Mersen 6633R Class R 3-Pole Bo...
IN STOCK (leaves warehouse same day if ordered before 3pm ET)
$1,899.00
Mersen 6633R Class R 3-Pole Box Connector Fuse Block, 600V

Mersen 6633R Class R 3-Pole Box Connector Fuse Block, 600V

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Model: 64033J

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

$1,899.00
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Mersen 6633R Class R 3-Pole Box Connector Fuse Block, 600V

The Mersen 6633R Class R 3-Pole Box Connector Fuse Block is engineered to accommodate Class R power fuses in demanding industrial and commercial power distribution systems. This fuse block is available with a Motor FLA rating of 400A or 600A, giving specifiers the flexibility to match the block to the connected motor load while retaining the same rugged construction across the family. Every version of this 3-pole fuse block features clip-in fuse installation with a box connector design, is rated 600V AC/DC per UL, and carries a Short Circuit Current Rating (SCCR) of 200 kA for high fault-current environments. Built on a phenolic insulating body with dielectric strength in excess of 2500V, this fuse block delivers dependable, code-compliant fuse protection for panelboards, switchgear, and OEM equipment, regardless of the Motor FLA option selected.

Key Features

  • Motor FLA Range: Offered in 400A and 600A options to match a range of connected motor and circuit loads.
  • Configuration: 3-Pole design for multi-circuit fuse protection in a single mounting footprint.
  • Fuse Installation Method: Clip-in fuse retention with high-conductivity tinplated copper clips for reliable electrical contact.
  • Rated Voltage: 600V AC and 600V DC (UL) for use across a wide range of power distribution applications.
  • Short Circuit Current Rating (SCCR): 200 kA, supporting installations with elevated fault-current requirements.
  • Body/Insulating Material: Phenolic construction with verified dielectric strength in excess of 2500V for durable electrical isolation.
  • Installation Mounting: Direct screw mount for secure, straightforward panel installation.
  • Frequency: Rated for 50/60 Hz AC/DC operation.
  • Connector Type: Box connector accommodates stranded or solid copper or aluminum wire terminations.

Certifications & Compliance

  • UL Rated 600V AC/DC
  • RoHS Compliant

Technical Specifications

  • Motor FLA Options: 400A, 600A
  • ROHS Compliant: Yes
  • Rated Voltage AC (UL): 600 V
  • Rated Voltage DC (UL): 600 V
  • Number of Poles: 3-Pole
  • Short Circuit Current Rating (SCCR): 200 kA
  • Installation Mounting: Direct Screw Mount
  • Frequency: 50/60 Hz
  • AC or DC: AC/DC
  • Fuse Installation Method: Clip-in
  • Body/Insulating Material: Phenolic

Typical Applications

  • Industrial Power Distribution Panels
  • Motor Control Centers
  • Switchgear and Switchboard Assemblies
  • Commercial Electrical Distribution Equipment
  • OEM Panel Fabrication

Why Mersen?

Mersen fuse blocks pair a phenolic insulating body with dielectric strength exceeding 2500V and high-conductivity tinplated copper clips to deliver dependable performance under demanding electrical loads, whether specified in the 400A or 600A Motor FLA configuration. With a 600V AC/DC UL rating, 200 kA SCCR, and RoHS-compliant construction, this Class R fuse block is built for code-compliant, long-service fuse protection in professional electrical installations.

[{"name": "Product Type", "value": "Fuse Block"}, {"name": "Product Material", "value": "Phenolic"}, {"name": "Voltage Rating", "value": "600V"}, {"name": "Amperage Rating", "value": "400A-600A"}, {"name": "Configuration", "value": "3-Pole"}, {"name": "Connection Type", "value": "Clip-in"}, {"name": "Listing", "value": "UL Listed"}]

Manufacturer Resources

Mersen Product Catalog

Product Specs

Rated voltage AC UL:
600 V
Number Of Poles:
3-Pole
Short Circuit Current Rating Sccr:
200 kA
Installation Mounting:
Direct Screw Mount
ROHS Compliant:
Yes
Frequency (Hz):
50/60 Hz
AC or DC:
AC/DC
Fuse Installation Method:
Clip-in
Rated voltage DC UL:
600 V
Body/Insulating Material:
Phenolic
list_batch:
MERSEN-20260825
Product Type:
Fuse Block
Department:
Electrical
Product Group:
Circuit Protection
Product Subgroup:
Fuse Holders & Blocks

Mersen 64033J – Frequently Asked Questions

1) Can this fuse block be used on a 600V DC circuit, not just AC?
Yes. It's rated 600 V AC and 600 V DC per UL, and listed for AC/DC service at 50/60 Hz. That covers both standard three-phase distribution and DC applications up to 600 V.
2) Does this Mersen Class R block meet a 200 kA SCCR requirement on my panel drawing?
It carries a 200 kA Short Circuit Current Rating, which is the number panel builders need when documenting assembly SCCR on high fault-current services. The block is also UL rated at 600V AC/DC and RoHS compliant.
3) I only need a 30A Class R block for a small disconnect. Is the Mersen 6633R overkill?
Yes, for a 30A branch it is. The 6633R family starts at a 400A Motor FLA rating. For a small circuit, the Littelfuse LFR60030-3CID is a Class R block rated 600V 30A. Keep the 6633R for 400A and 600A feeders and large motor loads.
4) What is the closest Class R alternative to the Mersen 6633R fuse block?
The Littelfuse LFR60030-3CID is also a Class R fuse block rated 600V, and it is a three-pole block like the Mersen. The key difference is the current range: the Littelfuse LFR60030-3CID is a 30A block, while the Mersen 6633R family covers 400A and 600A Motor FLA ratings with box connectors and clip-in fuse retention. Use the Littelfuse where the branch circuit is small; stay with the Mersen for feeder and motor-circuit amperages.
5) I need a 600V fuse block for a small control circuit, not a 400A motor feeder. What should I use instead of the Mersen 6633R?
The Mersen 6633R family is built for 400A and 600A Motor FLA loads, which is far more block than a control circuit needs. For a low-amperage 600V control circuit, the Littelfuse LFG60015-1SQDINR is a Class G fuse block rated 600V 15A with DIN rail mounting, and the Bussmann CHCC2DIU is a two-pole Class CC modular block that is finger-safe with a blown-fuse indicator. Note the fuse class changes with the block, so the fuse you order has to change too.
6) What wire can I land on the box connectors of this Mersen fuse block?
The box connector terminals accept stranded or solid copper or aluminum conductors, so you can land Al feeder cable directly without a separate adapter lug. Fuse contact is through tinplated copper clips.
7) Is this a finger-safe fuse block for an enclosure that gets serviced live?
No. The 6633R is an open clip-in block with box connector terminals, not a finger-safe design. Where touch-safe construction is required, the Bussmann CHCC2DIU is a finger-safe Class CC modular block with blown-fuse indicator, though it is 2-pole Class CC rather than 3-pole Class R.
8) I need a bolt-in fuse block instead of clip-in for a high-vibration panel. What are my options?
The Mersen 6633R retains the fuse by clips, so the fuse itself is not bolted. If the specification calls for bolt-in mounting, the Littelfuse LD Series POWR-BLOKS fuse block is a bolt-in design. Note that switching families also changes the fuse class you must stock.
9) Is the Bussmann 3833 AGC fuse block a substitute for the Mersen 6633R?
No. The Bussmann 3833 Series takes AGC glass-tube fuses and is offered in 1 to 8-pole configurations for low-current electronic and auxiliary circuits. The Mersen 6633R is a Class R power fuse block with box connectors for stranded or solid copper or aluminum conductors, rated 600V AC/DC with a 200 kA SCCR. They serve opposite ends of the circuit-protection range.
10) My panel drawing calls for a bolt-in power fuse block rather than a screw-mount one. What is the alternative to the Mersen 6633R?
The Mersen 6633R is a direct screw mount block. If the assembly spec calls for bolt-in mounting, the Littelfuse LD Series POWR-BLOKS fuse block uses bolt-in mounting instead. Confirm the fuse class and amperage of the LD block you select matches the Class R fuse you intend to install before you swap.
11) Is a phenolic fuse block body good enough for a hot motor control center?
The body is phenolic, a thermoset insulator, with dielectric strength verified in excess of 2500V. That is the standard construction for 600V Class R blocks in motor control centers, switchgear, and OEM panels, and it holds its shape under the heat a 400A to 600A fuse puts out better than a thermoplastic housing.
12) I am standardizing a motor control center on DIN rail. Does the Mersen 6633R fit that approach?
The Mersen 6633R mounts by direct screw to the panel rather than clipping to DIN rail. For the DIN rail portions of the assembly, the Littelfuse LFG60015-1SQDINR is a 600V 15A Class G block with DIN rail mount, which suits control and auxiliary circuits; the Mersen remains the block for the 400A and 600A Motor FLA power section.
13) Which block should I pick if I only need two poles at 600V?
The Mersen 6633R is a three-pole block, so it is more than a two-pole circuit requires. Among two-pole options, the Bussmann BCM603 Series is a two-pole modular fuse block and the Bussmann CHCC2DIU is a two-pole Class CC modular block with a blown-fuse indicator. Match the fuse class and amperage of the two-pole block to your circuit, since neither takes the Class R power fuses the Mersen accepts.
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Does the Mersen 64033J come with a warranty?
Absolutely. The Mersen 64033J 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 64033J?
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