Mersen TR-R Series Class RK5 T...
IN STOCK (leaves warehouse same day if ordered before 3pm ET)
$29.26
Mersen TR-R Series Class RK5 Time-Delay Fuse, 250VAC/250VDC

Mersen TR-R Series Class RK5 Time-Delay Fuse, 250VAC/250VDC

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Model: TR1R

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

$29.26
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Mersen TR5R Class RK5 Time-Delay Fuse, 5A 250VAC/160VDC, Copper Ferrule Terminal

The Mersen TR5R is a Class RK5 time-delay fuse rated 5A for both 250VAC and 160VDC applications, engineered for dependable overcurrent protection in professional electrical systems. Built with copper ferrule terminals and a durable PolyTube insulating body, this fuse delivers a 200 kA breaking capacity for reliable fault-current interruption. Its time-delay characteristic allows temporary overloads to pass while still protecting circuits and equipment against sustained overcurrent conditions, making it well suited to motor and inductive-load applications.

Key Features

  • Current Rating: 5A provides precise overcurrent protection for medium-load circuits and equipment applications.
  • Class RK5 Time-Delay: Allows temporary overloads while protecting against sustained overcurrent conditions, ideal for motor and inductive load applications.
  • Dual Voltage Rating: 250VAC/160VDC coverage offers versatile protection for both AC and DC systems.
  • 200 kA Breaking Capacity: High interrupting rating ensures reliable fault current interruption in demanding electrical environments.
  • Ferrule Terminal Design: Copper connection terminals provide secure, low-resistance connections for professional installations.
  • PolyTube Body Construction: Durable insulating material ensures reliable performance and electrical isolation.
  • Frequency Rating: Rated for 50/60 Hz systems with clip mounting for standard fuse holders.
  • RoHS Compliant: Meets environmental compliance standards for professional electrical applications.

Certifications & Compliance

  • RoHS Compliant

Technical Specifications

  • Rohs Compliant: Yes
  • Fuse Class: Class RK5
  • Ampere Rating: 5A
  • Rated Voltage AC UL: 250V
  • Rated Voltage DC UL: 160V
  • AC Max I R Breaking Capacity I1: 200 kA
  • Body Insulating Material: PolyTube
  • Connection Terminal Material: Copper
  • Connection Terminal Type: Ferrule
  • Frequency: 50/60 Hz
  • Mounting Method: Clip
  • Speed Characteristic: Time Delay
  • Product Length: 2 in
  • Product Weight: 0.037 lb

Typical Applications

  • Motor Control Centers and Starter Applications
  • Industrial Control Panels and Equipment Protection
  • HVAC System Overcurrent Protection
  • Commercial Electrical Distribution
  • Process Control and Automation Systems
  • Power Supply and Converter Protection
  • Instrumentation and Control Circuit Protection

Why Mersen?

Mersen TR5R fuses deliver professional-grade protection with RoHS compliance and proven Class RK5 time-delay characteristics for both AC and DC circuits. The copper ferrule terminals and PolyTube construction ensure reliable, low-resistance performance in demanding motor, HVAC, and industrial control applications, backed by Mersen's focus on dependable electrical protection.

Manufacturer Resources

Mersen Product Catalog

Product Specs

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

Mersen TR1R – Frequently Asked Questions

1) Will a Mersen TR-R fuse work on a 480V motor circuit?
No. The TR-R Series is rated 250VAC, so it can only be applied at 250 volts or less. Using it on a 480V feeder or motor circuit is a misapplication regardless of the amp rating. For a 480V circuit you need a 600V class fuse, not this one. The TR-R covers 250V AC/DC work: motor starters, control panels, HVAC disconnects, and 120/208 or 240V distribution.
2) Why does my motor blow a fast-acting fuse at startup but not a Mersen TR-R?
Motor inrush is the reason. The TR-R is a time-delay fuse, so it rides through the brief high current a motor draws on start while still opening on a sustained overload. A non-time-delay fuse of the same amp rating sees that inrush as a fault and clears. On motor and other inductive loads, time delay is what lets you size the fuse close to the running load instead of oversizing to survive starting.
3) Is a Class RK5 fuse a drop-in replacement for a Class RK1 or Class H fuse?
Dimensionally yes, electrically not always. Class R fuses share case dimensions by amp and voltage band, so an RK5 like the TR-R fits the same R-rated block an RK1 sits in, and a Class R fuse will drop into an older Class H or K holder. The reverse does not hold: the rejection feature on a Class R block keeps a Class H fuse out, which is the point of it. Where the difference matters is let-through. RK1 limits current harder than RK5, so if the panel schedule or an equipment label specifically calls for RK1 for component protection, substituting RK5 is not equivalent even though it bolts in.
4) Can a Square D PowerLogic energy meter fuse pack replace a TR-R series fuse in a motor circuit?
No. The Square D PowerLogic energy meter fuse pack is a set of three 0.5A 600V fuses intended to protect the voltage-sensing leads of a PowerLogic energy meter, where the load is a few milliamps of instrumentation. The Mersen TR-R series is a Class RK5 time-delay fuse rated 250VAC with a 200 kA breaking capacity, built to let motor inrush pass while still clearing a sustained overcurrent, and it is offered from 1A up to 500A. A 0.5A meter fuse would open on the first start of any motor, and its 600V rating does not make it a branch-circuit device. If you are fusing the metering CT or PT leads on a switchboard, use the PowerLogic pack; if you are fusing the motor or the panel itself, use the TR-R at the amperage the starter calls for.
5) My equipment needs a 600V fuse - will the Mersen TR-R work?
The Mersen TR-R series is rated 250VAC and is the right choice on 120V, 208V and 240V systems. Where the equipment nameplate calls for a 600V device, the TR-R rating does not cover it - the Square D PowerLogic energy meter fuse pack, for example, is a 0.5A 600V set, which shows how differently a 600V-rated part is applied. Check the system voltage on the panel schedule before ordering: for a 480V motor feeder or any 600V-class assembly, a 250V fuse is not the substitution, and for 240V and below the TR-R covers 1A through 500A on clip-mounted RK5 blocks.
6) What amp ratings does the Mersen TR-R fuse come in?
The TR-R runs from 1A up to 500A on a single ordering axis. The full ladder is 1, 2, 2.5, 3, 5, 6, 8, 15, 20, 25, 30, 40, 50, 70, 80, 90, 110, 150, 175, 200, 225, 250, 300, 350, 400 and 500 amps, ordered as TR1R through TR500R (the 2.5A is catalogued TR2-1/2R). One thing to plan for: an RK5 fuse block is sized by amp band, so a 30A holder takes the ferrule-style small cases and the larger ratings move to bolt or blade cases in their own blocks.
7) Can the Mersen TR-R be used on a DC circuit?
Yes, the TR-R is rated for both AC and DC service. On AC it carries 250V; the DC rating is lower, at 160V, so a 250VDC battery or drive bus is outside what this fuse is listed for. For 50/60 Hz AC work it is applied to the full 250V.
8) How does the Mersen TR-R fuse mount, and do I need a fuse block for it?
Clip mounting. The smaller ratings use copper ferrule ends that seat into spring clips in a Class R fuse block or a fused disconnect, so you need the block or switch that matches the amp band. Nothing bolts through on the ferrule sizes. Copper terminals keep contact resistance down, which matters in a starter enclosure where heat rise on the clips is what ages the connection.
9) Is a Mersen TR-R fuse the right choice for protecting a metering or instrumentation circuit?
Usually not the best fit. The TR-R is a time-delay power fuse built for motor and feeder duty, where inrush has to pass. A metering circuit or small control transformer wants a small fast-acting or midget fuse instead. For energy meter protection specifically, the Square D PowerLogic Energy Meter Fuse Pack is a purpose-built set of three at 0.5A, 600V, which also gets you the 600V rating a metering CT circuit on a 480V service needs and the TR-R cannot provide at its 250V rating.
10) I need a low-amp fuse for a control circuit - is a 0.5A meter fuse the same thing as a 1A TR1R?
They are not interchangeable. The TR1R is the 1A member of the Mersen TR-R Class RK5 time-delay family, clip mounted with copper ferrule terminals and rated 250VAC with a 200 kA breaking capacity, so it drops into the same RK5 fuse block that carries the larger amperages in the series. The Square D PowerLogic fuse pack is a set of three 0.5A 600V fuses supplied for a PowerLogic energy meter and sized for that meter's sensing leads, not for a control transformer secondary or a starter coil circuit. For a control circuit fed from a standard RK5 block, the TR1R or TR2R is the part that fits the holder you already have.
11) Which fuse do I use on the metering section of a switchboard versus the motor feeder in the same lineup?
They are two different parts in the same enclosure. The metering section takes the Square D PowerLogic energy meter fuse pack, a set of three 0.5A 600V fuses matched to the PowerLogic meter. The motor feeder takes a Mersen TR-R Class RK5 time-delay fuse at the amperage the motor calls for, clip mounted, rated 250VAC with a 200 kA breaking capacity and a time-delay curve that rides through starting inrush. Ordering one for the other stalls the job either way: the meter fuse cannot carry a motor, and a feeder-sized RK5 gives the meter no protection at all.
12) I have a DC circuit to protect - does the meter fuse pack or the TR-R cover it?
The Mersen TR-R series is rated for both AC and DC service, which is why it turns up on power supply, converter and process control circuits as well as on AC motor loads, and it holds a 200 kA breaking capacity with a time-delay characteristic on a clip-mounted RK5 block. The Square D PowerLogic fuse pack is a 0.5A 600V set supplied for a PowerLogic energy meter and is applied to that meter's sensing leads. For DC equipment protection, the TR-R at the required amperage is the part that matches the duty.
13) Is the Mersen TR-R fuse RoHS compliant for a government or institutional spec?
Yes, the TR-R Series is RoHS compliant, which is the one environmental compliance item carried on it. Facilities standardizing on the series can order any rating from 1A to 500A on the same compliance basis.
14) What is the fuse body made of and will it hold up in a hot control panel?
The TR-R uses a PolyTube insulating body with copper end terminals. That is a melamine-type insulating tube rather than glass, so it takes the mechanical handling of pulling and reseating in a starter and the thermal cycling of a motor control center without the fragility of a glass-tube fuse.
15) What is the difference between a fuse that ships as a matched set of three and ordering fuses one amperage at a time?
The Square D PowerLogic energy meter fuse pack is sold as a set of three 0.5A 600V fuses, which suits a three-phase metering installation where all three sensing legs get replaced together at one value. The Mersen TR-R series is ordered by amperage instead - 15A, 30A, 60A-class steps and on up through 110A, 150A, 200A, 250A, 300A, 400A and 500A - because the branch or feeder value is set by the load, and a shop stocking a facility usually carries several amperages rather than one repeated three times. For a three-phase motor you order three of the same TR-R amperage; for the meter leads the matched pack is the maintenance item.
How fast can I get the Mersen TR1R 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 TR1R come with a warranty?
Absolutely. The Mersen TR1R 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 TR1R?
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
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