Key Lock Marine Battery Isolator Switch 250A Continuous Rating 2-ALL-1-OFF Battery Disconnect Switch

The MT048-K takes the four-stage copper isolator and adds a lock cylinder: the dial can no longer be turned by anyone who does not hold the key. That single change turns a convenient dual-battery switch into a controlled access point — useful wherever an unattended boat, stored camper or shared machine must stay electrically dead.

The electrical platform is unchanged. Copper conductors carry a 250A continuous load with a 360A intermittent allowance up to a 32V DC maximum, and the dial still offers the familiar four settings: bank 2, both banks combined, bank 1, and full OFF. Starting draw, house loads and a complete shutdown all remain within the capability of one switch.

The yellow housing keeps the isolation point easy to find in a dark locker, while the key barrel means the setting cannot drift or be changed by a passer-by. For fleet operators the practical benefit is straightforward: the supervisor keeps the keys, and the master circuit stays exactly as it was left between shifts.

• Key-operated dial — nothing changes without the key, so unauthorised switching is blocked.
• Copper conductor path — lower resistance and cooler terminals than plated steel contacts.
• 250A continuous / 360A intermittent — covers cranking bursts and heavy accessory loads at up to 32V DC.
• Four detented settings — 2-ALL-1-OFF for bank selection, combined output or complete isolation.
• High-visibility yellow body — quick to locate inside a battery box or engine locker.
• Water-resistant moulding — built for spray, humidity and fuel vapour in marine spaces.
• Familiar footprint — same 14 x 5 x 5 cm body as the standard version, so it replaces an existing switch directly.

• 1 — bank 1 feeds the circuit; the everyday setting for running from the start battery.
• 2 — bank 2 feeds the circuit; used at anchor when domestic loads run off the house bank.
• ALL — both banks joined for a cranking boost or to let one charger fill both batteries.
• OFF — all circuits isolated. Remove the key here and the installation stays dead.

• Isolate both batteries and disconnect the negatives before any wiring begins.
• Mount the body on a flat, rigid surface, checking that the key barrel clears nearby fittings and the dial sweeps all four positions.
• Run bank 1 positive to terminal 1 and bank 2 positive to terminal 2; take the load or starter feed from the common terminal.
• Terminate every cable with ring lugs and torque the stud nuts firmly — loose joints are the main source of heat at an isolator.
• Test each position with a meter, then remove the key in OFF and confirm the circuit cannot be re-energised.

• Boats and yachts — master isolation where a berthed vessel must not be switched back on by others.
• RVs and campers — long-term storage with the body still accessible to staff or family.
• Cars, 4x4s and trailers — anti-drain and anti-tamper isolation for vehicles parked off-site.
• Fleets and plant — supervisors retain the keys so operators cannot leave the master circuit live between shifts.

• 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.