OptiFuse announces the release of our 2024 Automotive Aftermarket Circuit Protection Catalog

Whether you&#8217;re seeking advice, clarification, or insight on a particular topic, our experts are here to help. So, what&#8217;s on your mind? Ask away!

Got a question? Ask your OptiFuse engineer

span

Useful Links

1675 Pioneer Way, Suite CEl Cajon, CA 92020 USA

sales@optifuse.com

1-619-593-5050

OptiFuse

Ask the Expert: OptiFuse Blog

Blog

Get expert advice on fuses, circuit breakers, and electrical safety trends with the OptiFuse blog. Stay informed on the latest in circuit protection and components.

Blog | OptiFuse

Home

Optifuse

Minimize downtime and keep vehicles or equipment online with OptiFuse’s <a href="https://www.optifuse.com/circuit-breakers/blade-style-circuit-breakers-46/349/">ACB2-PL</a> a Type I (automatic reset), blade-style circuit breaker designed to drop into ATO/ATC fuse locations while adding the convenience of automatic reset. Universal, scored blades make fit-up simple when terminal length is unknown, and conformance to SAE J553 ensures dependable performance in demanding environments.

<ul>
<li>Type I Auto-Reset: Automatically recovers after a fault clears</li>
<li>Voltage / Current Ratings: 14 VDC (note: 12VDC @ 40A); 5 A to 40 A range covers common loads</li>
<li>Universal blade terminals</li>
<li>SAE J553 compliant for automotive blade-style circuit breaker requirements</li>
<li>Retail packs available for service counters and MRO kits.</li>
</ul>

<ul>
<li>Automotive, light &amp; <a href="https://www.optifuse.com/industries/heavy-duty-vehicles/">heavy-duty vehicle</a> accessory circuits</li>
<li><a href="https://www.optifuse.com/industries/marine/">Marine</a> &amp; <a href="https://www.optifuse.com/industries/recreational-vehicles-rvs/">RV</a> distribution panels and add-on upfits</li>
<li>Fleet/MRO environments where quick resets reduce service calls</li>
<li>Field-service tools, pumps, winches, lighting, and controllers requiring ATO/ATC form factor.</li>
</ul>

If you’re swapping standard blade fuses and suffering unnecessary call-outs, ACB2-PL brings resettable convenience without re-engineering the harness. Its Type I auto-reset behavior helps restore operation once the overload clears. For drop-in replacements and upfits see <a href="https://www.optifuse.com/blog/replace-fuse-with-circuit-breaker/">Can I Replace a Fuse with a Circuit Breaker?</a> And <a href="https://www.optifuse.com/blog/why-circuit-breaker-keeps-tripping/">What Causes Breakers to Trip</a>? for troubleshooting and coordination context.
To ensure you select the best protection for your application, <a href="https://www.optifuse.com/blog/optifuse-fuse-selection-guide/">see our Circuit Protective Device Selection Guide for complete context.</a>

<a href="https://www.optifuse.com/sebastian-castaneda-optifuse-profile/">Sebastian Castañeda</a>, Application Engineer at OptiFuse, supports customers with technical solutions, custom circuit protection design, and training. He provides tailored guidance and shares expert insights on the OptiFuse Blog.

Auto-Reset Blade Protection for 12 V Systems: The ACB2-PL

Replace ATO/ATC fuses with the OptiFuse ACB2-PL Type I auto-reset blade breaker. 14 VDC, 5-40A ratings, SAE J553 compliant.

ACB2-PL Auto-reset Blade Circuit Breaker (Type I) | OptiFuse

https://cms.optifuse.com/uploads/2025/11/OptiFuse-ACB2-PL-Auto-Reset-Blade-Style-Circuit-Breaker.png

https://www.optifuse.com//avatar/37465ca0211ae8a73d49655e93db6660?s=96&d=mm&r=g

Oihane Fernandez de Retana

When you need quick, dependable overcurrent protection in tight spaces, OptiFuse’s <a href="https://www.optifuse.com/fuses/electronic-glass-ceramic-fuses-39/248/">FSE/FSE-P</a> series delivers. This fast acting 5x15mm glass cartridge fuse (with optional axial-lead version) is UL 248-14 recognized and purpose-built for clear visual inspection and reliable interruption in low/medium-voltage AC circuits.

<ul>
<li>Voltage ratings (model dependent) up to 300 VAC for select ratings; 250 VAC for others. See <a href="https://www.optifuse.com/optifuse_ecommerce_tools/datasheets/FSE.pdf">datasheet</a> for more information</li>
<li>Interrupting Ratings:
<ul>
<li>50A @ 300 VAC</li>
</ul>
</li>
<li>Form factor: 2AG / 5x15mm glass cartridge; optional FSE-P axial-lead variant.</li>
</ul>

<ul>
<li>AC power supplies, control boards, and instrumentation</li>
<li>Appliance and <a href="https://www.optifuse.com/industries/consumer-electronics/">small equipment</a> branch protection</li>
<li>Auxiliary AC circuits in panels requiring fast-acting response and visual fuse status, pair with the right fuse holder, see</li>
</ul>

FSE combines a compact 2AG footprint with fast-acting performance and straightforward visual inspection, ideal when space is limited but compliance and reliability still matter. With UL 248-14 recognition and published AC interrupting ratings per amperage, it’s a practical, drop-in choice for a wide range of AC applications.
To learn how to select the right tube fuse, read our <a href="https://www.optifuse.com/blog/choose-a-tube-fuse/">How to Choose a Tube Fuse</a> article or <a href="https://www.optifuse.com/blog/optifuse-fuse-selection-guide/">see our Fuse Selection Guide for complete context</a>.

Pair FSE with <a href="https://www.optifuse.com/fuse-holders-blocks-and-accessories/electronic-glass-ceramic-fuses-14/fuse-clip-19/">CSC 5 mm fuse clips</a> for compact PCB mounting. Match the clip’s current and temperature ratings to your application and verify the 2AG/5 mm size fit

Fast-Acting Protection for Compact AC Circuits: The FSE Fuse

Protect compact AC circuits with OptiFuse FSE fast-acting 5×15 mm fuses featuring UL recognition and clear glass design.

FSE Fast-Acting 2AG (5x15mm) AC Fuses | OptiFuse

https://cms.optifuse.com/uploads/2025/11/OptiFuse-FSE-5×15-mm-Fast-Acting-Glass-Fuse.png

In <a href="https://www.optifuse.com/industries/industrial-electronics/">industrial and machine-control systems</a>, the Short-Circuit Current Rating (SCCR) defines how much fault current a control panel (or component) can safely endure without catastrophic failure. If available fault current at the installation point exceeds the SCCR, components can rupture, arcs can ignite, and people and equipment are at risk.Engineers should design for the absolute worst case, but also the highest fault currents that could exist over time (e.g., service upgrades or plant expansions). SCCR is the safety margin that protects you on that worst day.

<h2>Key Terms</h2>
<ul>
<li>Available Fault Current: The prospective short-circuit current at the panel’s supply terminals if a fault occurs (to ground or between phases). In figure 1, available fault current is denoted by Maximum Possible Peak Current.</li>
<li>SCCR (Short-Circuit Current Rating): An equipment rating: the maximum fault current a component or assembled panel can withstand for a defined test duration without unacceptable damage.</li>
<li>Interrupting Rating (IR): For fuses and breakers: the maximum fault current the device can safely interrupt under specified conditions. (IR is not the same as SCCR.)</li>
</ul>
<ul>
<li>Coordination / Let-Through Energy: A device might interrupt a high fault, but the energy let through (I²t/peak) can still damage downstream parts if not coordinated. In figure 1, peak-let through current is denoted by Peak Let-Thru.</li>
</ul>

Rule of thumb: The panel’s marked SCCR must be ≥ the available fault current at the installation location. Installing where available fault current exceeds SCCR is unsafe and non-compliant.

<h2>Why It Matters</h2>
During a short circuit, fault current follows all available return paths, dividing according to their impedances. If any device in those paths can’t withstand the stress, you risk cascading failures, arc-flash hazards, and extended downtime. Designing with SCCR in mind ensures the enclosure and internals remain intact long enough for upstream protection to clear the event.

<h2>Mini-Example</h2>
Starting from the load side, Branch 1 is protected by an MCCB with 10 kA SCCR and Branch 2 by an MCCB with 15 kA SCCR. Because Branch 1 is the lowest of the two, the assembly is limited to ≤ 10 kA SCCR at this stage.
Upstream, the fusible switch currently uses RK5 fuses. In figure 2, the RK5 let-through downstream of the switch is 21 kA, which exceeds multiple downstream component ratings. The power distribution block (PDB) is 10 kA SCCR, so as configured the system is not acceptable.
 
<img decoding="async" src="http://cms.optifuse.com/uploads/2025/11/SCCR-Coordination-Example-with-MCCBs-RK5-and-Class-J-Fuses-02-02.png" />
 
Mitigation: Replace the <a href="https://www.optifuse.com/fuses/industrial-and-ul-fuses-63/509/">RK5</a> with a Class J fuse (properly sized). Class J’s current-limiting performance reduces the let-through to ≈ 10 kA, so downstream devices experience ≤ 10 kA during a fault. With that limitation:
<ul>
<li>The 10 kA PDB is protected within its SCCR.</li>
<li>Branch 1 (10 kA) and Branch 2 (15 kA) are both within their SCCR.</li>
</ul>
Result: The panel can be assigned 10 kA SCCR (governed by Branch 1), and the assembly becomes compliant once the feeder fuses are upgraded to Class J and properly coordinated.

<h2>Key Takeaways</h2>
<ul>
<li>SCCR defines how much fault energy your system can safely withstand.</li>
<li>It must always be ≥ available fault current at the install location.</li>
<li>Current-limiting protection is the practical lever to raise effective SCCR.</li>
</ul>
SCCR isn’t about nominal operation, instead, it’s about the worst minute your system may ever face. Build in margin and coordinate protection. If you need a high-performance feeder fuse to help elevate SCCR, consider a current-limiting UL 248 Class J option like <a href="https://www.optifuse.com/fuses/industrial-and-ul-fuses-63/523/">OptiFuse T6J</a>. <a href="https://www.optifuse.com/blog/optifuse-fuse-selection-guide/">See our full Fuse Selection Guide for complete context</a>.

Introduction to SCCR

Protect panels and components from fault currents with SCCR. Learn ratings, coordination, and current-limiting strategies.

Introduction to SCCR (Short-Circuit Current Rating) | OptiFuse

https://cms.optifuse.com/uploads/2025/11/Current-waveform.png

In designing protection systems, engineers often hear that AC arcs are easier to interrupt than DC arcs. This principle has major implications in fuse sizing, the selection of circuit breakers, and overall system safety. In this article, we’ll explain why AC is easier to extinguish and what that means for fuse and circuit designs. We’ll also discuss how OptiFuse products address quenching challenges and provide guidance on selecting the right AC fuse vs DC fuse for your application.

<h2>What Quenching an Arc Means</h2>
When a fuse or circuit breaker opens under fault conditions, an electrical arc is formed between the separating contacts. The arc conducts current across an air gap and must be extinguished (quenched) to stop current flow and isolate the fault.
Quenching depends on:
1. The voltage waveform (its zero crossings)
2. The ability of the arc path to become non-conductive (by cooling, elongation, increasing voltage stress)
3. System inductance, capacitance, and stray energy
Because of these factors, AC and DC behave very differently in arc extinction.

<h2>Comparing Arc Quenching in AC vs DC Systems </h2>
AC arcs are easier to quench due to zero crossings, cooling opportunities, and polarity reversal, while DC arcs require specialized design considerations. Choosing the right fuse or breaker, ensures safe and reliable protection for both AC and DC systems.

<ul>
<li>Alternating current (AC) naturally alternates up and down, rising to a peak voltage and then reversing to a negative peak. Each time the voltage changes direction, it passes through 0 volts (120 times per second in U.S. 60 Hz systems). At each zero crossing, the arc momentarily loses its sustaining current, giving it a natural chance to extinguish.</li>
<li>Direct current (DC) behaves differently: the voltage is constant and never passes through zero, so the arc can continue indefinitely unless external measures disrupt it.</li>
</ul>

<ul>
<li>Each zero crossing in AC provides time for the arc to cool and the air gap to de-ionize. Once the ionized path collapses, re-ignition is less likely, especially as the contact gap widens.</li>
<li>With DC, the current is continuous, keeping the plasma energized and making the arc much harder to extinguish.</li>
</ul>

<ul>
<li>In AC, the voltage polarity flips every half cycle, which further disrupts residual ionization in the arc path. This reversal helps prevent the arc from re-establishing.</li>
<li>In DC, the polarity never changes, so this “reset effect” is absent.</li>
</ul>

<h2>Design Implications for Fuses and Circuit Breakers</h2>
Because AC is easier to quench, protective devices must be designed differently for AC vs. DC:
<ul>
<li>Fuse time-current curves: DC-rated fuses must handle a sustained arc and therefore often require longer arc paths, more ceramic filler, or advanced interruption features.</li>
<li>Voltage ratings: A fuse or circuit breaker rated for 250 V AC may not be safe at 250 V DC. DC interruption requires more robust construction and often has lower DC ratings than AC.</li>
<li>De-rating strategies: DC systems typically need more conservative derating of protection devices to ensure safe operation.</li>
</ul>

<h2>How OptiFuse Ensures Reliable AC and DC Arc Protection</h2>
At OptiFuse, we design and source fuses and circuit protection devices with ratings suited for their intended environments: AC, DC, or hybrid systems.
<ul>
<li>For DC interruption (battery systems, solar, energy storage), select fuses explicitly rated for DC and sized to your available fault current: Class T (<a title="https://nam02.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.optifuse.com%2Ffuses%2Findustrial-and-ul-fuses-63%2F496%2F&amp;data=05%7C02%7Craniahc%40triadcomponentsgroup.com%7C876a2c0394594d0e5a7e08de109e4079%7C4e4d40c7a6d94d2aa01f5c29a5888588%7C0%7C0%7C638966469025937490%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&amp;sdata=LQAr5hZuN5rx9FVsJ9Pa%2BjXFzPUU%2BJuehzSgX4wpJb8%3D&amp;reserved=0" href="https://nam02.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.optifuse.com%2Ffuses%2Findustrial-and-ul-fuses-63%2F496%2F&amp;data=05%7C02%7Craniahc%40triadcomponentsgroup.com%7C876a2c0394594d0e5a7e08de109e4079%7C4e4d40c7a6d94d2aa01f5c29a5888588%7C0%7C0%7C638966469025937490%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&amp;sdata=LQAr5hZuN5rx9FVsJ9Pa%2BjXFzPUU%2BJuehzSgX4wpJb8%3D&amp;reserved=0" data-outlook-id="e95c4645-f5c9-4b91-bc53-79fa67aa8896">F6T 300 VDC</a> / <a title="https://nam02.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.optifuse.com%2Ffuses%2Findustrial-and-ul-fuses-63%2F495%2F&amp;data=05%7C02%7Craniahc%40triadcomponentsgroup.com%7C876a2c0394594d0e5a7e08de109e4079%7C4e4d40c7a6d94d2aa01f5c29a5888588%7C0%7C0%7C638966469025970383%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&amp;sdata=BAVo7QYhMH8XG3D97p942LYCele7uTw7M3vfiz%2FlRFA%3D&amp;reserved=0" href="https://nam02.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.optifuse.com%2Ffuses%2Findustrial-and-ul-fuses-63%2F495%2F&amp;data=05%7C02%7Craniahc%40triadcomponentsgroup.com%7C876a2c0394594d0e5a7e08de109e4079%7C4e4d40c7a6d94d2aa01f5c29a5888588%7C0%7C0%7C638966469025970383%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&amp;sdata=BAVo7QYhMH8XG3D97p942LYCele7uTw7M3vfiz%2FlRFA%3D&amp;reserved=0" data-outlook-id="da96149b-1700-4d75-b743-c359dba51bb0">F3T 160 VDC</a>) for higher-voltage/high-AIC feeders, <a title="Original URL:
https://www.optifuse.com/fuses/automotive-bolt-on-fuses-37/501/

Click to follow link." href="https://nam02.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.optifuse.com%2Ffuses%2Fautomotive-bolt-on-fuses-37%2F501%2F&amp;data=05%7C02%7Craniahc%40triadcomponentsgroup.com%7C876a2c0394594d0e5a7e08de109e4079%7C4e4d40c7a6d94d2aa01f5c29a5888588%7C0%7C0%7C638966469025995127%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&amp;sdata=k%2FCdxUdzpddqB6RYbFKzTbDbfo89SeV6VkGTOpgYfC0%3D&amp;reserved=0" data-outlook-id="f70e2196-2300-48db-bdf8-b3b97635ea98">ANE-M 80 VDC</a> where ignition protection is required, and <a title="https://nam02.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.optifuse.com%2Ffuses%2Fautomotive-bolt-on-fuses-37%2F233%2F&amp;data=05%7C02%7Craniahc%40triadcomponentsgroup.com%7C876a2c0394594d0e5a7e08de109e4079%7C4e4d40c7a6d94d2aa01f5c29a5888588%7C0%7C0%7C638966469026004519%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&amp;sdata=UfpkrxYCrMxn%2FjYY8IwOswJq9881ShFuYSakuTHWA4E%3D&amp;reserved=0" href="https://nam02.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.optifuse.com%2Ffuses%2Fautomotive-bolt-on-fuses-37%2F233%2F&amp;data=05%7C02%7Craniahc%40triadcomponentsgroup.com%7C876a2c0394594d0e5a7e08de109e4079%7C4e4d40c7a6d94d2aa01f5c29a5888588%7C0%7C0%7C638966469026004519%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&amp;sdata=UfpkrxYCrMxn%2FjYY8IwOswJq9881ShFuYSakuTHWA4E%3D&amp;reserved=0" data-outlook-id="cb270c11-d522-42ff-9bef-72c36ca7affe">MIDA</a>/<a title="Original URL:
https://www.optifuse.com/fuses/automotive-bolt-on-fuses-37/234/

Click to follow link." href="https://nam02.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.optifuse.com%2Ffuses%2Fautomotive-bolt-on-fuses-37%2F234%2F&amp;data=05%7C02%7Craniahc%40triadcomponentsgroup.com%7C876a2c0394594d0e5a7e08de109e4079%7C4e4d40c7a6d94d2aa01f5c29a5888588%7C0%7C0%7C638966469026013233%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&amp;sdata=9eHT%2BVhBbH5P2Sztp8mE3%2FW%2BSNznPDjKs%2BlOC7Hzlk8%3D&amp;reserved=0" data-outlook-id="f52de0f7-57a2-4a90-b023-de41cd57f771">ANE</a> for 58 VDC / 32 VDC vehicle and auxiliary battery circuits.</li>
<li>For AC applications, designers can choose from a broader range of devices that benefit from natural zero crossings, simplifying arc quenching and reducing component stress.</li>
</ul>
In applications where DC protection is required (battery systems, solar, EVs), the choice of fuse construction becomes critical. While a simple fuse link is often fine in AC systems, in DC you need engineered arc suppression.
 
By understanding why AC arcs are easier to extinguish than DC arcs, engineers can select the right fuse and circuit breaker for AC vs DC applications ensuring both performance and safety in their systems. OptiFuse offers products designed for both AC and DC arc interruption, ensuring reliable protection and system safety. <a href="https://www.optifuse.com/blog/optifuse-fuse-selection-guide/">See our full Fuse Selection Guide for complete context</a>.

Why is AC Voltage and Current Easier to Quench than DC?

Learn why AC arcs are easier to extinguish than DC arcs, and what this means for fuse and breaker design. See how OptiFuse ensures safe protection.

https://cms.optifuse.com/uploads/2025/10/AC-vs-DC-Waveforms-Showing-Arc-Quenching-Differences-1.png

When your system demands high current protection, especially in battery, marine, or heavy-duty DC applications, the OptiFuse <a href="https://www.optifuse.com/circuit-breakers/high-amperage-heavy-duty-circuit-breakers-44/300/">153</a> Series is built to handle severe fault conditions with reliability and safety in mind.

<ul>
<li>Interrupt rating: 3,000 A @ 30 VDC (ABYC / marine compliant)</li>
<li>Voltage range: Up to 42 VDC; stainless-stud variants (153-SS) rated 48 VDC</li>
<li>Amperage options: 25 A – 200 A</li>
<li>Rugged build: UL 94V-0 thermoset body, nickel/stainless studs, IP67 waterproof, SAE J1171 ignition-protected</li>
<li>Manual reset: Resettable design reduces downtime vs. single-use fuses</li>
</ul>

<ul>
<li><a href="https://www.optifuse.com/industries/marine/">Marine</a> power distribution (ignition-protected for engine compartments)</li>
<li>Automotive and <a href="https://www.optifuse.com/industries/heavy-duty-vehicles/">heavy-duty</a> vehicle battery protection</li>
<li><a href="https://www.optifuse.com/industries/recreational-vehicles-rvs/">RV</a> and off-grid battery systems</li>
<li>Industrial DC equipment and backup power circuits</li>
</ul>

Designed with ¼ &#8211; 28 for surface mounting, ensuring secure, vibration-resistant terminations. This standard mounting style allows installers to use common heavy-gauge ring lugs, making it ideal for high-amperage applications.

When a system calls for high current protection with reliability and serviceability, the 153 Series stands out. Unlike single-use fuses, it allows quick resetting after a fault. And unlike lower-grade breakers, it’s engineered to survive in demanding, high-fault environments.
For a deeper dive into when to choose fuses vs circuit breakers, check out <a href="https://www.optifuse.com/blog/fuses-vs-circuit-breakers/">OptiFuse’s comparison guide</a>. To ensure you select the best protection for your application, <a href="https://www.optifuse.com/blog/optifuse-fuse-selection-guide/">see our Circuit Protective Device Selection Guide for complete context.</a>

OptiFuse 153 Series: High-Current DC Circuit Breakers for Marine and Automotive Use

Discover OptiFuse 153 Series high-current DC circuit breakers—resettable, rugged, and ideal for marine, RV, and heavy-duty battery systems.

153 Series: Resettable DC Circuit Breakers for Marine & Automotive | OptiFuse

https://cms.optifuse.com/uploads/2025/10/High-Amperage-Waterproof-Circuit-Breakers-–-25A-to-300A-with-Automatic-or-Manual-Reset.png

When dealing with overcurrent protection in telecommunications or control circuits, OptiFuse’s <a href="https://www.optifuse.com/fuses/telecom-fuses-51/360/">FPT</a> and FPT-C series is a reliable drop-in replacement for Bussmann GMT-style fuses, optimized to manage arcs and ensure dependable circuit isolation. The FPT family is engineered to interrupt both AC and DC fault currents, and its construction illustrates how design choices can assist arc suppression under challenging conditions:

<ul>
<li>High interrupting ratings: 300 A @ 125 VAC / 125 VDC, 450 A @ 60 VDC</li>
<li>Alarm indication: Supports LED or audio alarms for blown fuse detection, reducing downtime in complex systems</li>
<li>Durable body: PPS housing (UL94V-0 rated) with transparent polycarbonate cover for visibility</li>
<li>Fuse cover (-C variant): Clear removable cover adds flexibility and protection against contaminants</li>
<li>Color-coded amperages: Industry-standard coloring makes ratings easy to identify at a glance</li>
</ul>

<ul>
<li>Telecom, control, and signal circuits where AC and DC may coexist</li>
<li>Backup power systems and battery-fed lines</li>
<li>Compact enclosures needing fast-acting, inspection-ready overcurrent protection</li>
<li>Sub-circuits, power desks, or interface modules with moderate fault currents</li>
</ul>

The FPT line combines robust interrupting performance with alarm-indication features and compact design. Whether you need clear blown-fuse visibility, alarm circuit integration, or a removable cover for safety, the FPT / FPT-C provides flexibility and reliability for telecom and control applications.
To understand how FPT interrupts fault currents, see our blog on the <a href="https://www.optifuse.com/blog/how-a-fuse-works/">fundamentals of how a fuse works.</a> To learn how to select the right fuse for your specific needs, <a href="https://www.optifuse.com/blog/optifuse-fuse-selection-guide/">see our Fuse Selection Guide for complete context</a>

Optimized Overcurrent Protection for Telecom and Control Circuits: The FPT Fuse

Discover FPT fuses with high interrupting ratings and alarm indicators for reliable overcurrent protection in AC/DC telecom and control circuits.

FPT Fuses for Reliable Telecom & Control Protection | OptiFuse

https://cms.optifuse.com/uploads/2025/10/OptiFuse-FPT-Series-Fuse-for-Telecom-and-Control-Circuits-2.png