SPNH350.X3LDLMS

Part Overview

The SPNH350.X3LDLMS is a 350A 1.5 kVDC photovoltaic fuse with rectangular bolt mount configuration manufactured by Littelfuse Inc. under the POWR-GARD® SPNH series. This product is currently obsolete and no longer in active production. Finding suitable alternatives is necessary to maintain circuit protection in renewable energy installations utilizing equivalent electrical and mechanical specifications.

Substiute Parts

SPNH350.X3LDLMS

Littelfuse Inc.In Stock: 910SPNH350.X3LDLMS Datasheet

Current PartRFQ

PV-350A-3L-BU-15

Eaton - Bussmann Electrical DivisionIn Stock: 812PV-350A-3L-BU-15 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the SPNH350.X3LDLMS is determined by the following criteria:

Critical Electrical Parameters:

• Current Rating: 350A (must match exactly)
• Voltage Rating (DC): 1.5 kVDC (must match exactly)
• Breaking Capacity: Must support rated voltage and current
• Melting I²t: Thermal time constant for coordination with circuit protection

Critical Mechanical Parameters:

• Mounting Type: Bolt Mount (required for physical installation compatibility)
• Package / Case: Rectangular, Blade configuration
• Dimensions: Physical footprint compatibility with mounting structure

Application & Compliance:

• Applications: Solar (Photovoltaic)
• Approval Agencies: Certifications for renewable energy installations

The PV-350A-3L-BU-15 from Eaton - Bussmann Electrical Division meets the electrical requirements (350A, 1.5 kVDC) and mechanical compatibility (bolt mount, rectangular blade package) required for direct substitution in photovoltaic systems.

Parameter Comparison

Engineering Selection Recommendations

The PV-350A-3L-BU-15 is the recommended substitute for the obsolete SPNH350.X3LDLMS based on the following engineering criteria:

Product Status Alignment: The substitute maintains active product status from Eaton - Bussmann Electrical Division, ensuring continued availability and support in contrast to the obsolete Littelfuse product.

Electrical Specification Compliance: Both units satisfy the critical electrical requirements of 350A current rating and 1.5 kVDC voltage rating. The substitute provides superior breaking capacity (100 kA versus 30 kA), which represents an enhancement to the protective capability of the circuit.

Approval and Certification: The Eaton - Bussmann unit carries gPV class certification specifically for photovoltaic applications, aligning with the intended solar installation environment of the original component.

Mechanical Compatibility: The bolt mount configuration and rectangular blade package remain consistent with mounting infrastructure. The dimensional increase in height (3.583" versus 2.874") is the principal mechanical consideration and must be validated against available mounting space in the specific installation.

Thermal Characteristic Differences: The substitute exhibits elevated melting I²t (195000 versus 75000), indicating slower thermal response. System designers must evaluate the impact on coordination timing within the broader protection scheme.

Frequently Asked Questions (FAQ)

Q: Can the PV-350A-3L-BU-15 directly replace the SPNH350.X3LDLMS? A: Direct electrical and functional replacement is supported. The bolt mount configuration and rectangular blade package are mechanically compatible. The height dimension increase (0.709 inches) must be verified against available mounting space in the installation.

Q: Why do the melting I²t values differ significantly between the two parts? A: The melting I²t parameter represents the thermal time constant of the fuse element. The substitute's higher value (195000 versus 75000) indicates a slower thermal response characteristic. This difference must be evaluated in context of the broader circuit protection coordination requirements.

Q: Are both parts suitable for photovoltaic system applications? A: Yes. Both components are specified for solar (photovoltaic) applications. The substitute carries gPV class certification, which is specifically designated for photovoltaic installations.

Q: What is the significance of the breaking capacity difference (100 kA versus 30 kA)? A: Breaking capacity is the maximum fault current the fuse can safely interrupt at the rated voltage. The substitute's higher breaking capacity (100 kA) provides enhanced protective performance in high-fault-current environments.

Q: Must I perform any system-level validation before implementation? A: Physical fit verification of the substitute within the mounting structure is required due to the increased height dimension. Additionally, review of circuit protection coordination to account for the different melting I²t characteristic is recommended as part of standard engineering practice.