Mersen D70QS400-4 D70QS Series High-Speed DC Fuse, 700VDC, 400A aR, 4.34in Round Body - Pack of 5

Overview: The Mersen D70QS400-4 is a North American style round-body high-speed semiconductor fuse from the D70QS Series. Rated 400 A at 700 VDC with L/R ≤1 ms and a 20 kA DC interrupting rating, it provides rapid short-circuit protection for DC power electronics and battery-related systems. This item is sold as a pack of 5 units.

Key Features:

• 700 VDC rating (L/R ≤1 ms) with 20 kA interrupting rating
• aR characteristic for semiconductor short-circuit protection
• Low I²t and low watts losses for improved device protection
• Superior cycling ability; vibration-resistant construction
• UL Recognized (UL File E60314); REACH/RoHS compliant

Technical Specifications:

• Electrical ratings: 400 A, 700 VDC, L/R ≤1 ms, 20 kA IR
• Power dissipation: 11.7 W at 0.5×In
• Minimum Breaking Capacity (MBC): 2100 A; maximum time to clear MBC: 140 ms
• Dimensions (D70QS 225–400 frame): A=4.34 in (110 mm), B=1.50 in (38.1 mm), C=2.09 in (53.1 mm), D=3.41 in (86.6 mm), E=2.78 in (70.6 mm), F=0.41 in (10.4 mm), G=1.00 in (25.4 mm), H=0.25 in (6.4 mm)
• Weight: 0.26 kg per fuse
• Mounting/accessories: compatible with P243C fuse blocks (D70QS 225–600 A) and 1SC/1MSC modular fuse blocks (see catalog)

Applications:

• Energy Storage Systems (ESS) and Battery Disconnect Units (BDU)
• Battery charging and management systems
• DC fast‑charging stations and DC grids
• Backup protection for DC relays/disconnectors/switches
• UPS and inverter protection up to 700 VDC