VTi by M. Davis Fused Distribution Panel (FDP)

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VTi by M. Davis Fused Distribution Panel (FDP) is designed to provide electrical power distribution in applications requiring high-speed clearing of branch-circuit load faults from the supply source. The FDP is available for single-phase and three-phase input voltages and can accommodate single, double, or three pole switches, up to 42 pole positions per unit (or more by special order). Each branch switch output feeds a high-speed, sub-cycle clearing fuse which in turn feeds the load.

The FDP is supplied with UL and/or CUL labels. They are engineered, assembled and tested at our factory to your specifications, and then are shipped to the customer’s site ready for installation. The net result is a completely self-contained, easy to order, and easy to install fused power distribution panel meeting OSHA and NEC electrical standards.


Typical applications include power distribution from an uninterruptable power supply, where standard thermomagnetic breakers are too slow to coordinate with the automatic transfer bypass circuit in a UPS. During a branch circuit fault, the UPS transfers back to the utility source to clear the fault. After the fault is cleared, the UPS transfers back to the UPS output. This transfer takes place because the UPS has limited short circuit capacity and cannot produce enough short circuit current to cause an ordinary branch breaker to reach its instantaneous trip level. On occasion you can drop the load during the transfer cycle or worse case, have the UPS transfer to the utility voltage source that is not there. The solution is to incorporate the FDP into your system network. Select the proper high-speed fuse with appropriate clearing time curve and current rating (from 0.1A to 30A).

The FDP is also useful for power distribution to multiple small electrical loads such as electronic instruments, where fuses can be sized down to 0.1 amps for precise load protection for sensitive instruments. This offers an advantage over a standard panelboard where the smallest breaker is 10 amps.


FDPs can use either a molded case circuit breaker (MB Series) or a fused disconnect switch (FD Series) as the main secondary protection device. The FDP is also available with a Main Lug Only disconnect option (MLO Series).

Optional neon indicator lights on each output will indicate blown fuses.

All of our fused power distribution panels can be configured from the following options:

Main Disconnect:

  • Molded-case circuit breaker (MB)
  • Fused disconnect switch (FD) – high-speed current-limiting fuses in series with the Main Breaker
  • Main Lug Only (MLO)

Power Input:

  • 240/120V single phase
  • 120V 2-wire single phase
  • 208/120V three phase 4-wire

Branch Switches:

  • Single pole for 120V circuits
  • Double pole for 208 or 240V circuits
  • Three pole for 3-phase 208V circuits


  • NEMA 1 (standard)
  • NEMA 3, 4, 4X and 12 also available

Optional Features:

  • Neon Blown Fuse Indicator Lights (BFI)
  • All-copper bus, lugs and neutral (ACU)
  • Bolt-on circuit breakers (BON)
  • Isolated Ground Bus – Aluminum (IGB) or Copper (IGBCU)
  • Number of Poles and Main Disconnect Current Rating

Download Spec Sheet

FDP unit enclosed
FDP panel, open


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M Davis Inc.