Mersen Tri-Onic TR-R Class RK5...
IN STOCK (leaves warehouse same day if ordered before 3pm ET)
$26.91
Mersen Tri-Onic TR-R Class RK5 Time-Delay Fuse

Mersen Tri-Onic TR-R Class RK5 Time-Delay Fuse

(No reviews yet) Write a Review

Model: TR12R

In Stock (leaves warehouse same day if ordered before 3pm ET)

$26.91
Adding to cart… The item has been added
Free Shipping on orders over $199
We price match and offer bulk discounts! Click Add to Quote. It's quick and easy.
✨
Earn points with this purchase! You can redeem points for giftcards, iPads, XBox's and more. View Rewards
Free Keying on all locks
You may also like

Mersen TR12R Tri-Onic Class RK5 Time-Delay Fuse, 12A

The Mersen TR12R is a Tri-Onic series Class RK5 time-delay fuse rated 12A for 250VAC / 160VDC applications, built with ferrule terminals for clip-mount installation in fuse blocks and holders. Designed for AC/DC circuit protection, this fuse combines a durable PolyTube insulating body with copper connection terminals to deliver dependable overcurrent protection in demanding electrical environments. With a 200 kA AC maximum interrupting rating and RoHS-compliant construction, the TR12R is engineered for reliable, code-compliant performance in motor, control, and branch circuit applications.

Key Features

  • Ampere & Voltage Rating: 12A rated for 250VAC / 160VDC, suitable for AC/DC circuit protection.
  • Time-Delay Class RK5: Time-delay speed characteristic allows the fuse to ride through momentary inrush currents while still protecting against sustained overloads.
  • High Interrupting Capacity: 200 kA AC maximum breaking capacity (I1) for dependable protection against high fault currents.
  • Copper Connection Terminals: Copper terminal material ensures a reliable, low-resistance connection at the ferrule contacts.
  • Durable PolyTube Body: PolyTube insulating body material provides sturdy, non-conductive housing for the fuse element.
  • Clip Mounting, Ferrule Style: Ferrule-terminal Tri-Onic construction is designed for clip-style mounting in standard fuse holders and blocks.
  • Frequency Rating: Rated for 50/60 Hz, compatible with standard AC power systems.
  • Compact Footprint: Measures 2 in in length and weighs just 0.037 lb.

Certifications & Compliance

  • RoHS Compliant
  • UL-Recognized Voltage Ratings: 250VAC / 160VDC

Technical Specifications

  • Ac Max I R Breaking Capacity I1: 200 kA
  • Ac Or Dc: AC/DC
  • Body Insulating Material: PolyTube
  • Connection Terminal Material: Copper
  • Frequency Hz: 50/60 Hz
  • Mounting Method: Clip
  • Product Length: 2 in
  • Product Weight: 0.037 lb
  • Rated Voltage Ac Ul: 250 V
  • Rated Voltage Dc Ul: 160 V
  • Rohs Compliant: Yes
  • Speed Characteristic: Time Delay

Typical Applications

  • Motor and Control Circuit Protection
  • Industrial and Commercial Panelboards
  • Branch Circuit and Equipment Protection
  • OEM and Panel Builder Fuse Assemblies
  • AC/DC Rated Electrical Systems

Why Mersen?

Mersen's Tri-Onic TR12R combines a Class RK5 time-delay design with a 200 kA interrupting rating, copper terminals, and a durable PolyTube body to deliver consistent, code-compliant overcurrent protection. RoHS-compliant construction and dual AC/DC voltage ratings make this fuse a dependable choice for professional electrical and industrial installations that demand reliable circuit protection.

Manufacturer Resources

Mersen Product Catalog

Product Specs

Product Group:
Circuit Protection
Rohs Compliant:
Yes
Body/Insulating Material:
PolyTube
Frequency (Hz):
50/60 Hz
AC Max I.R./Breaking Capacity: I1:
200 kA
Fuse Class:
Class RK5
Speed/Characteristic:
Time Delay
AC or DC:
AC/DC
Rated voltage AC UL:
250 V
Department:
Electrical
Mounting Method:
Clip
Product Type:
Time-Delay Fuse
Product Subgroup:
Fuses

Mersen TR12R – Frequently Asked Questions

1) Will a Mersen Tri-Onic TR-R fuse hold in on motor starting inrush without blowing?
That is what the time-delay element is for. The Tri-Onic TR-R is a Class RK5 time-delay fuse, so it rides through the momentary inrush of a motor start or transformer energization and still opens on a sustained overload. It is the normal choice for motor branch and control circuit protection. If you need a fast-acting fuse for a purely resistive or electronic load instead, look at a fast-acting midget type such as the Littelfuse BLF Series.
2) Can I use the Mersen TR-R fuse on a DC circuit as well as AC?
Yes, it is rated AC/DC. The UL voltage ratings are 250V AC and 160V DC, at 50/60 Hz on the AC side. Do not apply it above 160V on a DC bus.
3) Can I drop a Class RK5 fuse into a holder that currently has Class H or K fuses?
Yes. Class RK5 fuses are dimensionally interchangeable with Class H and Class K fuses of the same ampere and voltage rating, which is the whole point of the R class: you gain current limiting and a 200 kA interrupting rating in an existing 250V holder. The reverse is not true if the holder has rejection clips, which only accept R-class fuses.
4) Will the Mersen TR-R work on a 480V or 600V circuit?
No. The TR-R is rated 250V AC, so it is limited to 120V, 208V, and 240V systems. For a 480V or 600V feeder you need a 600V class fuse instead.
5) What is the difference between the Mersen Tri-Onic TR-R fuse and the Littelfuse CCMR040 Class CC time-delay fuse?
Both are time-delay fuses, but they are different fuse classes and are not interchangeable in the same holder. The Mersen Tri-Onic TR-R is a Class RK5 time-delay fuse rated 250VAC with a clip mounting method and ferrule terminals, offered in 12A and 125A. The Littelfuse CCMR040 is a CCMR series Class CC time-delay fuse rated 40A. Class CC fuses use a rejection-style body and mount in Class CC holders, while Class RK5 ferrule fuses seat in standard RK/H-class clips, so verify which holder is in the panel before ordering.
6) I need a fuse for a 600V metering circuit - will the Mersen Tri-Onic TR-R work?
No. The Mersen Tri-Onic TR-R carries a 250VAC UL rated voltage, so it should not be applied on a 600V circuit. For metering duty at that level, the Square D PowerLogic energy meter fuse pack is a set of three 0.5A 600V fuses intended for PowerLogic energy meter circuits. Match the fuse voltage rating to the system voltage rather than derating by assumption.
7) What amperage ratings does the Mersen Tri-Onic TR-R come in?
Two ratings are offered: 12A (part number TR12R) and 125A (TR125R). Order by the MPN so you get the right ferrule size for your block, since the physical size of an RK5 changes with the ampere class.
8) Is a 200 kA interrupting rating enough for my industrial panel?
The Tri-Onic TR-R carries a 200 kA AC maximum breaking capacity, which is the top of the range for current-limiting branch fuses and covers available fault current at essentially any commercial or industrial service. Check the fault current calculated at your panel against that number and you will not be short.
9) How does the Mersen TR-R mount, and do I need a fuse block?
It is a ferrule-style fuse with copper terminals and clip mounting, so it drops into standard fuse clips, blocks, or a fused disconnect. The fuse block or holder is separate and is not included.
10) Is a Littelfuse AGU or AGA glass fuse an alternative to the Mersen Tri-Onic TR-R?
They serve different jobs. The Littelfuse AGU is an AG-series glass tube fuse and the Littelfuse AGA5 is a 5A AGA series glass fuse, both small glass-body automotive and electronics style fuses. The Mersen Tri-Onic TR-R is a Class RK5 time-delay branch circuit fuse with a PolyTube insulating body, copper terminals, 250VAC rating and a 200 kA AC interrupting rating for panelboard and motor circuit protection. Use the TR-R where a branch circuit or motor starter calls for an RK5 fuse; glass fuses are not a substitute in that duty.
11) Is the Mersen Tri-Onic fuse body plastic or glass, and does it meet RoHS?
The body is PolyTube, a solid insulating tube rather than glass, so it holds up better to handling and heat in a panel than a glass tube fuse like the Littelfuse AGU or AGA series. Construction is RoHS compliant.
How fast can I get the Mersen TR12R delivered?
Most orders ship the same day from our distribution partners, with quick delivery throughout the continental U.S. Need it urgently? Contact Us for expedited shipping options.
Can I return it if it doesn’t work for me?
Yes—ZenSupply offers a hassle-free return policy. If the product isn’t the right fit, reach out to our support team for a return authorization or setup a return by following our return instructions.
Does the Mersen TR12R come with a warranty?
Absolutely. The Mersen TR12R is backed by a manufacturer’s warranty. For full warranty terms, check the product documentation or Contact Us.
How do I get technical support or installation help for the Mersen TR12R?
You can call, text, or email our expert support team for fast answers. We’re here to help with product selection, installation tips, and troubleshooting. Contact Us
Why buy the Mersen TR12R from ZenSupply?
ZenSupply makes it easy to get the commercial door hardware you need—fast shipping, expert support, and rewards on every order. Our team is always ready to help you choose the right product for your project.
!