SF152Y Thermal Fuse Specs: Complete Data & Ratings

20 December 2025 0

The SF152Y thermal fuse is commonly rated 15 A, 250 VAC with a nominal cutoff temperature typically listed at 157 °C (315 °F). This numeric snapshot matters because the device serves as a last-line overtemperature cutoff in many household and light‑industrial heating appliances, protecting against sustained overheating that other controls may miss.

This article delivers full thermal and electrical specs, performance limits, installation/testing guidance, cross‑references, and a sourcing/safety checklist so engineers and technicians can apply the correct part and avoid failures.

1 — Quick overview & part identification (background)

SF152Y Thermal Fuse Specs: Complete Data & Ratings

1 — What the SF152Y is: form factor, manufacturers, markings

Point: The SF152Y is an axial, metal‑can thermal cutoff in the “jet” style with insulated axial leads or bare terminals. Evidence: Typical markings on devices include the SF152Y type code, a three‑digit temp code, and a small approval/lot stamp as shown on standard datasheets. Explanation: Photographic identification and checking the stamped cutoff code against the datasheet are essential to avoid substituting parts with different trip temperatures or tolerances.

2 — How SF152Y fits the SF-series family

Point: SF152Y sits in the SF-series family alongside SF152E and other variants that differ mainly by nominal cutoff and tolerance. Evidence: Distributor and manufacturer datasheets list SF152E at a lower nominal cutoff band and slightly different tolerance limits. Explanation: A short comparison helps a technician choose SF152Y when a higher nominal trip or different tolerance is required; always match the temp band rather than form factor alone.

2 — Absolute specifications & electrical ratings (data)

1 — Temperature rating, cutoff vs. operating temperature

Point: Nominal cutoff for SF152Y is typically 157 °C (315 °F); manufacturers list variants in roughly the 152–157 °C band. Evidence: Datasheet tables distinguish cutoff (the irreversible open) from allowable operating/hold temperature, and list tolerances ±3–5 °C on many parts. Explanation: Designers must quote vendor datasheet cutoff and convert units; do not use the part at sustained ambient temperatures near cutoff without derating.

2 — Current, voltage, and interrupting capacity

Point: Rated current is 15 A at 250 VAC; rated values indicate maximum steady‑state limits under specified ambient and mounting conditions. Evidence: Datasheets specify continuous current, recommended max steady‑state current, insulation resistance and dielectric strength figures, and sometimes interrupting capacity. Explanation: “Rated” does not guarantee tolerance to large inrushes — confirm interrupting ratings and consider series protection or contactors for inductive loads.

3 — Mechanical & thermal performance (data)

1 — Time-to-trip characteristics and thermal behavior

Point: Trip time depends on heat source, ramp rate, ambient, and mounting; a slow ramp near cutoff can cause long residence times before trip. Evidence: Time‑to‑trip curves in vendor literature show wide variance with mounted heat sinking and airflow. Explanation: For validation, perform ramp tests at controlled rates and report sample size and statistics to capture spread and avoid nuisance trips in production.

2 — Environmental limits and derating guidance

Point: Humidity, vibration, and elevated ambient reduce margin; derating extends life and reduces false trips. Evidence: Typical limits list non‑condensing humidity, vibration resistance levels, and recommended max operating ambient. Explanation: Use rule‑of‑thumb derating (see table) and reduce continuous current at higher ambient to maintain safe margin.

PartNominal CutoffTolerance
SF152Y157 °C / 315 °F±3–5 °C
SF152E152 °C / 306 °F±3–5 °C
Ambient (°C)Suggested continuous current derate
≤25100% rated
25–50Reduce 10–25%
>50Consult datasheet; use next higher rating

4 — Installation, testing & replacement guidelines (method)

1 — Proper mounting and heat-management best practices

Point: Correct lead length, orientation and thermal isolation prevent premature trips. Evidence: Vendor application notes advise keeping the fuse away from direct soldering heat and suggest heat‑sleeves and strain relief. Explanation: Follow a step‑by‑step checklist: allow cooling after soldering, use heat‑shields, secure leads to prevent vibration, and avoid direct mounting on heat sinks unless specified.

  1. Verify part code and temp stamp against datasheet.
  2. Use heat‑sleeve or clamp; keep leads free of strain.
  3. Avoid direct solder contact on the body; use recommended solder times/temperatures.
  4. Document lot and install position in service records.

2 — Bench and in-system testing procedures

Point: Bench verification requires a calibrated oven and thermocouple; in-system testing emphasizes safety. Evidence: Recommended ramp rates and oven procedures are provided in standards and vendor test guides. Explanation: For bench test, use a controlled ramp (e.g., 3–5 °C/min), attach thermocouple at the device body, record trip time and temp, and establish pass/fail acceptance criteria tied to datasheet tolerance.

5 — Typical applications & cross‑reference parts (case)

1 — Common applications and why SF152Y is chosen

Point: Typical uses include small ovens, air fryers, heaters, and power supplies where a compact, high‑current cutoff is required. Evidence: Application notes list motor/element cutoff examples showing SF152Y selection for its 15 A rating and axial form. Explanation: Selection rationale combines desired trip temp, current capability, and mechanical fit; SF152Y is chosen when mid‑150s °C cutoff and 15 A rating align with the thermal design.

2 — Cross-reference and approved replacements

Point: Equivalents exist across families; replacement rules require matching cutoff, current, approvals and fit. Evidence: Cross‑reference tables in distributor catalogs list family equivalents and variant codes. Explanation: Replace only with parts matching cutoff temp, continuous current rating and safety approvals (UL/CSA/VDE) and verify mechanical fit and lot traceability to avoid counterfeit or mismarked parts.

6 — Sourcing, certification & safety checklist (action)

1 — Where to source genuine parts and procurement tips

Point: Obtain from authorized distributors or OEM spare channels and verify incoming markings and certifications. Evidence: Procurement best practices call for certified vendor lists, lot traceability and sample inspection. Explanation: Sample PO checklist: part number, vendor name, lot number, date code, test report, and certification marks; check packaging counts and perform incoming inspection on first lots.

2 — Designer & service safety & compliance checklist

Point: Compliance requires datasheets, safety marks and in‑system testing. Evidence: Product safety files list required reports and test evidence. Explanation: Must‑do signoff includes: verified datasheet copy, UL/CSA/VDE marks, bench trip records, installation photos, and disposal handling per local regulations.

Summary

  • Nominal rating: 157 °C cutoff, 15 A, 250 VAC — always confirm on the vendor datasheet before final design or replacement.
  • Match temperature, current and safety approvals when replacing; form factor alone is insufficient and can create hazards.
  • Follow mounting and ramp‑test best practices to avoid nuisance trips or safety failures; document lot and test records for signoff.

Frequently Asked Questions

What are the key thermal fuse specs for SF152Y thermal fuse?

The key thermal fuse specs are nominal cutoff temperature (~157 °C / 315 °F), rated current (15 A), rated voltage (250 VAC), tolerance band (typically ±3–5 °C), and documented insulation/dielectric figures. Verify these on the official datasheet and use controlled bench ramp tests for validation before field use.

Can SF152Y be used with resistive and inductive loads?

SF152Y is specified for 15 A resistive loads at 250 VAC, but inductive loads with high inrush may require additional protection. Confirm interrupting capacity and consider series devices (fuses, contactors) for inductive circuits; always validate under worst‑case inrush and ambient conditions.

How should a technician test and record SF152Y thermal fuse performance?

Use a calibrated oven and thermocouple mounted to the device body, apply a controlled ramp (3–5 °C/min recommended), record trip temperature and time across multiple samples, and compare to datasheet tolerance. Maintain pass/fail logs, lot numbers, and installation photos for compliance and traceability.