400 Amp 300 Volt Fast Acting Class T Fuse · Littelfuse JLLN400
Littelfuse JLLN400 is a 400A Class T fast-acting fuse rated 300VAC and 125VDC with knife-blade construction for bolt-in mounting. It is commonly used where high interrupting capacity and fast fault clearing are required in industrial and commercial distribution equipment.
What this product is for
This is a Class T fast-acting fuse for overcurrent protection in industrial and commercial electrical systems. It is used to protect feeders, distribution equipment, and other circuits that need current-limiting protection with rapid fault clearing.
Use for
Use for 300VAC or 125VDC fused circuits requiring a 400A Class T fuse with knife-blade style construction. Common applications include switchboards, control panels, disconnects, and other equipment designed for Class T fuse protection.
Avoid for
Avoid using this fuse where a different fuse class, time-delay characteristic, voltage rating, or mounting format is required. Do not substitute it into holders or equipment not listed for Class T knife-blade fuses.
Best for
Best for electricians and maintenance teams replacing an existing 400A Class T fast-acting fuse in equipment that requires high interrupting rating and compact current-limiting protection.
Installed in
Typically installed in commercial and industrial distribution assemblies, OEM equipment, and fused power circuits using Class T fuse blocks or bolt-in fuse provisions.
Why this product exists
This fuse is designed to open quickly under fault conditions to help limit damage to downstream equipment and reduce let-through current. Fast-acting Class T fuses are commonly selected where equipment protection is a priority and available fault current may be high.
Compared with similar products
Compared with time-delay fuses, this fast-acting model clears faults more quickly and is generally chosen for circuits without high temporary inrush requirements. Compared with larger fuse classes, Class T fuses are commonly used where compact size and strong current-limiting performance are needed.
Specifications
- Manufacturer: Littelfuse
- Part number: JLLN400
- Series: JLLN
- Fuse class: Class T
- Current rating: 400A
- Voltage rating: 300VAC, 125VDC
- Response: Fast-acting
- Construction: Knife-blade / bolt-in
- Current-limiting: Yes
- Interrupting rating: 200 kA AC; 20 kA at 125VDC
- Indication: No
- Voltage300VAC, 125VDC
- SeriesJLLN
- Current Rating400A
- ConstructionKnife-blade / bolt-in
- Fuse ClassClass T
- Interrupting Rating200 kA AC; 20 kA at 125VDC
- IndicationNo
- BrandsLittelfuse
- Stock in Flesherton2
Aptico Supply Delivery
Fast Electrical Supply Delivery Across Ontario
Local delivery routes, pickup options, and contractor-focused service from our Elmira and Flesherton locations.
Delivery Built Around Electrical Contractors
Aptico Supply helps electricians, contractors, and commercial buyers get the electrical materials they need without unnecessary delays. Whether you are ordering for a jobsite, restocking service inventory, or arranging pickup, our delivery options are designed to keep work moving.
Free Daily Delivery
Free daily delivery is available for larger contractor accounts.
- Order by 9:00 AM for morning delivery
- Order by 2:00 PM for afternoon delivery
- Available in qualifying local delivery areas
Free Weekly Delivery
Free weekly delivery is available for smaller accounts in select service areas.
- Elmira area delivery: Tuesday
- Flesherton area delivery: Thursday
- Order by 11:00 AM on the route day
Pickup Options
Pickup is available from our Ontario locations for customers who prefer to collect their order directly.
- Elmira pickup available
- Flesherton pickup available
- Call ahead for large or special-order items
Local Delivery Areas
See our local delivery coverage below. Delivery charges may apply outside regular route areas or for oversized items.
Delivery Questions
Do you offer free delivery?
Yes, free delivery is available for qualifying contractor accounts and selected local delivery routes.
Can I pick up my order?
Yes, pickup is available from our Elmira and Flesherton locations.
Do delivery charges apply?
Delivery charges may apply outside regular local routes, for smaller orders, or for oversized and heavy items.
Can you deliver to jobsites?
Yes, jobsite delivery may be available depending on the order size, location, and delivery schedule.
Need Electrical Supplies Delivered?
Contact Aptico Supply to confirm your delivery options, pickup availability, or contractor account eligibility.
Contact Aptico SupplyWe accept the following payment methods:
To replace this text with your store's actual info on payment methods, go to "Design -> Menus & Pages -> Product Page Tabs" and edit the Payment methods page.
This page is intended for your policy regarding returns and refunds.
Here you can provide information as to what products can be returned, how many days your customers have to return their purchase, whether they will receive a refund in the original form of payment, a replacement or a store credit, who pays for the shipping of the previously purchased products to the store, and so on.
To replace this text with your store's actual return policy, go to "Design -> Menus & Pages -> Product Page Tabs" and edit the Return Policy page.