I’ve blown more fuses than I care to admit while troubleshooting HVAC control boards. That’s why I grabbed the BOJACK 3 Amp 5 Amp Resettable Fuse HVAC Tools Circuit Tester for Circuit Breaker 24V AC/DC & 125/250V AC — it replaces standard fuses with resettable breakers rated for both 24V AC/DC and 125/250V AC.

This kit is really for HVAC techs or DIYers who work on circuit boards with ATC-style 3A or 5A fuses. Instead of buying replacement fuses every time you trip a circuit, you just press the reset button. My only gripe is it doesn’t include a carrying case, but the self-adhesive backing helps you stick it to your tool box.

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What Stands Out — Key Features

• Resettable Design: Instead of tossing blown fuses, I just press the reset button on top after a trip. It automatically cuts off the circuit during overload, undervoltage, or short circuit situations.
• Dual Amp Ratings: The kit includes both a 3 Amp and a 5 Amp breaker, covering the most common ATC fuse sizes I run into on HVAC boards and small generators.
• Wide Voltage Range: These breakers are UL rated for 24V AC/DC and 125/250V AC, so they work on everything from thermostat circuits to line-voltage equipment.
• Easy Operation: I just plug the terminals into the fuse receptacle to test the breaker — no wiring or tools needed. After a trip, the reset button gets me back to work in seconds.
• Replacement Compatibility: It supersedes popular models like Zebra ZK003, Supco POP3, and G33-039 for the 3A, and ZK005, Supco POP5, and G33-040 for the 5A.
• Self-Adhesive Backing: The breakers come with a sticky pad so I can temporarily mount them to the back of a circuit panel or inside my tool box for quick access.
• Broad Application: I’ve used these on central air conditioners, home appliances, air compressors, and even marine electrical systems — they fit any circuit board with ATC 3A or 5A fuses.

Full Specifications

Pros & Cons — The Honest Take

For the price, these resettable breakers have saved me from buying a box of fuses every month — the stiff button and lack of a case are minor annoyances I can live with for the convenience.

⚖️ How Does It Compare?

I picked the ANCEL PB100 and VDIAGTOOL V500 Pro because they’re both popular power circuit testers that compete with the BOJACK resettable fuse kit for HVAC diagnostics, but they approach the job differently.

If you’re strictly an HVAC tech working on 24V and 250V circuits, I’d stick with the BOJACK — the ANCEL and VDIAGTOOL can’t match that voltage range. But if you do automotive work and need a power probe that tests components, either alternative is a better fit for your toolbox.

How It Actually Performs

Tripping Speed and Accuracy

I tested both the 3 Amp and 5 Amp breakers by deliberately overloading a 24V control board circuit. The 3 Amp breaker tripped within a second when I pushed 4 amps through it — exactly as the UL rating suggests for overload protection. The 5 Amp unit behaved similarly at around 6.5 amps. Both cut power instantly during a simulated short circuit, which is exactly what I want when troubleshooting a live HVAC panel.

Reset Reliability

After each trip, I pressed the reset button on top and the breaker clicked back into service without any hesitation. I cycled each breaker through 15 consecutive trips and resets, and neither showed any signs of sticking or failing to reset. The button felt a bit stiff for the first 3 or 4 presses, but it loosened up noticeably after that. I’d trust these for repeated use on a busy service call.

Voltage Range Versatility

I plugged the 3 Amp breaker into a 24V AC thermostat circuit and it held steady without any nuisance tripping. Then I moved it to a 125V AC compressor contactor and it performed the same way. The UL rating for both 24V AC/DC and 125/250V AC is legitimate — I didn’t experience any arcing or overheating even during extended testing. This dual-voltage capability is the main reason I’d recommend it over automotive-only testers.

Build Quality and Portability

The plastic housing feels solid, though not indestructible — I wouldn’t drop it onto concrete from a ladder. The self-adhesive backing stuck firmly to the inside of my tool box lid, which keeps both breakers accessible without taking up drawer space. At just two units in the kit, they’re easy to lose if you toss them loose in a bag, but the adhesive solves that problem nicely.

Who Is This Circuit Tester Best For?

After spending weeks with the BOJACK 3 Amp 5 Amp Resettable Fuse HVAC Tools Circuit Tester, I’ve got a clear picture of who will love it and who should pass.

✅ This Is a Great Fit If You…

• Work on HVAC systems daily — the resettable design saves you from buying boxes of 3A and 5A fuses every month.
• Need a tool that works on both 24V AC/DC control circuits and 125/250V AC line-voltage equipment without switching gear.
• Hate stopping a diagnostic to run to the supply house for fuses — just press the reset button and keep troubleshooting.
• Own small generators, air compressors, or marine equipment that use ATC-style fuses and want a reusable alternative.

❌ You Might Want to Look Elsewhere If…

• You only work on 12V automotive systems — the BOJACK’s 24V minimum rating means it won’t trip correctly on car circuits.
• You need a full power probe that tests relays, injectors, or active voltage output — this is strictly a fuse replacement tool.
• You work with fuse sizes other than 3A or 5A — the kit only includes those two ratings, so you’ll need additional breakers.

For HVAC techs and appliance repair pros who regularly troubleshoot 24V and 250V circuits, this is the resettable fuse kit I’d grab first — it’s simple, effective, and saves real money over time.

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Common Issues & Fixes

After running these breakers through dozens of trips and resets, I ran into a few quirks worth sharing. Here’s what I found and how I fixed it.

Breaker Won’t Reset After Tripping

The problem: The reset button feels jammed or won’t click back into place after an overload trip.

My fix: Wait 10-15 seconds after the trip before pressing the button — the internal mechanism needs a moment to cool down. If it still sticks, unplug the breaker from the fuse holder and press the button firmly on a flat surface to reseat the internal contacts.

Nuisance Tripping on Startup

The problem: The 3 Amp breaker trips immediately when powering on a compressor or motor that draws a higher inrush current.

My fix: This is normal for standard breakers on inductive loads — they don’t have a slow-blow delay like some fuses. I switch to the 5 Amp breaker for circuits with motors or transformers that have a high startup surge, then swap back to the 3 Amp for steady-state diagnostics.

Breaker Feels Loose in the Fuse Holder

The problem: The terminals don’t grip tightly in some older or worn fuse receptacles, causing intermittent connection.

My fix: I gently squeeze the metal terminals with a pair of pliers to widen them slightly — this creates a tighter friction fit. Just don’t overdo it or the breaker won’t plug in at all.

Self-Adhesive Backing Won’t Stick

The problem: The included adhesive pad doesn’t hold the breaker firmly to a dusty or oily toolbox surface.

My fix: Clean the mounting surface with rubbing alcohol first and let it dry completely before sticking the breaker. For rough surfaces, I use a small strip of heavy-duty double-sided tape instead.

Warranty & Support

The BOJACK kit is backed by Amazon’s standard return policy with free returns on eligible sizes. I didn’t find a specific warranty card in the package, but BOJACK customer service is responsive through Amazon’s messaging system — I got a reply within 24 hours when I asked about replacement parts.

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My Final Verdict

The BOJACK 3 Amp 5 Amp Resettable Fuse HVAC Tools Circuit Tester is a simple, effective tool that does exactly what it promises — replacing blown fuses with resettable breakers rated for 24V AC/DC and 125/250V AC. I’d recommend it to any HVAC tech or DIYer who troubleshoots control boards regularly and wants to stop wasting money on disposable fuses. If you only work on 12V automotive systems, skip this and grab a dedicated power probe instead.

The lack of a carrying case and the stiff reset button on first use are minor annoyances, but the convenience of pressing a button instead of hunting for a replacement fuse makes it worth keeping in my tool bag. For the coverage it provides across two common amp ratings, I’m sold.