Red Housing 175A Continuous Rating Marine Battery Isolator Switch DC 12V-36V Battery Disconnect Switch

The MT040-R is the red-finish version of the MT040 master switch. Mechanics and installers often want the kill switch to stand out on a dark dash or inside a black battery box, and a red cover does exactly that — the unit is spotted immediately when someone needs to cut power in a hurry. The electrical package underneath is unchanged from the standard model.

Operation is a straight two-position rotary: turn to ON to close the circuit, turn to OFF to break it. There is no third position and no combined-bank option, which keeps the switching logic obvious for charter crews, rental fleets and family boats where several people use the same vessel.

The contacts are built for 175 amps of continuous current and accept supply voltages from 12 up to 36 volts DC. That range covers a 12V outboard, a 24V commercial hull and a 36V electric-drive pack, so a single part number keeps spares simple across a mixed fleet.

• Fast visual identification — the red body separates the master isolate from fuse holders and busbars on a crowded panel.
• Clear emergency cue — crew can find the cut-off by colour before reading any label.
• Identical electrics — same 175A rating, same 12V–36V window, same copper current path as the MT040.
• Fleet colour coding — use red for the main isolate and another finish for auxiliary circuits.

• Rotary knob with hard stops at ON and OFF, so the switch cannot rest between contacts.
• Copper conductors inside the housing keep volt drop and stud heating low during long charge cycles.
• Moulded body with a flat fixing flange that sits square on dash panels and locker walls.
• Oversized terminal studs accept standard crimped ring lugs without stepping cable gauge down.
• Coloured housing is moulded, not painted, so the finish does not flake at the mounting screws.

Owners fit this switch wherever one battery bank feeds a mixed DC board and a single cut-off point is wanted. Common cases are the helm of a sports boat, the entry panel of a camper conversion, the winch feed on a 4x4, and the battery tray of a small commercial van. In each case the switch sits between the battery positive and the distribution fuse block, so pulling it dead-isolates everything downstream.

1. Disconnect the battery negative lead and prove the circuit is dead before touching any cable.
2. Lay out the switch on the panel, check the knob has full swing and the cables can bend without strain.
3. Mark and drill the flange holes, then fasten the body down with even pressure.
4. Connect battery positive to one stud, distribution feed to the other.
5. Crimp ring lugs on both cable ends and torque the nuts fully; loose joints are the main source of heat.
6. Sweep ON-OFF once with no load, then reconnect and confirm stud temperature stays cool under working current.

Leave the switch at OFF during storage, transport and any service work. Rinse salt deposits off the housing after coastal use, check nut torque at the start of each season, and replace cable with corroded lugs rather than simply retightening it.

• Minimum order — 5 pcs.
• Price — negotiable, quoted against quantity and packing requirements.
• Capacity — 50,000 pcs per month.
• Lead time — 30 days for standard production.
• Payment — T/T or Western Union; 30% deposit with the balance before shipment.
• Packing — neutral white box inside a brown carton; branded packing available with written trademark authorisation.