Littelfuse 0218.040MXP Glass Cartridge Fuse Equivalent & Substitute Parts

Part Overview

The Littelfuse 0218.040MXP is an active-status glass cartridge fuse rated at 40 mA, 250 V AC/DC with slow-blow response characteristics. This component is designed for circuit protection in applications requiring a 5mm x 20mm form factor with holder-based mounting. Substitute parts are identified when equivalent electrical and mechanical parameters are maintained across the same fuse category, enabling component interchangeability for procurement flexibility and supply chain continuity.

Substiute Parts

0218.040MXP

Littelfuse Inc.In Stock: 13310218.040MXP Datasheet

Current PartRFQ

0218.040HXP

Littelfuse Inc.In Stock: 7600218.040HXP Datasheet

DirectRFQ

BK/S506-40-R

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

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the 0218.040MXP is determined by strict equivalence across the following critical parameters:

• Current Rating: 40 mA (exact match required)
• Voltage Rating (AC): 250 V (exact match required)
• Fuse Type: Cartridge, Glass (exact match required)
• Response Time: Slow Blow (exact match required)
• Package / Case: 5mm x 20mm (exact match required)
• Mounting Type: Requires Holder (exact match required)
• Breaking Capacity @ Rated Voltage: 35 A (exact match required)

All identified substitute parts meet these criteria. Variations in secondary parameters such as DC Cold Resistance, Melting I²t, and approval agency certifications do not preclude substitution when primary electrical and mechanical specifications are identical.

Parameter Comparison

Engineering Selection Recommendations

All three parts—0218.040MXP, 0218.040HXP, and BK/S506-40-R—are active-status components with full RoHS3 compliance and REACH unaffected status. Selection between Littelfuse 0218.040MXP and 0218.040HXP is interchangeable based on identical electrical specifications and identical approval certifications (CCC, CE, CSA, K-MARK, SEMKO, UL, VDE).

The Eaton BK/S506-40-R substitute maintains all critical electrical and mechanical parameters. Approval certifications differ (BSI, CCC, IMQ, SEMKO, UL, VDE versus Littelfuse certifications), and secondary parameters including DC Cold Resistance (13.9 Ohms versus 35.7 Ohms) and Melting I²t (0.0072 versus 0.00536) vary. These differences do not affect substitution eligibility when primary specifications are matched.

Selection should be based on supply availability, approval agency requirements for the end application, and inventory status.

Frequently Asked Questions (FAQ)

Q: Can 0218.040HXP directly replace 0218.040MXP?

A: Yes. Both parts are manufactured by Littelfuse, share identical current rating (40 mA), voltage rating (250 V), fuse type (Cartridge, Glass), response time (Slow Blow), package dimensions (5mm x 20mm), and approval certifications. They are direct equivalents.

Q: Is the Eaton BK/S506-40-R compatible with applications designed for 0218.040MXP?

A: Yes, from an electrical and mechanical standpoint. The BK/S506-40-R maintains the same current rating, voltage rating, fuse type, response time, and package dimensions. Approval agency certifications differ; verify that BSI, CCC, IMQ, SEMKO, UL, and VDE certifications satisfy application requirements.

Q: What is the significance of the difference in DC Cold Resistance between parts?

A: DC Cold Resistance (35.7 Ohms for Littelfuse parts versus 13.9 Ohms for Eaton BK/S506-40-R) is a secondary parameter that does not affect substitution eligibility when primary electrical specifications (current, voltage, response time) are identical. This parameter reflects internal fuse element design and does not impact circuit protection performance at rated specifications.

Q: Do all substitute parts require the same holder?

A: Yes. All parts share the 5mm x 20mm package dimension and require holder-based mounting. Existing holders designed for 0218.040MXP are compatible with 0218.040HXP and BK/S506-40-R.

Q: Are there any temperature rating differences between substitutes?

A: Littelfuse parts specify -55°C ~ 125°C operating temperature range. Eaton BK/S506-40-R does not specify an operating temperature range in the provided data. For applications with defined temperature requirements, verify Eaton specifications independently or select Littelfuse parts.