Mersen Class J Fuse Block, 600...
IN STOCK (leaves warehouse same day if ordered before 3pm ET)
$4,180.73
Mersen Class J Fuse Block, 600A 3-Pole, 600VAC/600VDC Phenolic

Mersen Class J Fuse Block, 600A 3-Pole, 600VAC/600VDC Phenolic

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Model: 6633J

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

$4,180.73
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Mersen Class J Fuse Block, 600A 3-Pole, 600VAC/600VDC Phenolic

The Mersen Class J Fuse Block is a heavy-duty 3-pole fuse block rated 600A at 600VAC/600VDC, engineered for 200-600A bladed Class J fuses. Built with a phenolic insulating body and high-conductivity tinplated copper fuse clips, this direct screw-mount block delivers verified dielectric strength in excess of 2500V and a 200kA short circuit current rating (SCCR), making it well suited for demanding industrial and commercial power distribution applications.

Key Features

  • Ampere Rating: 600A ampere rating with a 600A max fuse rating, sized for 200-600A bladed Class J fuses.
  • 3-Pole Configuration: 3-pole design supports three-phase circuit protection.
  • Dual AC/DC Rating: UL rated 600V AC and 600V DC (AC/DC) at 50/60 Hz for flexible power system use.
  • Durable Construction: Phenolic body/insulating material with verified dielectric strength in excess of 2500V.
  • High-Conductivity Fuse Clips: Tinplated copper clips designed specifically for 200-600A bladed Class J fuses, with a Clip-In installation method.
  • Direct Screw Mount: Direct screw mounting with a 500 lb-in torque rating for a secure, reliable installation.
  • High SCCR: 200kA short circuit current rating for demanding fault-current applications.

Certifications & Compliance

  • RoHS Compliant

Technical Specifications

  • Torque Rating: 500 lb-in
  • Ampere Rating: 600 A
  • ROHS Compliant: Yes
  • Frequency: 50/60 Hz
  • Rated Voltage AC (UL): 600 V
  • Number of Poles: 3-Pole
  • AC or DC: AC/DC
  • Fuse Type/Class: Class R
  • Short Circuit Current Rating (SCCR): 200 kA
  • Installation Mounting: Direct Screw Mount
  • Max Fuse Rating: 600 A
  • Fuse Installation Method: Clip-in
  • Rated Voltage DC (UL): 600 V
  • Fuse Class: Class J
  • Body/Insulating Material: Phenolic
  • Packaging: 1 EA

Typical Applications

  • Industrial Power Distribution Panels
  • Motor Control Centers
  • Three-Phase Circuit Protection
  • Class J Fuse Protection Systems
  • Commercial and Industrial Electrical Installations

Why Mersen?

Mersen fuse blocks combine a phenolic insulating body with high-conductivity tinplated copper fuse clips to deliver dependable, code-compliant Class J fuse protection. With a 600A rating, 600VAC/600VDC dual voltage rating, and a 200kA SCCR, this RoHS compliant fuse block is built for reliable performance in demanding professional electrical systems.

Manufacturer Resources

Mersen Product Catalog

Product Specs

list_batch:
MERSEN-20260825
Product Type:
Fuse Block
Product Material:
Phenolic
Amperage Rating:
600A
Voltage Rating:
600VAC/600VDC
Configuration:
3-Pole
Connection Type:
Clip-In
Standards:
RoHS Compliant
Department:
Electrical
Product Group:
Circuit Protection
Product Subgroup:
Fuse Holders & Blocks

Mersen 6633J – Frequently Asked Questions

1) Will the Mersen 6633J fuse block take 400A or 500A Class J fuses, or only 600A?
The 6633J accepts bladed Class J fuses from 200A through 600A, so 400A and 500A fuses drop straight into the same clips. The block itself is rated 600A, which is the maximum fuse size it will carry. Below 200A the blade dimensions change and you need a smaller Class J block.
2) Can I use this Mersen fuse block on a 600V DC circuit, not just AC?
Yes. The 6633J is UL rated 600V AC and 600V DC, at 50/60 Hz on the AC side, so it works in DC distribution and drive applications as well as three-phase AC panels. Dielectric strength is verified in excess of 2500V.
3) How does the Mersen 6633J mount in a panel, and do I need a DIN rail?
No rail needed. The 6633J is a direct screw mount block, fastened straight to the panel pan or subplate. Terminal torque rating is 500 lb-in. If your build is standardized on rail-mounted blocks, a DIN rail unit like the Littelfuse LFG60015-1SQDINR Class G block is a different mounting style, but that one is a 15A Class G device, not a 600A Class J.
4) What SCCR does the Mersen 6633J carry for a motor control center build?
200kA short circuit current rating, which is what lets it sit in an MCC or industrial distribution panel on a high available-fault-current service. The 3-pole configuration covers all three phases in one block.
5) Can I use a Bussmann CHPV2 photovoltaic fuse block in place of the Mersen 6633J on a DC circuit?
No. Although the Mersen 6633J is UL rated 600V DC as well as 600V AC, the Bussmann CHPV2 Series block is a modular two-pole photovoltaic block rated 1000 Vdc and intended for PV string fusing. The 6633J is a three-pole block for 200-600A bladed Class J fuses in three-phase industrial power distribution and motor control centers. They are not substitutes in either direction: the CHPV2 will not accept Class J blades, and the 6633J is not rated for a 1000 Vdc PV array.
6) What is the difference between the Mersen 6633J fuse block and the Littelfuse LFR60030-3CID?
Both are three-pole, 600V fuse blocks, but they take different fuses at very different amperages. The Mersen 6633J is built for 200-600A bladed Class J fuses and carries a 600A amperage rating at 600VAC/600VDC with a clip-in connection. The Littelfuse LFR60030-3CID is a Class R fuse block rated 600V 30A. If the drawing calls for Class J fuses on a 600A feeder, the 6633J is the match; a 30A Class R branch circuit needs the Littelfuse.
7) I need a 600V block for small control-circuit fuses, not 600A Class J. What should I use instead of the Mersen 6633J?
The Mersen 6633J is sized for 200-600A bladed Class J fuses, which is far more block than a control circuit needs. For low-amperage control fusing at 600V, 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. Pick by the fuse class your schedule specifies, since Class G, Class CC, and Class J fuses are not interchangeable in the same clips.
8) Is a Class J fuse block the right choice, or should I be using Class R?
Class J is the more compact, higher-interrupting choice and its clips are rejection-style, so only Class J fuses fit, which keeps someone from downgrading the protection later. The 6633J is built for 200-600A bladed Class J. If your existing equipment is specified for Class R, use a Class R block such as the Littelfuse LFR60030-3CID (600V, 30A) rather than forcing a swap, since the two classes are not interchangeable in the same clips.
9) Do the fuses bolt into this Mersen block or clip in?
Clip-in. The 6633J uses tinplated copper clips sized for bladed Class J fuses, so fuse changes are pull-and-push with no terminal hardware to remove. If your spec calls for bolted fuse mounting instead, the Littelfuse LD Series POWR-BLOKS block is a bolt-in design.
10) My panel layout needs a bolt-in fuse block rather than a direct screw mount block like the Mersen 6633J. What else is there?
The Mersen 6633J uses direct screw mounting with a 500 lb-in torque rating and clip-in fuse installation. If your enclosure is laid out for bolted mounting, the Littelfuse LD Series POWR-BLOKS fuse block is a bolt-in mounting block. Confirm the fuse class and ampere rating of the POWR-BLOKS version you order against your fuse schedule before you swap, because the 6633J clips are specific to 200-600A bladed Class J fuses.
11) Is a Bussmann 3833 Series AGC fuse block an alternative to the Mersen 6633J?
They serve completely different circuits. The Bussmann 3833 Series is an AGC fuse block offered in 1 to 8-pole configurations for small glass-tube AGC fuses. The Mersen 6633J is a 600A three-pole block with tinplated copper clips for 200-600A bladed Class J fuses, a 200kA SCCR, and a phenolic body. Use the 3833 for low-current instrument and auxiliary fusing, and the 6633J where the feeder is protected by Class J fuses.
12) I only need two poles, not three. What are my options compared with the Mersen 6633J?
The Mersen 6633J is a three-pole block, built for three-phase circuit protection. For two-pole applications, 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 finger-safe design and blown-fuse indicator. Match the fuse class first - the 6633J accepts only 200-600A bladed Class J fuses, so a two-pole block is a change of fuse type as well as pole count.
13) Which fuse block should I standardize on for a DIN rail control panel instead of the Mersen 6633J?
The Mersen 6633J mounts by direct screw to a panel surface, so it is not a DIN rail part. For DIN rail mounting, the Littelfuse LFG60015-1SQDINR is a Class G fuse block rated 600V 15A with DIN rail mount, and both the Bussmann BCM603 Series and the Bussmann CHCC2DIU are modular blocks. Reserve the 6633J for the 600A Class J feeder positions in the same facility.
14) Is the body on this 600A fuse block thermoset or plastic?
Phenolic, a thermoset insulating material, with tinplated copper fuse clips. That combination is why the block is rated for continuous 600A service and verified above 2500V dielectric. Phenolic holds up better to clip heat at high amperage than a thermoplastic housing.
15) Is the Mersen 6633J RoHS compliant for a government or institutional spec?
Yes, the 6633J is RoHS compliant. Ordering identity is straightforward: Mersen part number 6633J, supplied one each.
How fast can I get the Mersen 6633J delivered?
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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 6633J come with a warranty?
Absolutely. The Mersen 6633J 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 6633J?
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