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Mersen R212 Class R Fuse Reducer, 200A to 100A, 600V AC/DC
The Mersen R212 Class R Fuse Reducer delivers reliable power distribution and circuit protection for professional electrical systems, reducing 200A circuits to 100A for flexible load matching. This UL Listed and CSA Certified reducer supports 600V AC/DC applications with a 200 kA SCCR rating, and its Class R rejection design prevents installation of non-current-limiting fuses to keep the system protected. Built for commercial and industrial power distribution panels, it ensures proper fuse coordination wherever high fault-current protection is required.
Key Features
- 200A to 100A Reduction: Enables flexible circuit design and proper load matching in power distribution systems.
- 600V AC/DC Rating: Supports both alternating and direct current applications up to 600 volts for versatile installation options.
- Class R Design: Provides a rejection feature that prevents installation of non-current-limiting fuses, ensuring system safety.
- 200 kA SCCR: High short-circuit current rating delivers robust fault protection in high-capacity electrical systems.
- UL Listed & CSA Certified: Meets rigorous safety standards with E105670 IZZR and 6225-01 207417 certifications for code compliance.
- Multi-Standard Compliance: Supports 250V and 600V Class H, K, and R applications plus 600V Class J systems.
Certifications & Compliance
- UL Listed, Guide No. IZZR, Certification E105670
- CSA Certified, 6225-01 207417
- 600V Class J - UL Listed
- 250V and 600V Class H, K, and R - UL Listed Guide No. IZZR, CSA Certified
Technical Specifications
- AC Voltage: 600 VAC
- DC Voltage: 600 VDC
- Class: R
- SCCR: 200 kA
- CSA Certification: 6225-01 207417
- UL Certification: E105670 IZZR.E105670
- Standards: 250V and 600V Class H, K, and R - UL Listed Guide No. IZZR, CSA Certified. 600V Class J - UL Listed
Typical Applications
- Commercial Power Distribution Panels
- Industrial Control Centers
- Manufacturing Facility Electrical Systems
- Data Center Power Infrastructure
- Healthcare Facility Electrical Distribution
- Municipal and Government Buildings
Why Mersen?
Mersen delivers proven reliability in electrical protection with comprehensive UL and CSA certifications ensuring code compliance and system safety. The 200 kA SCCR rating and multi-standard compliance across 250V and 600V Class H, K, R, and J systems provide confidence for professional power distribution work where circuit protection integrity is critical.
Manufacturer Resources
Mersen Product Catalog
Product Specs
- Ac Voltage:
- 600 VAC
- Ce Conformity:
- Consult Technical Services
- Class:
- R
- Csa Certification:
- 6225-01 207417
- Dc Voltage:
- 600 VDC
- Lead Free:
- Consult Technical Services
- Rohs Compliant:
- Consult Technical Services
- Sccr:
- 200 kA
- Ul Certification:
- E105670 IZZR.E105670
- Department:
- Electrical
- Product Group:
- Circuit Protection
- Product Type:
- Fuse Reducer
- Product Subgroup:
- Fuse Holders & Blocks
Mersen R212 – Frequently Asked Questions
1) What does a Mersen R212 fuse reducer actually do in a panel?
The R212 lets you install 100A Class R fuses in a switch or panel whose fuse clips are built for 200A fuses. You mount the reducers in the existing 200A clips and they accept the smaller 100A fuse body, so you can match protection to the actual load without changing out the disconnect. Rated 600 VAC and 600 VDC.
2) Will the R212 reducer hold up on a high fault-current service?
It carries a 200 kA short circuit current rating, which is the same interrupting level Class R current-limiting fuses are built around. That covers commercial and industrial services where available fault current at the panel is high.
3) Does a Class R reducer stop someone from dropping in a cheap non-current-limiting fuse?
That is the point of the Class R rejection feature. The R212 only accepts Class R rejection-style fuses, so a standard Class H or K fuse of the same amperage will not seat. If your system coordination depends on current-limiting protection, that rejection keeps a later maintenance swap from defeating it.
4) Is the Mersen R212 fuse reducer UL Listed and CSA certified for an inspected job?
Yes. UL Listed under Guide No. IZZR, certification E105670, and CSA Certified under 6225-01 207417. That covers 250V and 600V Class H, K and R applications, plus 600V Class J as UL Listed.
5) What is the alternative to the Mersen R212 fuse reducer from another manufacturer?
The Littelfuse LRUR Series (also catalogued as the LRU2 Series) is a fuse clip adapter style reducer that serves the same purpose of adapting a fuse clip to a smaller fuse size. The Mersen R212 is a Class R reducer rated 600 VAC and 600 VDC with a 200 kA SCCR, taking a 200A clip down to a 100A fuse. When cross-shopping, confirm the Littelfuse part you pick matches the amp step and voltage class of the switch you are working in, since the LRUR family spans a range of sizes rather than a single step.
6) Can I use a Mersen R212 reducer on a DC circuit?
Yes. The R212 carries both a 600 VAC and a 600 VDC rating, so it works in DC distribution as well as AC gear up to 600 volts.
7) How many fuse reducers do I need for a three-phase disconnect?
Reducers work in pairs per fuse, one at each end of the fuse, so a three-pole 200A switch being stepped to 100A takes six R212 reducers. Order by the pole count of the switch, not by the number of fuses.
8) Is there an alternative to the Mersen R212 if I need a different reduction size?
Littelfuse builds the LRUR Series (also shown as LRU2 Series) fuse clip adapters for the same job. They are the direct cross-brand equivalent when you need a fuse reducer in another amperage step. Confirm the ampere in and ampere out on the specific LRUR part matches your switch clips and the fuse you intend to install.
9) When should I not use a fuse reducer like the Mersen R212 and change the fusible switch instead?
A reducer such as the R212 adapts an existing 200A fuse clip to accept a 100A Class R fuse in the same disconnect, so it fits when the switch itself is staying. If the opening calls for a different voltage class than the 600 VAC / 600 VDC the R212 covers, or the assembly needs a rejection style other than Class R, a reducer will not get you there and the switch or fuse block has to be changed. The Littelfuse LRUR Series is the comparable fuse clip adapter approach if you want a second source for the same reducer strategy.
10) Is a fuse block or fuse holder a substitute for the Mersen R212 reducer?
No. The R212 is a fuse reducer, a pair of adapters that fit into existing 200A clips so a 100A Class R fuse can be installed in the same switch. A fuse block or holder is the mounting base itself and replaces the clip assembly rather than adapting it. If you want a like for like reducer from another maker, the Littelfuse LRUR Series fuse clip adapter is the equivalent type of part.
11) Is the Mersen R212 RoHS compliant or lead free?
Mersen lists RoHS status, lead free status and CE conformity for the R212 as items to confirm with their technical services rather than publishing a fixed value. If your spec requires a documented RoHS or lead-free declaration, get that confirmation in writing before submittal.
12) What is the Mersen part number for a 200A to 100A Class R fuse reducer?
R212 is the Mersen part number for the 200A to 100A Class R reducer, rated 600V AC/DC.
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Does the Mersen R212 come with a warranty?
Absolutely. The Mersen R212 is backed by a manufacturer’s warranty.
For full warranty terms, check the product documentation or Contact Us.
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