3JQ 4-R Glass Cartridge Fuse Equivalent & Substitute Parts

Part Overview

The 3JQ 4-R is a 4A fast-blow glass cartridge fuse manufactured by Bel Fuse Inc., rated for 350V AC and 140V DC operation. This through-hole component is designed for circuit protection in industrial and commercial applications requiring reliable overcurrent interruption. The part maintains active product status with 1141 units in current inventory. Substitute parts are identified to provide alternative sourcing options when the primary part is unavailable or when supply chain optimization is required.

Substiute Parts

3JQ 4-R

Bel Fuse Inc.In Stock: 12163JQ 4-R Datasheet

Current PartRFQ

0208004.MXEP

LittelfuseIn Stock: 18240208004.MXEP Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the 3JQ 4-R are identified based on the following critical parameters that determine functional equivalence:

• Current Rating: 4 A (exact match required)
• Voltage Rating - AC: 350 V (exact match required)
• Package / Case: 2AG, 5mm x 15mm (Axial) (exact match required)
• Fuse Type: Cartridge, Glass (exact match required)
• Response Time: Fast Blow (exact match required)
• Mounting Type: Through Hole (exact match required)

The substitute part 0208004.MXEP manufactured by Littelfuse meets all critical electrical and mechanical parameters for direct substitution in 350V AC applications. Minor variations in physical dimensions (0.185" Dia x 0.570" L versus 0.217" Dia x 0.591" L) and DC voltage rating remain within acceptable tolerance for through-hole mounting compatibility. The melting I²t value of 9.4 for the substitute is lower than the primary part's 12, indicating slightly faster thermal response characteristics while maintaining the fast-blow classification.

Parameter Comparison

Engineering Selection Recommendations

Both the 3JQ 4-R and 0208004.MXEP maintain active product status with current manufacturing support. The primary part carries CSA certification in addition to CE, cURus, and PSE approvals. The substitute part holds CE, cURus, and PSE certifications. Selection between these components should be based on specific certification requirements for the target application. Both parts are ROHS3 compliant and suitable for industrial circuit protection applications operating within the -55°C to 125°C temperature range. The substitute part's lower melting I²t value (9.4 versus 12) indicates marginally faster thermal response, which may be advantageous in applications requiring tighter protection margins.

Frequently Asked Questions (FAQ)

Q: Can the 0208004.MXEP directly replace the 3JQ 4-R in all applications?

A: The 0208004.MXEP is electrically and mechanically compatible for 350V AC applications. Both components share identical current ratings, voltage ratings for AC operation, package specifications, and response characteristics. Physical dimension variations are minor and do not affect through-hole mounting compatibility. Applications requiring CSA certification should retain the primary part.

Q: What is the significance of the different melting I²t values?

A: The melting I²t parameter defines the thermal energy required to melt the fuse element. The 3JQ 4-R has a melting I²t of 12, while the 0208004.MXEP has 9.4. Both maintain fast-blow classification. The lower value in the substitute indicates slightly faster thermal response to overcurrent conditions.

Q: Are there differences in DC voltage ratings between these parts?

A: The 3JQ 4-R is rated for 140V DC operation. The 0208004.MXEP specification does not explicitly state a DC voltage rating. For applications requiring DC operation, the primary part should be used unless the substitute's DC capability is independently verified.

Q: How do the DC cold resistance values affect circuit performance?

A: The 3JQ 4-R has a DC cold resistance of 0.019 Ohms, while the 0208004.MXEP measures 0.024 Ohms. This 0.005 Ohm difference is negligible in most circuit applications and does not affect functional equivalence for standard protection applications.

Q: What certifications should I consider for my application?

A: The 3JQ 4-R carries CE, CSA, cURus, and PSE approvals. The 0208004.MXEP carries CE, cURus, and PSE approvals. If your application requires CSA certification, the primary part is required. Both parts meet international safety standards for industrial use.