Manual Reset DC Circuit Breaker 20A-300A Surface or Inline

Reset it in the field. No spare fuse required.

A fuse does its job exactly once. It goes somewhere out the back of the shed at nine at night, and now you are digging through the crib bag for a spare of the right rating — or you are running the circuit unprotected because you have not got one. Out on a station or three hours up a beach track, that is the difference between a five second job and a wasted day.

This is the resettable answer to that. It trips thermally when the current stays above the rating, you push the red lever back down, and the circuit is live again. Nothing to replace, nothing to carry, nothing to lose.

It comes in two bodies. Type A is a surface-mount block, 72 × 48 × 44 mm, with M6 studs under rubber boots and the rating moulded into the case — twelve ratings from 20A to 300A. Type B is an inline barrel, 95 mm long, with gold screw terminals and a flat mounting bracket — seven ratings from 30A to 125A. Both carry a manual reset lever and a second button that switches the circuit off by hand, so the breaker doubles as a local isolator.

One thing to be straight about before you size anything: the supplier prints the amp rating on the case and nothing else. There is no voltage rating, no interrupt capacity and no IP number anywhere on the product or in the supplier's own artwork. That matters, and it is set out plainly further down.

What It Does

Trips on overload: a thermal element opens the circuit when the current sits above the rating for long enough to heat it.
Resets by hand: push the red lever back down and the circuit is live again. There is no consumable and nothing to buy twice.
Switches off by hand: the second red button trips it deliberately, so you can kill one circuit without pulling a lead off a terminal.
Marks its own polarity: the Type A base is moulded AUX and LOAD, and one stud is marked To Battery, so it goes in the right way round without guesswork.
Bolts down flat: Type A through a 7 mm hole in its own foot, Type B on a 42.5 mm bracket — both onto a bulkhead, a battery box lid or a panel.
Covers a wide range: 20A through to 300A across the two bodies, so one part number handles a light circuit and a winch feed.

Key Features

Thermal trip: the supplier's own panel names the mechanism as a thermal trip, not a magnetic one.
Type A dimensions: 72 mm long, 48 mm wide, 44 mm high, with a 7 mm diameter mounting hole.
Type A terminals: M6 studs with hinged rubber covers over both, so nothing shorts across them in a battery box.
Type B dimensions: 95 mm overall length, 48 mm high, on a 42.5 mm mounting bracket.
Type B terminals: screw posts inside clear barrels, with a reducer sleeve supplied so it takes a smaller cable as well.
Rating moulded in: the amp figure is moulded into the Type A case and printed on the Type B lever, not stuck on with a label that falls off.
Ignition Protected moulding: those two words are moulded into the Type A housing. No standard number is printed alongside them — see the limits below.
Nineteen options: twelve Type A ratings and seven Type B ratings, sold one breaker per order.

What This Will Not Do

This is a protection device. If it is wrong for the job, the failure mode is a fire, so here is everything the supplier does not tell us.

It publishes no voltage rating: not on the case, not on any of the thirty-two supplier images. DC voltage is not a formality on a breaker — a DC arc has no zero crossing to help extinguish it, so a contact gap that clears a fault at 12V can hold an arc at 48V. Nothing here tells you which side of that line it sits on.
It publishes no interrupt capacity: a battery bank can shove several thousand amps into a dead short. The figure that says whether a breaker can open that safely is the interrupt capacity, and it is not stated. Treat this as unproven on a large bank.
It has no IP number: the word WATERPROOF is moulded into the Type A lid, and that is the whole of the evidence — no IP figure, no immersion depth, no duration. The Type B inline body carries no such marking at all. Take it as splash and weather resistance in a sheltered spot, not as something to sit under water.
It carries no compliance mark: there is no RCM, CE, UL or AS/NZS mark on the product or in the artwork, and no certificate was sighted. Ignition Protected is moulded on the Type A case, but no standard number — ISO 8846 or SAE J1171, the two that normally sit behind that phrase — is printed with it.
It publishes no trip curve: nothing states how long it holds an inrush before it opens, or how far above the rating it has to go. If you are sizing around a winch or a compressor start, that number is the one you need and we do not have it.
It is not a fuse: despite the word sitting in the product title, this is a resettable breaker. Where a fuse is specifically called for, this is not a swap for one.
It only watches current: it does nothing about reverse polarity, over-voltage, a lightning surge or a flat cell. Those want their own protection.

So: for a 12V or 24V vehicle, camper or small marine circuit, this is an ordinary resettable DC breaker doing an ordinary job, and the reset lever is the reason to have one. For a 48V bank, or any bank big enough to matter, pick a device that publishes both a maximum DC voltage and an interrupt capacity, and size the cable to match. Right tool for the job beats hoping.

What Else You'll Need

A breaker is one part of the run between a turbine, a controller and a battery bank. Here is the rest of it:

Off-grid wiring layout showing turbine and solar into a hybrid controller, then breaker, bus bar, battery bank and inverter

Bus bars: every breaker feeds from or into something. A proper bus bar stops four ring terminals stacking up on one battery post.
Anderson plugs: a plug on the turbine lead lets you unplug it to drop the tower for maintenance, instead of undoing terminals in the weather.
Flexible copper cable: the breaker protects the cable, so the cable has to be sized first. Run length, voltage and current all drive it.
Lugs and a crimper: an M6 stud wants a properly crimped lug on it. A twisted strand under a nut is where the heat starts.
A rotary disconnect: a dedicated isolator to shut the bank down by hand before you touch anything, separate from your overload protection.
The rest of the electrical range: bus bars, breakers, isolators, cable, lugs and plugs in one place.

Cable sizing depends on your own run length, voltage and current, and it is not something a product page can do for you. On a 12V or 24V build the currents are higher for the same load, so check the sizing against your own run or put it past your sparky.

Q & A

Is this a fuse or a circuit breaker?

A circuit breaker. The word "Fuse" in the title is wrong. It trips thermally and you reset it with the lever — there is no element to replace, and nothing about it is a one-shot fuse.

What DC voltage is it rated to?

Not specified by supplier. That is the honest answer and it is the most important thing on this page. No voltage appears on the case or in any of the thirty-two supplier images, so we will not print one. The product title says 12V 48V; nothing we can see supports the 48V end of that.

Will it protect a 48V battery bank?

We cannot say that it will. Without a stated maximum DC voltage and a stated interrupt capacity, there is no way to check it against a bank's fault current. For a 48V system, buy a breaker that publishes both figures and size it against your actual bank.

What is the difference between Type A and Type B?

Type A is the black surface-mount block with M6 studs, 20A to 300A. Type B is the inline barrel with screw terminals, 30A to 125A. Type A takes heavier cable and higher ratings; Type B sits in a lead rather than being bolted to a panel.

Is it actually waterproof?

No IP number is published, so we are not going to call it waterproof. WATERPROOF is moulded into the Type A lid and the stud covers are rubber, which reads as splash and weather protection. The Type B inline body carries no such marking. Do not mount either where it will be submerged.

Can I use it as an on-off switch?

The second red button trips it by hand, so yes for occasional isolation of one circuit. It is not built as a daily-use switch and it is not a substitute for a proper battery isolator on the main bank.

Which stud goes to the battery?

On Type A the supplier labels one stud To Battery and moulds AUX and LOAD into the base. Wire the supply side to the battery stud and the circuit you are protecting to the load side.

Specs

Specification	Detail
Device type	Resettable thermal circuit breaker, manual reset — not a fuse
Ratings, Type A (surface mount)	20, 30, 40, 50, 60, 80, 100, 120, 150, 200, 250 and 300 A
Ratings, Type B (inline)	30, 40, 50, 60, 80, 100 and 125 A
Maximum DC voltage	Not specified by supplier — no voltage is printed on the product or shown in any supplier image
Interrupt capacity (AIC)	Not specified by supplier
Trip curve or time delay	Not specified by supplier
Trip mechanism	Thermal, per the supplier's own feature panel
Reset	Manual lever. A separate button trips the circuit off by hand
Type A dimensions	72 × 48 × 44 mm (length × width × height)
Type A terminals	M6 studs with hinged rubber covers. Base moulded AUX and LOAD; one stud marked To Battery
Type A mounting hole	7 mm diameter
Type B dimensions	95 mm long, 48 mm high, 42.5 mm mounting bracket
Type B terminals	Screw posts in clear barrels, reducer sleeve supplied
Type B cable range	Supplier prints AWG 3–15 with the reducer sleeve and AWG 0–10 without it — roughly 1.7–27 mm² and 5.3–53 mm². No mm² figure is printed on the product
IP rating	Not specified by supplier — WATERPROOF is moulded on the Type A lid with no IP figure. Type B carries no such marking
Ignition protection	Ignition Protected is moulded on the Type A housing. No standard number (ISO 8846 or SAE J1171) is printed and no certificate was sighted
Compliance marks	None visible. No RCM, CE, UL or AS/NZS mark appears on the product or in the supplier artwork
Operating temperature	Not specified by supplier
Housing material	Not specified by supplier
Weight	Not specified by supplier
Supplier stated uses	Car audio and video, boats, trucks, buses, motorhomes, quad bike winches and marine DC circuits
Pack quantity	One breaker
Delivery	10–14 days from the day you order, allow up to 3 weeks. Free to Australia and New Zealand

Watch Me

No video on this one. If you are wiring an off-grid system, these two guides are worth reading first:

How to install and start up a wind turbine: the correct sequence, and the shock hazards to know about before you start.
Turbine spinning but showing 0W: a tripped breaker or an open isolator is one of the first things to check when the numbers do not add up.

One gap in the supplier's photographs is worth knowing about. Every rating from 30A to 300A is pictured on the surface-mount body, and every rating from 20A to 125A is pictured on the inline body. The 20A appears only as an inline unit, and there is no photograph of a 20A surface-mount breaker anywhere in the set, so the artwork does not confirm what a Type A 20A physically looks like.

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Wind Turbine FAQs

Start with two questions: how much wind does your site actually get, and how much room do you have.
Vertical turbines (X-300, T-500W, and the H12 and HPRO series) start turning in about 2 m/s and take wind from any direction, so they suit rooftops, suburban blocks and anywhere the wind swirls and shifts. They run from 300 W up to 2000 W.
Horizontal turbines (S-400W, M-600W, M-800W, and the L1, L2 and G series) want cleaner, steadier wind and a clear run at it. They scale further — 400 W up to 5000 W — and most of them survive heavier weather.
Match the turbine to your battery bank, not to the biggest number. 12 V suits a camper, 4WD or tinnie; 24 V a van, cabin or boat; 48 V a shed or remote block. The largest models run at 220 V, and the L2-3000, G-3000 and G-5000 are ground-mount only — they need a 10–15 m mast and are not rooftop units.
Rated power is measured at 10–12 m/s. What you get at your place depends on your wind, your mast height and the season — not on a number on our website.
No.Wind turbines generate "wild" 3-phase AC power that changes voltage constantly with the wind speed. Connecting it directly to a battery or a standard solar inverter will instantly destroy your equipment. Youmustwire the turbine into a dedicatedWind/Solar Hybrid MPPT Controller with an integrated Dump Load Resistor. The controller converts the power to stable DC to charge your batteries safely.
You must match the turbine and its hybrid controller to the exact voltage of your existing battery bank:
- 12V: Best for compact mobile setups like caravans, 4WDs, and camper trailers.
- 24V: Great for medium-sized setups like off-grid sheds, cabins, and motorhomes.
- 48V: The gold standard for full off-grid home systems. Higher voltage means less energy loss through your wires and allows you to use thinner, safer cables.
When your battery bank becomes 100% fully charged, it stops accepting power. If a heavy wind storm hits at night when your batteries are full, a turbine with nowhere to send its power will "free-spin" out of control and physically fly apart. A hybrid controller fixes this by automatically diverting that excess power into the dump load resistor, which burns it off safely as heat and acts as an electronic brake to slow the turbine down.
No,that is the main benefit of the vertical design. Traditional horizontal "propeller" turbines create a high-pitched, annoying "chopping" noise. Our ST Tulip and Flower series utilise advanced omnidirectional maglev-style bearings, making them virtually silent and completely vibration-free, all you will hear is the wind. They are perfect for suburban blocks, tight caravan parks, and areas close to neighbours.
It will turn, but turning is not charging. The blades start rotating at about 1.5 m/s — a light breeze. Charging starts once the wind clears the cut-in speed of about 3.5 m/s, and output climbs from there — the rated figure is measured at 13 m/s (about 47 km/h). A gentle breeze keeps the turbine ticking over; it takes real wind to push real power into your batteries.
You should connect the wind turbine to a battery bank first, via a dedicated charge controller, rather than directly to an inverter. Connecting a wind turbine directly to a standard inverter will damage the equipment or cause the system to fail.
🔋 The Correct Wiring SequenceTo safely capture and use the power, your setup must follow this exact order:
1. Wind Turbine: Generates wild, fluctuating 3-phase AC power as wind speeds change.
2. Hybrid/Wind Charge Controller: Converts the unstable AC power into steady DC power. It also protects the turbine from over-speeding by applying an electronic brake during high winds.
3. Battery Bank (12V/24V/48V): Acts as a buffer to store the energy. It absorbs sudden power spikes from wind gusts and provides a steady source of energy.
4. Off-Grid Inverter: Connects to the battery, converting the stored DC battery power into standard AC power for your household appliances.
⚠️ Why You Cannot Skip the Battery
- Unstable Voltage: Wind speeds change second by second. Without a battery to absorb and smooth out these massive fluctuations, a direct-connect inverter would constantly turn off and error out.
- Turbine Destruction: When a battery is full or disconnected, a wind turbine loses its "load" (resistance). Without that resistance, the blades can spin out of control in high winds and physically destroy the unit. The charge controller uses the battery connection to safely dump excess power and slow the turbine down.
Wiring & Installation Requirement:This wind turbine generates 3-phase AC power andcannotbe connected directly to a battery, solar controller, or home inverter. To operate safely, it must run through a dedicatedWind/Solar Hybrid MPPT Controller with an integrated Dump Load Resistor. The dump load prevents the turbine from over-speeding and destroying itself in high winds once your batteries are fully charged.
It is almost always one of three common installation issues. Check them in order:
1. Your multimeter is set to DC (the most common mistake).
- The issue: measuring the three turbine wires with the meter set to DC volts.
- The reality: wind turbines generate 3-phase AC power directly from the stator.
- The fix: switch your multimeter to AC volts (V~). Testing these wires on a DC setting gives a false reading near zero.
2. The turbine is stalling because of a short.
- The issue: the blades turn heavily and slowly, or lock up.
- The reality: if any of the three AC output wires touch each other, or the controller’s internal braking diodes have short-circuited, it acts as a magnetic brake — the turbine can never spin fast enough to build voltage.
- The fix: completely disconnect the turbine from the controller. If it suddenly frees up and spins much faster, the problem is a short in the wiring or a faulty controller.
3. Voltage drop from thin cables.
- The issue: thin wire run a long way from the tower to the battery shed.
- The reality: thin solar or automotive cable over a long run (20 metres or more) loses the power as heat in the wire before it reaches the controller.
- The fix: use heavy cable between the mast and the controller on long runs — minimum 8 AWG, ideally 6 AWG.
Because the number on the box is a peak rating, not a promise. A turbine’s rated output is measured at a specific wind speed — for these models that is 13 m/s, about 47 km/h — and most sites see far less most of the time. Your display shows what the wind is delivering right now, so it will sit well below the rated figure and move second by second with the wind. That is physics, not a fault.
Where these turbines earn their keep is time: they keep charging through the night and through weather that shuts solar down. If the display shows 0 W while the blades are spinning, that is a different issue — see the 0 W question below.
Not necessarily — this is one of the most common questions we get, and it's rarely a faulty unit. It's usually a quick settings check, or (on a first-time install) how the wiring and start-up sequence were done. See our full Wind Turbine 0W Troubleshooting & Installation Guide for the complete walkthrough, or contact us and we'll help you sort it out.
Short answer: wire your bus bar and breakers before and after the controller, then power up in the right order — battery first, then solar, then wind. Getting the sequence right prevents almost all wiring issues, including the common “spinning but 0 W” problem.
Correct installation comes down to isolation and the right sequence:
- Fit a breaker before the controller (turbine/solar side) and after it (battery side), landing on a DC bus bar
- Keep the turbine-to-controller cable run to 2–10 metres to limit voltage drop
- Power up in this order: battery breaker first, then solar, then wind turbine last
See our full How to Install & Start Up guide for the complete step-by-step walkthrough and wiring diagram.

Wind Turbine FAQs

Manual Reset DC Circuit Breaker 20A-300A, Surface or Inline

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