Five RXEF110 resettable PTC fuses, yellow discs with straight leads, three showing the X110 marking

RXEF110 Resettable PTC Fuse - 1.1A Hold, 72V Radial Polyfuse

$1.19 NZD
each Save 10% at 10+
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Five RXEF110 resettable PTC fuses, yellow discs with straight leads, three showing the X110 marking
  • Five RXEF110 resettable PTC fuses, yellow discs with straight leads, three showing the X110 marking
  • Single RXEF110 PTC fuse seen from above, X110 marking and two parallel tin-plated leads
  • RXEF110 fuse dimensions: 12.8 mm maximum body width and 5.05 mm lead spacing
RXEF110 Resettable PTC Fuse - 1.1A Hold, 72V Radial Polyfuse
SKU: FUSE-PTC-RXEF110

RXEF110 Resettable PTC Fuse - 1.1A Hold, 72V Radial Polyfuse

$1.19 NZD
Order before 7:30am for same-day dispatch 7-day dispatch, excluding public holidays

NZ Post: 1-2 days urban · 2-4 days rural

Shipping from $5.99 urban / $9.99 rural.

Buy more, pay less Prices shown are per unit. Add enough of this item and the lower rate applies on its own at checkout. There is no code to enter and you do not need to buy a pack. Choosing a tier here just sets the quantity for you. Larger quantities go out in the same bag, so packing, handling and postage cost us less per unit. We pass that saving straight on to you, so you can buy more for less.

Minimum order quantity: 5

Easy 30-day returns · 12-month warranty

Free Urban delivery on orders over $66
Urban $66 Rural $88

The Littelfuse RXEF110 is a resettable PTC fuse, often called a polyfuse, for low-voltage DC and AC circuits up to 72V. It carries 1.1A continuously at 20°C and trips at 2.2A or more, limiting the current to a trickle until the fault is cleared. Once power is removed and it cools, it resets by itself, so a short on a 12V or 24V project, a motor stall or a wiring mistake does not leave you hunting for a spare fuse.

Specifications

Part numberLittelfuse PolySwitch RXEF110, marked X110
TypeResettable PPTC fuse, radial leaded, not polarised
Hold current1.10A at 20°C (0.89A at 40°C, 0.69A at 60°C)
Trip current2.20A at 20°C
Maximum voltage72V DC or 72V AC rms
Maximum fault current40A at rated voltage
Time to trip8.2 seconds maximum at 5.5A, 20°C
Resistance0.15 to 0.25 ohm new, up to 0.38 ohm one hour after a trip
Power while tripped1.5W typical
Operating temperature-40°C to 85°C
Body12.8mm wide and 3.0mm thick maximum, flame-retardant epoxy (UL94 V-0)
Leads2 tin-plated copper, 0.81mm (20 AWG), about 5mm spacing
Full technical datasheet, derating table and dimensions PDF

What's in the box

5+
RXEF110 resettable fuses

Sold per fuse with a minimum of 5. You receive the quantity you order, loose in a clear bag.

Great for

Protecting the 12V feed to an LED strip or fan
Short-circuit protection on a breadboard power rail
Fusing a small DC motor or pump circuit
Guarding a 5V USB-powered Arduino or ESP32 build
Sensor, alarm and control wiring up to 24V
Protecting the output of a small 24V power supply

Wiring & getting started

  1. Check the size

    Your circuit's normal current must stay below the hold current at the hottest temperature the fuse will sit in: 1.1A at 20°C, 0.89A at 40°C, 0.69A at 60°C. A fault needs to draw 2.2A or more to trip it.

  2. Wire it in series

    Fit it in the positive supply line, as close to the power source as you can. Either lead can go to the supply side.

  3. Solder by hand

    The leads take normal hand or wave soldering. Keep it out of reflow ovens and away from hot parts, as extra heat lowers the current it will hold.

  4. Resetting after a trip

    A tripped fuse runs warm and passes only a small current. Remove the power or clear the fault, let it cool and it is ready to use again.

Note: For low-voltage circuits only. Never use it on 230V mains wiring, and keep the possible short-circuit current at or below 40A.

Frequently Asked Questions

Answers to the questions buyers ask most.

How is this different from a glass or blade fuse?
A glass fuse melts and has to be replaced. This one heats up when the current gets too high and switches to a high resistance, cutting the current to a small trickle. Remove the power or clear the fault, let it cool, and it works again. The trade-off is speed: it reacts more slowly than a fast-blow glass fuse, so it suits protecting wiring and supplies rather than delicate electronics that need instant cut-off.
What current can I run through it?
Up to 1.1A continuously at 20°C. It holds less when it is warm: 0.89A at 40°C and 0.69A at 60°C, so size it for the hottest place it will sit, such as inside an enclosure. It trips at 2.2A or more.
How fast does it trip?
It depends on how big the fault is. At 5.5A it trips within 8.2 seconds at 20°C, and a hard short trips it faster. A fault only just over 2.2A can take much longer, which is normal for a PTC fuse.
Can I use it on 12V or 24V?
Yes. It is rated for up to 72V DC or 72V AC rms, so 5V, 12V, 24V and 48V circuits are all fine. The possible short-circuit current must stay at or below 40A.
Can I use it on mains power?
No. It is for low-voltage circuits up to 72V only. Never use it on 230V mains wiring.
Which way round does it go?
Either way. It is not polarised. Wire it in series with the positive supply, as close to the power source as you can.
Does it drop much voltage?
Very little. A new fuse measures 0.15 to 0.25 ohm, so at 1A it drops about 0.15 to 0.25V. After a trip the resistance is a little higher, up to 0.38 ohm an hour later.

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