VTI DC Fused Distribution Panels (FDP-DC)

Wall-mounted High-speed Fused DC Power Distribution Unit

DC Fused Distribution Panels are available for 24VDC, 48VDC and 125VDC applications. 250 VDC and 500VDC are also available on special order. The FDP-DCs are available in Main Lug Only (MLO), Main Breaker (MB) and Main Fuses in series with the Main Breaker (FD) configurations.

FDP-DCs for 24VDC and 48VDC are packaged in the same enclosures and interiors as the standard FDP for single phase AC applications.

The FDP-DC utilizes single pole fuse holders in series with single pole circuit breakers, as the fuse holders are not rated as load break devices.

FDP Series Information

For more information on the FDP Series can be found here: Find out more...


Historically, 125VDC Distribution systems have always been floating systems consisting of a battery, charger, and distribution panel containing two pole breakers: one for the Positive (+) and the second for the Negative (–) Polarity. The main reason for this system configuration is system reliability. In a floating distribution system, if one polarity becomes grounded, the total system will remain operational. The chances of both the Positive and Negative Polarities becoming grounded at the same time is extremely low. In addition, most DC systems contain a simple “GROUND DETECTOR” consisting of two nominally rated DC pilot lights connected in series between the Positive and Negative polarities with the center of the pilot lights connected to “Ground”. Normally both lamps will glow at a low intensity since they are connected in series between the full system voltage. Therefore, if a “Ground” occurs on one polarity, one lamp will light at full intensity while the other lamp will not be lit. The source of the Ground may be determined and corrected before any system damage can occur.

The 125 VDC Fused Distribution Panels have all 2 pole branch circuits with a 2 pole DC rated branch circuit breaker (used as a switch to open the circuit under load) and with 2 - 150 VDC fuses, one each in the positive and negative legs of the DC circuit.

The 125VDC FDPs are available with main bus ratings of 125 amps, 250 amps and 400 amps. Since all of the 125 VDC circuits are 2 pole circuits in the standard configurations, the number of branch circuits are 8 (a 18-single pole circuit panel),14 (a 30-single pole circuit panel), and 20 (a 42-single pole circuit panel).

On special order 125VDC FDPs can be provided with a higher number of branch circuits. For example; the maximum number of branch circuits, for the 400 amp Main Breaker panel is 32 - 2 pole circuits and for the 250 amp Main Breaker panel is 44 – 2 pole circuits

Fuses for the 125VDC FDP:
Ferraz Shawmut Type A15QS(X) (where 'X' = Current Rating)
  • Fuse Current Ratings From 1 to 30 amps @ 150 Volts DC with a 100 KAIC rating @ 150 VDC
  • Physical Size: 13/32” dia X 1.5” long NEC Midget size
  • Tested to UL STD 198L and UL recognized
Fuse holders:
  • 2 pole Ultra-Safe touch free
  • Rated @ 30 amps @ 125VDC NON-LOAD Break
  • The modular fuse holder can be supplied with blown fuse indicators as an option



The following materials are available:

Ordering Information:

VTI can custom build a FDP-DC to your requirements for type and number of fuses, circuit breaker ratings, and input power.

You are welcome to contact VTI directly via email or phone with questions or to discuss specific requirements or to order FDP-DC units.

DC FDP Catalog Numbering System

VTI uses a systematic method to construct descriptive Model Numbers for the FDP Series, including the DC FDP. These model numbers include complete specifications on any unit and are suitable for inclusion in your Request for Quote, Project Plan or other documents. To build a model number for a FDP, please use the following guide:

FDP-DC-[disconnect][Rating]-[DC Voltage]-[#circuits]/[optionlist]

where the components of the model number include:
disconnect FD (Fused Primary Disconnect)
MB (Main Breaker)
MLO (Main Lug Only)
Rating (A) For MLO specify Bus Rating: 125 or 250, or 400
For MB and FD specify desired Ampere Rating, i.e. 108
DC Voltage (V) 24, 48, or 125
# circuits 20, 14 or 8 Circuit
optionlist CBL (VTI Circuit Breaker Lockout Kit)
BFI (Blown Fuse Indicator lights)
GD (Ground Detection Lights)
a 125V DC FDP with a 60A Main Breaker and 14 Branch Circuits, and including the Circuit Breaker Lockout kit and Ground Detection Indicator Lights, would have the model number:


typical dimensions
Dimensional Diagram of typical configuration. For more detail, download a PDF format drawing.
125VDC Enclosure Dimensions
No. of Circuits Height Width Depth Weight
8 (MLO) 32" 30" 5.6" 110
8 (MB) 42" 30" 5.6" 130
8 (FD) 42" 30" 5.6" 135
14 (MLO) 42" 30" 5.6" 130
14 (MB) 42" 30" 5.6" 140
14 (FD) 42" 30" 5.6" 145
20 (MLO) 42" 30" 5.6" 140
20 (MB) 47" 30" 5.6" 160
20 (FD) 47" 30" 5.6" 165
VTI · P.O. Box 9086 · 24 McMillan Way · Newark, DE 19714 · USA
Phone: (302) 738 0500 · Fax: (302) 738 6594

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