250A Brass Blade Battery Disconnect Switch Compact Housing Knife Blade Battery Isolator for Car Truck Boat RV

Two switches, one set of numbers. The MT142D is a 250A, 12V–24V knife blade battery disconnect with the same brass blade and plastic base as the MT142 — built in a different housing, because battery boxes are not all built the same way.

If you are choosing between the two, the question is not electrical. It is whether the body, the fixings and the swing of the lever clear the box you have. This page is about that decision.

• The numbers do not move — 250A maximum, 12V–24V, brass blade, plastic base. A buyer switching between the two models keeps the same current margin and the same cable sizes.
• What does change is the envelope — the housing moulding, the fixing footprint and where the blade sits relative to the terminals. That is what decides whether a unit drops into an existing battery box.
• Same wiring diagram — two cables, one in and one out. No additional studs, no change to the fuse layout, so a drawing issued for the MT142 still describes this unit.
• Lever travel matters — measure the arc the lever needs, not just the body. A compact body in a deep box can still foul the lid on the swing.

1. Measure the box, not the old switch — old units sit where they were forced to fit. Take the actual internal width, depth and lid clearance.
2. Trial fit with no cables on — offer the switch up dry. If the fixings line up but the studs point at a bulkhead, you have found the problem now rather than after crimping.
3. Plan the lug direction — ring lugs need to sit flat on the stud. Side-loading a brass stud is how bases crack.
4. Cycle the lever five times — full open, full close, five cycles before the battery is reconnected. The blade should land square every time.

• Supply continuity — two housings in one range means a customer is never stuck waiting for a single moulding to come back into production.
• No re-engineering — a body change is not a circuit change. Panels, drawings, cable schedules and fuse ratings all stay as they are.
• Stock for older boxes — vehicles built years apart have different battery compartments. Carrying two shapes covers both without a bespoke bracket.
• One specification to quote — sales can quote either body against the same datasheet, which keeps written offers consistent.

MT142D, knife blade battery disconnect switch, brass blade on a plastic base in a compact housing, 250A maximum, 12V–24V, manual lever. There is no minimum order quantity: single units, samples and mixed containers are all accepted, with pricing quoted against quantity and packing. Standard production takes 30 days from deposit, T/T or Western Union, 30% down and the balance before shipment. Carton packed; pallet lots quoted separately.

Send a photo or sketch of your battery box with the internal dimensions and we will tell you which of the two bodies fits. No minimum quantity required.

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