BK/S506-40-R is an Eaton - Electronics Division part number variant of the S506 series with identical electrical specifications, mechanical dimensions, and approval certifications.

Cross-Manufacturer Equivalents (Different Manufacturer): 0218.040MXP and 0218.040HXP are Littelfuse Inc. parts from the 218 series that match the following critical parameters:

• Current Rating: 40 mA
• Voltage Rating: 250 V AC
• Fuse Type: Cartridge, Glass
• Response Time: Slow Blow
• Package / Case: 5mm x 20mm
• Breaking Capacity: 35A
• Approval Agencies: CCC, CE, CSA, K-MARK, SEMKO, UL, VDE

Substitution is valid when all electrical ratings, mechanical form factor, response characteristics, and required approval certifications align with the application requirements.

Parameter Comparison

Engineering Selection Recommendations

Primary Selection (S506-40-R or BK/S506-40-R): Both Eaton parts are functionally identical and interchangeable. Selection between these two part numbers depends on inventory availability and procurement channels. Both maintain identical electrical characteristics, mechanical form factor, and approval certifications.

Cross-Manufacturer Selection (0218.040MXP or 0218.040HXP): Littelfuse 218 series parts 0218.040MXP and 0218.040HXP are parametric equivalents suitable for substitution when Eaton S506 series parts are unavailable. These parts satisfy all critical electrical and mechanical requirements:

• Matching current and voltage ratings
• Identical fuse type and response characteristics
• Identical 5mm x 20mm form factor
• Equivalent breaking capacity
• Shared approval certifications (CCC, SEMKO, UL, VDE)

Compliance Considerations: All four parts are ROHS3 compliant and REACH unaffected. Application-specific approval requirements must be verified against the target system's certification needs. The Littelfuse parts include additional certifications (CE, CSA, K-MARK) and specified operating temperature range (-55°C ~ 125°C) compared to the Eaton parts.

Resistance and Thermal Characteristics: DC cold resistance differs between manufacturers: Eaton parts measure 13.9 Ohms while Littelfuse parts measure 35.7 Ohms. Melting I²t values also differ: Eaton 0.0072 versus Littelfuse 0.00536. These differences reflect different internal construction but do not affect functional substitution for standard circuit protection applications.

Frequently Asked Questions (FAQ)

Q: Can BK/S506-40-R be used as a direct replacement for S506-40-R? A: Yes. BK/S506-40-R is an Eaton - Electronics Division part with identical electrical ratings, mechanical dimensions, response time, breaking capacity, and approval certifications. Both parts are from the S506 series and are fully interchangeable.

Q: Are Littelfuse 0218.040MXP and 0218.040HXP suitable substitutes for the Eaton S506-40-R? A: Yes. Both Littelfuse parts match the critical electrical parameters (40 mA, 250 V AC, slow-blow response), mechanical form factor (5mm x 20mm), and breaking capacity (35A). All required approval certifications are present. These parts are parametric equivalents suitable for direct substitution.

Q: What is the difference between 0218.040MXP and 0218.040HXP? A: Both parts are from the Littelfuse 218 series with identical electrical ratings, mechanical dimensions, and approval certifications. The difference in part number designation reflects internal design variants. Both are functionally equivalent for the specified application.

Q: Does the difference in DC cold resistance affect substitution? A: DC cold resistance differences (Eaton 13.9 Ohms versus Littelfuse 35.7 Ohms) reflect different internal construction but do not prevent functional substitution for standard circuit protection applications. Application-specific requirements should be verified if resistance characteristics are critical to system performance.

Q: Does the difference in melting I²t affect substitution? A: Melting I²t values differ between manufacturers (Eaton 0.0072 versus Littelfuse 0.00536). Both values fall within acceptable ranges for 40 mA slow-blow fuses. Substitution is valid for standard applications; however, systems with specific thermal response requirements should verify compatibility.

Q: Are all four parts ROHS3 compliant? A: Yes. S506-40-R, BK/S506-40-R, 0218.040MXP, and 0218.040HXP are all ROHS3 compliant and REACH unaffected.

Q: What approval certifications are common to all four parts? A: CCC, SEMKO, UL, and VDE certifications are present on all four parts. Eaton parts include BSI and IMQ. Littelfuse parts include CE, CSA, and K-MARK. Application-specific certification requirements should be verified.

Q: Do the Littelfuse parts have a specified operating temperature range? A: Yes. Littelfuse 0218.040MXP and 0218.040HXP specify -55°C ~ 125°C operating temperature range. Eaton S506-40-R and BK/S506-40-R do not specify operating temperature limits in the provided data.

Q: Can these fuses be used without a holder? A: No. All four parts require a holder for mounting. The 5mm x 20mm form factor specifies holder-based installation; direct PCB mounting is not applicable.