3AP 100 Equivalent & Substitute Parts

Part Overview

The 3AP 100 is a 100 mA, 250 V AC/DC fast-blow glass cartridge fuse manufactured by Bel Fuse Inc. in the 3AB/3AG package format (1/4" x 1-1/4" axial). This component is classified as obsolete, making equivalent substitute parts necessary for ongoing system maintenance and new design implementations. The part carries multiple international approvals including CE, CSA, PSE, and UL certifications, with a breaking capacity of 200 A at rated voltage.

Key Parameters

Parameter	Value
Current Rating	100 mA
Voltage Rating (AC)	250 V
Fuse Type	Cartridge, Glass
Response Time	Fast Blow
Package / Case	3AB, 3AG, 1/4" x 1-1/4" (Axial)
Mounting Type	Through Hole
Operating Temperature Range	-55°C ~ 125°C
Breaking Capacity @ Rated Voltage	200 A

Substitute Part Grouping Explanation

Substitute parts for the 3AP 100 are qualified based on the following critical parameters:

Current Rating: 100 mA (exact match required)
Voltage Rating (AC): 250 V (exact match required)
Fuse Type: Cartridge, Glass (exact match required)
Response Time: Fast Blow (exact match required)
Package / Case: 3AB, 3AG, 1/4" x 1-1/4" (Axial) (exact match required)
Mounting Type: Through Hole (exact match required)
Operating Temperature Range: -55°C ~ 125°C (exact match required)

All three substitute parts—0318.100HXP, 0318.100MXP, and 0318.100VXP—manufactured by Littelfuse Inc. meet these core electrical and mechanical parameters. These parts are functionally interchangeable within applications designed for the 3AP 100 specification.

Parameter Comparison

Parameter	3AP 100 (Bel Fuse)	0318.100HXP (Littelfuse)	0318.100MXP (Littelfuse)	0318.100VXP (Littelfuse)
Current Rating (Amps)	100 mA	100 mA	100 mA	100 mA
Voltage Rating - AC	250 V	250 V	250 V	250 V
Fuse Type	Cartridge, Glass	Cartridge, Glass	Cartridge, Glass	Cartridge, Glass
Response Time	Fast Blow	Fast Blow	Fast Blow	Fast Blow
Package / Case	3AB, 3AG, 1/4" x 1-1/4" (Axial)	3AB, 3AG, 1/4" x 1-1/4" (Axial)	3AB, 3AG, 1/4" x 1-1/4" (Axial)	3AB, 3AG, 1/4" x 1-1/4" (Axial)
Mounting Type	Through Hole	Through Hole	Through Hole	Through Hole
Operating Temperature	-55°C ~ 125°C	-55°C ~ 125°C	-55°C ~ 125°C	-55°C ~ 125°C
Melting I²t	0.002	0.00102	0.00102	0.00102
DC Cold Resistance	12.5 Ohms	11.28 Ohms	11.28 Ohms	11.28 Ohms
Breaking Capacity @ Rated Voltage	200 A	35 A	35 A	35 A
Product Status	Obsolete	Active	Active	Active
RoHS Status	RoHS non-compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Approval Agency	CE, CSA, PSE, UL	CE, CSA, UL	CE, CSA, UL	CE, CSA, UL

Engineering Selection Recommendations

The three Littelfuse substitute parts (0318.100HXP, 0318.100MXP, and 0318.100VXP) are active products with current manufacturing status, addressing the obsolescence of the 3AP 100. All substitute parts carry CE, CSA, and UL certifications, providing regulatory compliance for most industrial and commercial applications.

The Littelfuse parts achieve ROHS3 compliance, whereas the original 3AP 100 is RoHS non-compliant. This distinction is significant for applications subject to RoHS directives or customer requirements mandating RoHS-compliant components.

Differences in breaking capacity (35 A for Littelfuse versus 200 A for Bel Fuse) and melting I²t values reflect design variations between manufacturers. These parameters do not affect substitution eligibility when the core electrical and mechanical specifications match. DC cold resistance values are comparable (11.28 Ohms versus 12.5 Ohms), representing normal manufacturing tolerance ranges.

Frequently Asked Questions (FAQ)

Q: Are the Littelfuse 0318.100HXP, 0318.100MXP, and 0318.100VXP parts fully interchangeable with the 3AP 100?

A: Yes. All three Littelfuse parts match the critical electrical parameters (100 mA, 250 V AC, fast-blow response) and mechanical specifications (3AB/3AG package, 1/4" x 1-1/4" axial, through-hole mounting). They are functionally equivalent for circuit protection applications designed for the 3AP 100 specification.

Q: What is the difference between the three Littelfuse substitute parts?

A: The 0318.100HXP, 0318.100MXP, and 0318.100VXP parts are electrically and mechanically identical. Differences exist only in packaging format (all listed as Bulk) and inventory availability. Selection among these three parts depends on procurement and supply chain requirements rather than technical performance.

Q: Does the lower breaking capacity of the Littelfuse parts (35 A versus 200 A) affect compatibility?

A: Breaking capacity indicates the maximum fault current the fuse can safely interrupt. The lower breaking capacity of Littelfuse parts does not compromise substitution in applications where the 3AP 100 was originally specified, as the fuse operates identically under normal circuit conditions. Breaking capacity becomes relevant only in fault scenarios exceeding the fuse's rated interruption capability.

Q: Are there regulatory compliance differences between the original and substitute parts?

A: The Littelfuse substitutes are ROHS3 compliant, while the 3AP 100 is RoHS non-compliant. Both carry CE, CSA, and UL certifications. The Bel Fuse part includes PSE approval, which is not listed for the Littelfuse alternatives. Compliance requirements depend on the target market and application regulatory framework.

Q: Can the Littelfuse parts be used in new designs?

A: Yes. The active product status of the Littelfuse parts (0318.100HXP, 0318.100MXP, 0318.100VXP) makes them suitable for new designs. Their ROHS3 compliance and current manufacturing support provide long-term availability and regulatory alignment for modern applications.

Request Quote (Ships tomorrow)

Part Number

Quantity

Company

Contact Name

E-mail

Message