Magnum Energy ME-300F User Manual

ME-300F and ME-400F Instruction Sheet

© 2011 Magnum Energy, Inc.

Magnum Energy, Inc.

2211 West Casino Rd.

Everett, WA USA 98204

425-353-8833

www.magnumenergy.com

Introduction

The Magnum Energy Class-T Fuse/Fuse Block is designed to provide code
compliant overcurrent protection. It protects the battery bank, inverter,
and cables from damage caused by short circuits and overloads. A fast
acting, current-limiting Class-T fuse cartridge delivers instantaneous
protection in the event of a short circuit, as well as a time delay to allow
the momentary current surges that are common in inverter applications.
Magnum large fuse blocks are available in 300 and 400 amp models.
A rugged injection-molded polycarbonate base and thermoformed ABS
cover provide durability, easy installation, and good looks in a compact,
cost effective package.

Fuse selection is based upon the size of the conductor between the
battery and the load. Keep in mind that the conductor’s current carrying
capability is affected by: the length of the cable between the battery
and the load, and the conductor’s wire type and temperature rating.
Refer to Table 1 for assistance in selecting a fuse.

Installation

The battery, fuse block, and inverter should be located as close together
as possible – without being in the same enclosure. Batteries can produce
explosive gasses that may be ignited by the fuse. For code compliance, lo­cate the fuse within 18” (45 cm) of the battery, and with at least 6” (15 cm)
clearance from other equipment on each end. When changing the fuse, it
may be energized by the battery; allow additional clearance if grounded
metal surfaces (such as the inverter’s chassis) are nearby.

Attach the fuse block base to a secure surface using the appropriate
hardware (refer to Figure 1). Make the connections to the fuse block
fi rst (see Figure 2 for proper hardware stacking), then to the battery,
and fi nally to the inverter.

NOTE: Do not install the fuse in the grounded conductor.

Torque the Hex nuts to ~244 inch-pounds (27.6 N-m). The lock washers
provided must be installed to ensure a quality and long lasting connection.

Check the cables for correct polarity with a voltmeter before making the
fi nal connections to the inverter. Replace the fuse block’s cover to prevent
accidental contact with the fuse’s live terminals.

WARNING: Failure to comply with torque specifi cations
may result in damage and premature failure of the product.
Failures caused by not adhering to the proper torque speci­fi cations are not covered by warranty.

WARNING: Before replacing a fuse, ensure all AC/DC power
sources are de-energized (i.e., breakers opened, fuses re­moved) to prevent accidental shock.

ME-300F and ME-400F Instruction Sheet

© 2011 Magnum Energy, Inc.

Conductor Gauge Current Capacity* Recommended Fuse

#4/0 AWG/107.16 mm² 360 400**

#2/0 AWG/67.4 mm² 265 300**

* - Current capacity based on 75° C cable rating in free air @ 30° C (86° F).
** - The next larger standard size overcurrent device may be used if the

de-rated cable ampacity falls between the standard overcurrent devices
found in the NEC.

FUSE

CLASS-T

300 AMP

7.00" (17.78 cm)

6.25" (15.87 cm)

1.32"

(3.35 cm)

2.00"

(5.08 cm)

#10 (x4)

3/8 – 16 bolt w/ Hex nut (x4)

Requires 9/16" wrench

Figure 1, Large Fuse Block Dimensions

WARNING: During installation, incorrect stacking of the
fuse block hardware can create a highly resistive connec­tion that generates heat. DO NOT place anything (i.e.,

washers) between the fuse and either battery cable
lug as this can cause the fuse to overheat and blow open,

resulting in a partial melting of the fuse holder and cover.
Before stacking, refer to Figure 2.

Figure 2, Large Fuse Block Hardware Stacking

Mounting

Blocks

Battery

Cable Lugs

Hex Nuts

Fuse

Lock Washers

Table 1, Fuse Selection