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A circuit breaker that keeps tripping can be frustrating, especially in aftermarket DC systems where accessories are added over time.From auxiliary lighting and compressors to pumps, fans, and RV electronics, increased demand often pushes a 15 amp circuit to its limit. When this happens, the first assumption is often a simple upgrade: Can a 15 amp breaker be replaced with a 20 amp breaker?

<h2>Can a 15 amp breaker be replaced with a 20 amp breaker?</h2>
In most cases, not unless the entire circuit is rated for 20 amps.
A circuit breaker is not just a resettable switch with a labeled current rating. It is an overcurrent protection device that protects wiring and connected components by interrupting power from excessive current during overloads and fault conditions.
Installing a larger breaker without checking the rest of the circuit can create a dangerous condition where the breaker allows more current than the circuit was designed to handle.

You can only replace a 15 amp breaker with a 20 amp breaker if the entire circuit is suitable for 20 amp operation. That includes:
<ul>
<li>Wire gauge, wire length, and insulation temperature rating</li>
<li>Breaker voltage and interrupt rating</li>
<li>Terminal and connector ratings</li>
<li>Switch, relay, fuse block, or distribution block rating</li>
<li>Load current and expected inrush current</li>
<li>Reset type</li>
<li>Installation environment</li>
</ul>
 
If any part of the circuit is only suitable for 15 amps, the breaker should not be upsized to 20 amps.
A larger breaker does not make the circuit stronger. It only increases the current allowed before it trips, which can leave wiring and components unprotected.

<h2>Wire Gauge Comes First</h2>
In automotive, marine, RV, and equipment circuits, the breaker’s primary role is to protect the wiring, not just the connected devices.
If the wire is only suitable for a 15 amp circuit, replacing the breaker with a 20 amp version may allow the conductor to carry more current than it should. That can lead to overheated insulation, damaged connectors, burned terminals, excessive voltage drop, or intermittent equipment operation.
In low-voltage DC systems, wire size affects both safety and performance. Undersized wire can overheat, but it can also create voltage drop that prevents pumps, compressors, fans, actuators, radios, and electronics from operating correctly.
Before moving from a 15A breaker to a 20A breaker, confirm that the wire gauge, wire length, terminals, splices, and connectors are all rated for the higher current.

A breaker that keeps tripping is not always the wrong breaker. It may be doing exactly what it should do.

<h2>The Load May Be the Real Problem</h2>
A breaker that keeps tripping is not always the result of a defective unit or insufficient rating. In most cases, it is functioning correctly and disconnecting power in response to an overload condition in the circuit.
Common causes include:
<ul>
<li>Too many accessories on one circuit</li>
<li>A pump that is clogged or stalled</li>
<li>A motor with high startup current</li>
<li>A compressor with heavy inrush current</li>
<li>Auxiliary lights drawing more current than expected</li>
<li>A stereo amplifier pulling high current during peaks</li>
<li>Loose, corroded, or damaged wiring</li>
</ul>
 
Before upsizing the breaker, check the actual load current and compare it to the circuit design. If the normal operating current is too close to 15 amps, the circuit may need to be redesigned, not simply fitted with a larger breaker.
 
<h2>Better Fixes Than Upsizing the Breaker</h2>

<h2>So, Can You Replace a 15 Amp Breaker with a 20 Amp Breaker?</h2>
Sometimes, but only if the entire circuit is rated for 20 amps.
Do not replace a 15A breaker with a 20A breaker just to stop nuisance tripping. The breaker may be warning you that the circuit is overloaded, undersized, damaged, or exposed to too much heat.
A 20A breaker may be the right choice for a properly designed 20A circuit. But if the circuit was designed for 15 amps, upsizing the breaker can allow too much current to flow before the breaker opens.
The safest approach is simple: Find the reason for the trip, then size the breaker to the circuit.
 
For complete circuit protection context, see our <a href="https://www.optifuse.com/blog/optifuse-fuse-selection-guide/">Fuse Selection Guide.</a> For application support or fuse selection help, contact OptiFuse at <a href="mailto:sales@optifuse.com">sales@optifuse.com</a>.

<a title="Original URL:
https://www.optifuse.com/sebastian-castaneda-optifuse-profile/

Click to follow link." href="https://nam02.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.optifuse.com%2Fsebastian-castaneda-optifuse-profile%2F&amp;data=05%7C02%7Craniahc%40triadcomponentsgroup.com%7Cba4e1817de2442d45b0108de581a194c%7C4e4d40c7a6d94d2aa01f5c29a5888588%7C0%7C0%7C639045066773787451%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&amp;sdata=%2FNcWZzVi1NVAQA6q3nXS%2FHx0HIdg4xkZw1w3Op%2FsecY%3D&amp;reserved=0" data-outlook-id="2169bcb2-fb9b-4fd1-9c49-5a04847fe53c">Sebastian Castañeda</a> is a circuit protection specialist and technical writer with application-focused experience in technical support and custom protection design. He contributes practical, application-driven insights to the OptiFuse Blog.

Can You Replace a 15 Amp Breaker with a 20 Amp Breaker?

Learn when you can replace a 15 amp breaker with a 20 amp breaker, and why wire gauge, load current, voltage rating, and reset type matter in DC circuits.

Can you Replace a 15 Amp Breaker with a 20 Amp Breaker?

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

Oihane Fernandez de Retana

High-current DC circuits need more than basic overload protection. In RVs, marine systems, emergency vehicles, and other heavy-duty applications, a main feed or auxiliary power circuit may need to handle large loads while still remaining serviceable after a trip.The OptiFuse <a href="https://www.optifuse.com/circuit-breakers/high-amperage-heavy-duty-circuit-breakers-44/304/">353</a> Series is a high-amperage, manual-reset circuit breaker built for these demanding DC applications. With a surface-mount body, 3/8”-16 studs, IP67 ingress protection, and current ratings from 25A to 300A, the 353 is designed for heavy-duty accessory and auxiliary circuits where resettable protection is preferred over a one-time fuse.

The 353 is a Type III manual reset breaker. That means when the breaker trips, it stays open until someone manually resets it.
This is useful in circuits where automatic reconnection is not desired. If a fault occurs on a battery feed, compressor, winch, pump, or high-current accessory circuit, the load should often remain off until the wiring and equipment can be inspected.
Manual reset protection helps prevent cycling into a fault condition.

The OptiFuse 351 Series IP67 automatic-reset breaker (see our <a href="https://www.optifuse.com/blog/351-high-amp-auto-reset-circuit-breaker-ip67/" target="_blank" rel="noopener">351 Series article</a>) is intended for applications where temporary overloads may occur and automatic recovery is preferred after the breaker cools. In these systems, power may be restored without manual intervention once the fault condition clears.
In contrast, the 353 Series is used where any trip condition should remain latched until the circuit is inspected and manually reset. This ensures faults require physical intervention before the circuit is re-energized.
 
The 351 Series is typically selected where brief overloads are expected and continuity of operation is important, while the 353 Series is preferred for applications where a trip should trigger a system check before restoring power.
For more circuit protection context, see our <a href="https://www.optifuse.com/blog/circuit-breakers-reset-types/">Circuit Breaker Reset Types</a> blog.

The 353 is not meant to replace a small blade-style or low-current accessory breaker. It is built for circuits where larger conductors, higher current loads, and rugged mounting are required.
For lower-current ATO/ATC-style circuits, a blade-style breaker may be a better fit. For heavy-duty battery-adjacent protection, the 353 offers a resettable, surface-mount option with larger studs and higher current range.

<ul>
<li>Current range: 25A to 300A</li>
<li>Voltage rating: 48VDC</li>
<li>Reset type: Type III manual reset</li>
<li>Interrupt rating: 3,000A at 30VDC / 44VDC, SAE J1171 ignition protected, ABYC E-11 tested</li>
</ul>
For more inquiries, contact OptiFuse at <a href="mailto:sales@optifuse.com">sales@optifuse.com</a>. <a href="https://www.optifuse.com/blog/optifuse-fuse-selection-guide/">See our Fuse Selection Guide for complete context</a>.

OptiFuse 353 Series: Manual Reset Protection for Heavy-Duty DC Circuits

Learn how the OptiFuse 353 Series manual reset circuit breaker protects high-current DC circuits in RV, marine, emergency vehicle, and heavy-duty applications.

OptiFuse 353 Manual Reset Circuit Breaker for Heavy-Duty DC Circuits

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When a circuit needs individual aftermarket fuse protection out in the harness, an in-line fuse holder is often the cleanest answer.The OptiFuse<a href="https://www.optifuse.com/fuse-holders-blocks-and-accessories/automotive-blade-fuses-4/in-line-fuse-holder-5/23/"> LPR-02</a> is an in-line Regular (ATO/ATC style) blade fuse holder built for vehicle electrical systems where space, contamination, and serviceability all matter. It features an integrated snap-on cover, IP67 ingress protection, a 125VDC / 250VAC rating, and compatibility with Regular blade fuse families from 32V through 125VDC / 250VAC, including 32V, 58V, and 80V options. The LPR-02 is also rated for up to 30A, depending on wire gauge.For compatible fuse options, see our <a href="https://www.optifuse.com/fuses/automotive-blade-fuses-35/201/">ANR</a>, <a href="https://www.optifuse.com/fuses/automotive-blade-fuses-35/202/">ANR-UL</a>, <a href="https://www.optifuse.com/fuses/automotive-blade-fuses-35/204/">ANR58-UL</a>, and<a href="https://www.optifuse.com/fuses/automotive-blade-fuses-35/206/"> ANR80-UL</a> blade fuse series. <a href="https://www.optifuse.com/blog/optifuse-fuse-selection-guide/">See our Fuse Selection Guide for complete context</a>.

An in-line fuse holder puts the fuse directly into the wire run, so the protected circuit can be fused close to the load instead of forcing everything back to a centralized fuse block.
A good real-world example is a car audio hobbyist adding a dedicated fused power lead for an amplifier turn-on circuit, signal processor, or accessory feed. In that kind of install, the goal is usually not to build out a full fuse block for one small branch circuit. It is to add clean, localized protection directly in the harness, with a holder that stays serviceable if the fuse ever needs replacement. That same approach also applies to aftermarket lighting, dash electronics, radar detectors, cameras, and other integrated automotive accessories.

In vehicle applications, exposure to moisture, dust, and corrosive elements is a constant concern. The LPR-02’s integrated snap-on cover helps protect the fuse and contacts by keeping moisture out in wet or humid conditions, while also limiting dust and airborne contamination.
In harsher environments, such as coastal areas or regions where road salt is used, the cover also helps reduce corrosion on fuse terminals. This added protection supports long-term reliability and consistent circuit performance in real-world conditions.

<ul>
<li>IP67 sealed design for water, dust, and airborne pollutants</li>
<li>Regular ATO/ATC blade fuse compatibility</li>
<li>Available in multiple wire gauges, colors, and configurations for custom harness needs. For additional details, please refer to the <a href="https://www.optifuse.com/blog/in-line-fuse-holder-customization/">In-Line Fuse Holder Customization Guide</a>.</li>
</ul>
For custom inquiries, please contact our factory team at <a href="http://sales@optifuse.com/">sales@optifuse.com</a>

Discover more 

LPR-02: A Sealed In-Line Fuse Holder for Hard-Working Vehicle Circuits

Learn where the OptiFuse LPR-02 fits best, why IP67 matters, and how this sealed in-line ATO/ATC fuse holder helps protect car audio and accessory circuits.

LPR-02 In-Line Fuse Holder: IP67 ATO/ATC Protection for Vehicle Circuits

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A short circuit on one branch circuit should not take down an entire system.That is the basic idea behind selective coordination. In practical terms, it means the overcurrent protective device closest to the fault clears first, while upstream devices stay closed so the rest of the system keeps running.In the NEC’s definition, selective coordination is about limiting an outage to the affected circuit or equipment for the full range of available overcurrents, from overload through available fault current.It sounds simple enough, but it becomes a serious design issue once you are dealing with emergency power, legally required standby systems, healthcare facilities, and industrial equipment where downtime can cost thousands of dollars.

<h2>How Coordination Between Overcurrent Protective Devices Is Verified</h2>
Selective coordination is not determined by looking at two device amp ratings and assuming the smaller one will open first. In practice, engineers verify coordination by comparing the upstream and downstream protective devices on a time-current curve.
<img decoding="async" src="http://cms.optifuse.com/uploads/2026/05/GRAPH.png" alt="Graph" />
Comparing the 3A curves of OptiFuse’s TPK-R and FPK-R shows how fuse series can behave very differently at the same fault current. At 10A, the TPK-R-3A opens in about 1 second, while the FPK-R-3A opens in roughly 0.1 to 0.2 seconds. This is exactly why coordination cannot be assumed from amp ratings alone.

<h3>How Time-Current Curves Are Interpreted</h3>
The horizontal axis shows current in amperes, and the vertical axis shows opening time in seconds. If the downstream device clears before the upstream device across the expected range of overcurrent, you are on the right track. If the curves overlap in a meaningful part of the fault range, coordination may be lost.
 
<h3>Overcurrent Conditions Included in Coordination Studies</h3>
Time-current curves are especially important because coordination has to hold across more than one type of event. It is not just about large bolted faults. It also includes:
<ul data-start="1547" data-end="1718">
<li data-section-id="1fxasr7" data-start="1547" data-end="1560">Overloads</li>
<li data-section-id="r8z0tm" data-start="1561" data-end="1589">Mid-range fault currents</li>
<li data-section-id="1lm5e88" data-start="1590" data-end="1612">Transformer inrush</li>
<li data-section-id="1gunpqi" data-start="1613" data-end="1639">Motor starting current</li>
<li data-section-id="4bxgkp" data-start="1640" data-end="1718">The actual available fault current at the point of installation/connection</li>
</ul>
 
That is why coordination studies often include not only protective-device curves, but also transformer damage curves, conductor damage curves, and inrush points.

<h2 data-section-id="115fkky" data-start="1888" data-end="1938">Role of Fuse Systems in Selective Coordination</h2>
Fuse systems are often easier to coordinate when the proper current-limiting fuse families are used.
With modern current-limiting fuses, coordination can often be achieved using published selectivity ratios and time-current data, rather than relying only on assumptions from nameplate ratings.
 
<h3>Where OptiFuse Fits In</h3>
Industrial fuse selection plays an important role in achieving selective coordination in electrical systems. Engineers rely on available time-current data and fuse characteristics to evaluate how different fuse families behave under overload and fault conditions.
OptiFuse provides industrial fuse families commonly used in coordination-sensitive designs, including current-limiting Class CC (<a href="https://www.optifuse.com/fuses/industrial-and-ul-fuses-63/293/">FPK</a> / <a href="https://www.optifuse.com/fuses/industrial-and-ul-fuses-63/295/">TPK</a>), Class J (<a href="https://www.optifuse.com/fuses/industrial-and-ul-fuses-63/523/">T6J</a>), and Class T (<a href="https://www.optifuse.com/fuses/industrial-and-ul-fuses-63/495/">F3T</a> / <a href="https://www.optifuse.com/fuses/industrial-and-ul-fuses-63/496/">F6T</a>) products. Each fuse class offers different performance characteristics in terms of time delay, current limitation, and interrupting capacity, which can be evaluated during coordination studies.
For example, Class J time-delay fuses such as the T6J series provide published time-current curves and let-through data that can be used when comparing upstream and downstream device behavior. Class CC fuses are often used in branch circuit applications where compact size and current limitation are key considerations, while Class T fuses are commonly applied in feeder and service entrance protection where high interrupting ratings are required.
In selective coordination studies, this type of published performance data allows engineers to compare device behavior using consistent technical criteria rather than relying solely on nameplate ratings. This supports more predictable coordination analysis when evaluating system protection strategies.

Selective Coordination Ratios Between Class J and Class T Fuses
<img decoding="async" src="http://cms.optifuse.com/uploads/2026/05/Screenshot-2026-05-19-at-7.12.57 AM.png" alt="Class J and class T" />
Selective coordination ratios provide a quick starting point for matching upstream and downstream fuses. In this table, a 2:1 ratio means the line-side fuse should be at least twice the amp rating of the load-side fuse, while a 3:1 ratio means it should be at least three times the amp rating.
These ratios help designers quickly identify Class J and Class T fuse combinations that are more likely to isolate a fault at the load side without opening the upstream device.

Final coordination should still be verified against time-current curves, available fault current, and the specific application requirements. See our <a href="https://www.optifuse.com/blog/optifuse-fuse-selection-guide/" target="_blank" rel="noopener">Fuse Selection Guide </a>for complete context. For application support or fuse selection help, contact OptiFuse at <a href="mailto:sales@optifuse.com">sales@optifuse.com</a>

Selective Coordination in Electrical Systems: Time-Current Curves and Fuse Selection

Understand selective coordination in electrical systems, including NEC concepts, time-current curves, and how current-limiting fuses help isolate faults and improve uptime.

Selective Coordination: What It Is, Why It Matters, and How to Apply It

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When a circuit needs to open quickly during an overload or short circuit, a fast-acting fuse usually makes more sense than a time-delay design.The OptiFuse <a href="https://www.optifuse.com/fuses/electronic-glass-ceramic-fuses-39/254/">FSC / FSC-P</a> is a 5 x 20 mm fast-acting glass fuse rated 250VAC and available from 125mA to 20A. OptiFuse offers the FSC with or without axial leads, and its clear glass body allows for visual inspection of the filament. The fuse is UL Listed and commonly used in applications sensitive to changes in the flow of current.

This is the flip side of the time-delay fuse conversation. If a circuit does not have a large, normal startup surge, designers often want the fuse to react quickly when current rises beyond normal limits. OptiFuse’s <a href="https://www.optifuse.com/blog/choose-a-tube-fuse/">tube-fuse selection guide</a> explains that time-delay fuses are better suited for circuits with temporary overloads or transient current, which means fast-acting fuses are often the better fit when that ride-through is not needed.
In practical terms, that makes fast-acting protection a strong fit for sensitive electronic circuits, appliance controls, and other loads where a fault should be cleared quickly instead of being allowed to ride through for extra time.

A few details make the FSC line easy to apply:
<ul>
<li>5 x 20 mm glass tube fuse</li>
<li>Fast-acting characteristic</li>
<li>250VAC rating</li>
<li>Available in cartridge and axial-lead versions</li>
<li>Clear body for quick visual inspection</li>
<li>Designed for circuits sensitive to changes in current flow</li>
<li>125mA to 20A</li>
<li>200A AC interrupting rating</li>
</ul>

One of the strengths of the FSC family is its flexibility across several mounting styles, depending on how the equipment is built.

For more inquiries, contact OptiFuse at <a href="mailto:sales@optifuse.com">sales@optifuse.com</a>. <a href="https://www.optifuse.com/blog/optifuse-fuse-selection-guide/">See our Fuse Selection Guide for complete context</a>.

Precision Protection for Sensitive Electronics with the FSC Fuse

Learn when to use the OptiFuse FSC fuse, where fast-acting protection makes sense, and how this 5 × 20 mm glass fuse fits sensitive circuits, appliances, and electronic design

FSC Fuse: A Simple Solution for Sensitive Electronic Circuits

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If your circuit has a harmless inrush: motor start, transformer magnetizing current, capacitor charging, or an alternator kick: fast-acting fuses can become a nuisance. OptiFuse <a href="https://www.optifuse.com/fuses/electronic-glass-ceramic-fuses-39/257/">TSC</a> is a 5x20 mm time-lag (slow-blow) glass fuse designed to ride through brief surges and open only when an overcurrent actually persists.

TSC is a 20mm long x 5mm diameter glass cartridge fuse, offered with (TSC-P) or without (TSC) axial leads, and UL listed.
Time-lag behavior is the entire value proposition: it helps prevent nuisance openings in circuits that legitimately draw a short inrush above steady-state current.

<ul>
<li>Size: 5x20mm (ULxCSA)</li>
<li>Characteristic: Time lag (slow-blow)</li>
<li>Voltage rating: 250VAC</li>
<li>Current range: 100mA to 15A</li>
<li>Interrupt rating: 200A AC</li>
<li>Visual inspection: clear glass body supports quick filament checks</li>
<li>Bonus (packaging): Select items available in blister packs.</li>
</ul>

In practice, it’s a strong fit for:
<ul>
<li>Small motors/fans/pumps</li>
<li>Transformers and power supplies</li>
<li>Cap-input loads (brief charging surge)</li>
<li>Industrial control and general electronics needing serviceable 5x20mm protection</li>
</ul>

A good fuse choice can still fail in the field if the mounting method is sloppy. With 5x20mm fuses, you generally have two clean paths: in-line holders for harness installs, or board-mount / solderable solutions for electronics.
 
In-line holders for harness installs
OptiFuse offers compatible 5x20mm in-line holders when you want the fuse in the wiring harness:
<ul>
<li><a href="https://www.optifuse.com/fuse-holders-blocks-and-accessories/electronic-glass-ceramic-fuses-14/in-line-fuse-holder-15/89/">LPC-02</a> (10A, 500VAC / 32VDC)</li>
<li><a href="https://www.optifuse.com/fuse-holders-blocks-and-accessories/electronic-glass-ceramic-fuses-14/in-line-fuse-holder-15/90/">LPC-08</a> (10A, 32VDC)</li>
<li><a href="https://www.optifuse.com/fuse-holders-blocks-and-accessories/electronic-glass-ceramic-fuses-14/in-line-fuse-holder-15/92/">LPC-24</a> &#8211; UL certified (30A, 250VAC / 32VDC)</li>
</ul>
These are the go-to when you want the fuse accessible without opening the enclosure or when protection needs to be placed close to the source.
 
Solderable / PCB-friendly mounting
If you need a fuse on a PCB, there are two common approaches:
<ul>
<li>Use the leaded version (TSC-P)</li>
</ul>
The axial leads let you solder the fuse directly into the circuit, which is simple and compact. This is often used in cost-sensitive designs or where service access isn’t critical.
<ul>
<li>Use a PCB-capable fuse holder to keep it replaceable</li>
</ul>
Direct-solder fuses work, but they aren’t fun to replace. For a more robust, serviceable design, use a PCB/panel fuse holder so the fuse can be swapped without rework. A holder like <a href="https://www.optifuse.com/fuse-holders-blocks-and-accessories/electronic-glass-ceramic-fuses-14/fuse-clip-19/153/">CSC-05</a> keeps the circuit serviceable while still letting you solder the holder leads/pins to the board.

If you need a different time-current behavior or body material, OptiFuse offers additional tube fuse counterparts:
<ul>
<li><a href="https://www.optifuse.com/fuses/electronic-glass-ceramic-fuses-39/258/">TCC</a> (ceramic, time lag)</li>
<li><a href="https://www.optifuse.com/fuses/electronic-glass-ceramic-fuses-39/256/">MSC</a>  (glass, medium time lag)</li>
<li><a href="https://www.optifuse.com/fuses/electronic-glass-ceramic-fuses-39/254/">FSC</a> (glass, fast acting)</li>
</ul>
For more information, read our <a href="https://www.optifuse.com/blog/choose-a-tube-fuse/">How to Choose a Tube Fuse</a> blog.
For more inquiries, contact OptiFuse at <a href="mailto:sales@optifuse.com">sales@optifuse.com</a> and <a href="https://www.optifuse.com/blog/optifuse-fuse-selection-guide/">see our Fuse Selection Guide for complete context</a>.

Built for Inrush: The TSC 5x20mm Time-Lag Glass Fuse

OptiFuse TSC / TSC-P is a 5x20mm time-lag glass tube fuse rated 250VAC with a 200A interrupt rating. Built to tolerate inrush from motors, transformers, and power supplies; available with or without leads.

TSC 5x20mm Time-Lag Glass Fuse: 250VAC, 100mA-15A (UL/CSA)

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