{"product_id":"blue-sea-6004200-battery-switch-on-off-locking-key","title":"Blue Sea 6004200 Single Circuit ON-OFF Battery Switch - Black","description":"\u003cp class=\"nvn-hero\"\u003eThe Blue Sea Systems 6004200 is a single-circuit ON-OFF battery switch with a locking key, rated 300 amps continuous. It's sized right for an outboard rig or a small gas or diesel engine. Flip it on before you crank, flip it off when you tie up, and pull the key so nobody drains your bank.\u003c\/p\u003e\n\n\u003cdiv class=\"nvn-description\"\u003e\n\u003cp\u003eBlue Sea Systems builds electrical gear that survives the harsh reality of a boat, and the 6004200 is a clean example. It's a single-circuit ON-OFF battery switch with a locking key, rated for 300 amps continuous. That's plenty for an outboard rig or a small gas or diesel engine. Flip it to ON before you crank, flip it to OFF when you tie up, and pull the key so nobody kills your bank while you're off the boat.\u003c\/p\u003e\n\u003cp\u003eWe reach for a switch like this on center consoles and smaller cruisers where you want a proper main disconnect without a huge footprint. The case is built for surface mounting, and the breakout tabs let you run your cables in from just about any direction. So whether your battery sits below the console or back near the transom, you can route the wiring cleanly. The isolating cover snaps over the rear contacts and keeps stray tools, wet lines, and curious fingers away from live studs.\u003c\/p\u003e\n\u003cp\u003eThe studs are where this switch earns its keep. They're tin-plated copper, so they carry current well and shrug off corrosion better than bare brass ever will. Each stud takes a 3\/8 inch (M10) ring terminal, and the 7\/8 inch (22 mm) length gives you room to stack more than one cable terminal when you need to. Blue Sea's one-piece terminal stud design doesn't back out over time, which matters on an outboard boat that pounds through chop all day. Torque them down with the one-piece stainless flange nuts, add a lock washer, and they'll stay put. A dab of dielectric grease on the key and the contacts once a season keeps salt from seizing things up.\u003c\/p\u003e\n\u003cp\u003eOn the electrical side, the numbers are honest. 300 amps continuous, 500 amps intermittent, and a 900 amp cranking rating for 30 seconds. Maximum voltage is 48V DC, so it covers everything from a 12V outboard to a 24V or 48V house and trolling setup. For a boat running a single Group 27 or Group 31 starting battery, this switch is right in the wheelhouse. If you're pulling big sustained loads over 100 amps, like a large inverter bank, step up to a bigger switch. This one is sized for engine and main-disconnect duty, not heavy continuous house draw.\u003c\/p\u003e\n\u003cp\u003eThe locking key is the reason a lot of folks pick this exact model over the plain knob version. Trailer boats, rentals, and any boat that sits at a public dock benefit from being able to lock the battery off and walk away. Keep a spare key aboard, because the key is plastic and it'll snap if you force a switch that's gone stiff from corrosion. Mount it somewhere dry and reachable, give the studs a proper torque, and this little switch will happily outlast a couple of engines.\u003c\/p\u003e\n\u003cp\u003eOne install note from the field. If you're panel-mounting the key barrel through fiberglass, it wants a clean 1-1\/8 inch hole. Thicker glass sometimes needs a little filing so the key seats all the way and turns freely. Take your time on that cutout. A key that binds is a key that breaks, and then you're standing at the dock with half a switch.\u003c\/p\u003e\n\u003cp\u003eIt also plays nicely as part of a larger Blue Sea panel. Plenty of boaters run this switch alongside a Blue Sea fuse block for the branch circuits, then add an automatic charging relay when they move up to a two-battery setup. On its own, though, it's a straightforward main battery disconnect. One battery, one engine, one switch, done.\u003c\/p\u003e\n\u003cp\u003eBottom line, the 6004200 is a well-made main disconnect for the money. The tin-plated copper studs, the never-loosen stud design, and the lockable key are the details that separate it from a cheap parts-store part. If you want a clean, safe way to kill the power on a smaller boat, this is an easy call.\u003c\/p\u003e\n\u003c\/div\u003e\n\n\u003ch2\u003eKey Features\u003c\/h2\u003e\n\u003cul class=\"nvn-features\"\u003e\n  \u003cli\u003e300A continuous rating handles outboards and small gas or diesel engines\u003c\/li\u003e\n  \u003cli\u003eLocking key lets you shut the battery off and pull the key so nobody drains the bank\u003c\/li\u003e\n  \u003cli\u003eTin-plated copper studs carry current well and resist corrosion better than bare brass\u003c\/li\u003e\n  \u003cli\u003e3\/8 inch (M10) studs with 7\/8 inch (22 mm) length accept multiple stacked ring terminals\u003c\/li\u003e\n  \u003cli\u003eOne-piece terminal stud design never loosens over time, even under outboard vibration\u003c\/li\u003e\n  \u003cli\u003eOne-piece stainless flange nuts make safe, secure connections every time\u003c\/li\u003e\n  \u003cli\u003eIsolating cover protects the rear contacts from tools and stray wires\u003c\/li\u003e\n  \u003cli\u003eBreakout tabs let you route cables in from any direction for a clean install\u003c\/li\u003e\n  \u003cli\u003e48V DC maximum voltage covers 12V, 24V, and 48V systems\u003c\/li\u003e\n  \u003cli\u003e500A intermittent and 900A (30 sec) cranking ratings for reliable engine starts\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cdiv class=\"nvn-trust\"\u003e\n  \u003ch2\u003eWhy Buy from NVN Marine\u003c\/h2\u003e\n  \u003cul\u003e\n    \u003cli\u003eAuthorized Blue Sea Systems reseller, full manufacturer warranty\u003c\/li\u003e\n    \u003cli\u003eNMEA member and ABYC certified, advice from real boat techs\u003c\/li\u003e\n    \u003cli\u003eSame-day shipping before 3 PM ET on in-stock items\u003c\/li\u003e\n    \u003cli\u003eNY headquarters and Fort Lauderdale flagship retail store\u003c\/li\u003e\n  \u003c\/ul\u003e\n\u003c\/div\u003e\n\n\u003ch2\u003eFrequently Asked Questions\u003c\/h2\u003e\n\u003cdiv class=\"nvn-faq\"\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eWhat size battery and engine is the 6004200 rated for?\u003c\/summary\u003e\n    \u003cp\u003eIt's rated 300 amps continuous, which suits a single starting battery on an outboard or a small gas or diesel engine. It handles 500 amps intermittent and a 900 amp cranking load for 30 seconds. For big sustained house loads over 100 amps, step up to a larger switch.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eDoes it work on a 24V or 48V system?\u003c\/summary\u003e\n    \u003cp\u003eYes. Maximum voltage is 48V DC, so it covers 12V, 24V, and 48V systems.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eWhat ring terminals fit the studs?\u003c\/summary\u003e\n    \u003cp\u003eThe studs take 3\/8 inch (M10) ring terminals. The 7\/8 inch (22 mm) stud length gives you room to stack more than one cable terminal when you need to.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eCan I lock the battery off and remove the key?\u003c\/summary\u003e\n    \u003cp\u003eYes, that's the whole point of this model. Turn it to OFF and pull the locking key so nobody switches the bank back on while you're away. Carry a spare key, since the key is plastic and can break if forced.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eWhat size hole do I need to panel-mount the key barrel?\u003c\/summary\u003e\n    \u003cp\u003eA clean 1-1\/8 inch hole. If you're going through thick fiberglass, you may need to file the hole slightly so the key seats fully and turns freely.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eWill the studs loosen from engine vibration?\u003c\/summary\u003e\n    \u003cp\u003eBlue Sea's one-piece terminal stud design is built so the studs don't back out over time. Torque the one-piece stainless flange nuts down properly and add a lock washer, and they'll stay tight even on a boat that pounds through chop.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eHow do I keep the key and contacts from seizing up?\u003c\/summary\u003e\n    \u003cp\u003eA dab of dielectric grease on the key and the contacts once a season keeps salt spray from corroding them and keeps the key turning smoothly.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eCan I use it for a dual-battery setup?\u003c\/summary\u003e\n    \u003cp\u003eOn its own it's a single-circuit main disconnect for one battery. If you run two batteries, pair it with an automatic charging relay or a second switch to manage the banks.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eIs the isolating cover included?\u003c\/summary\u003e\n    \u003cp\u003eYes. The isolating cover ships with the switch and snaps over the rear contacts to protect the live studs.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eIs this the same switch as the red 6004?\u003c\/summary\u003e\n    \u003cp\u003eSame Blue Sea single-circuit ON-OFF switch with a locking key. The difference is the color, black on the 6004200 and red on the 6004. Ratings and mounting are identical.\u003c\/p\u003e\n  \u003c\/details\u003e\n\u003c\/div\u003e\n\n\u003ch2\u003eTechnical Specifications\u003c\/h2\u003e\n\u003ctable class=\"nvn-specs\"\u003e\n  \u003ctbody\u003e\n    \u003ctr\u003e\n\u003cth\u003eTitle\u003c\/th\u003e\n\u003ctd\u003eBlue Sea 6004200 Single Circuit ON-OFF w\/Locking Key - Black\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eBrand\u003c\/th\u003e\n\u003ctd\u003eBlue Sea Systems\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eManufacturer Part Number\u003c\/th\u003e\n\u003ctd\u003e6004200\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eUPC\u003c\/th\u003e\n\u003ctd\u003e632085600426\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eSwitch Type\u003c\/th\u003e\n\u003ctd\u003eSingle Circuit ON-OFF\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eColor\u003c\/th\u003e\n\u003ctd\u003eBlack\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eMaximum Voltage\u003c\/th\u003e\n\u003ctd\u003e48V DC\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eContinuous Rating\u003c\/th\u003e\n\u003ctd\u003e300A\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eIntermittent Rating\u003c\/th\u003e\n\u003ctd\u003e500A\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eCranking Rating (30 sec)\u003c\/th\u003e\n\u003ctd\u003e900A\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eStud Material\u003c\/th\u003e\n\u003ctd\u003eTin-plated copper\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eStud Size\u003c\/th\u003e\n\u003ctd\u003e3\/8 inch (M10)\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eStud Length\u003c\/th\u003e\n\u003ctd\u003e7\/8 inch (22 mm)\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eTerminal Nuts\u003c\/th\u003e\n\u003ctd\u003eOne-piece stainless flange nuts\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eLocking Key\u003c\/th\u003e\n\u003ctd\u003eIncluded\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eSeries\u003c\/th\u003e\n\u003ctd\u003eM-Series\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003c\/tbody\u003e\n\u003c\/table\u003e\n\n\u003cscript type=\"application\/ld+json\"\u003e\n{\n    \"@context\": \"https:\/\/schema.org\",\n    \"@type\": \"FAQPage\",\n    \"mainEntity\": [\n        {\n            \"@type\": \"Question\",\n            \"name\": \"What size battery and engine is the 6004200 rated for?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"It's rated 300 amps continuous, which suits a single starting battery on an outboard or a small gas or diesel engine. It handles 500 amps intermittent and a 900 amp cranking load for 30 seconds. For big sustained house loads over 100 amps, step up to a larger switch.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"Does it work on a 24V or 48V system?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"Yes. Maximum voltage is 48V DC, so it covers 12V, 24V, and 48V systems.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"What ring terminals fit the studs?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"The studs take 3\/8 inch (M10) ring terminals. The 7\/8 inch (22 mm) stud length gives you room to stack more than one cable terminal when you need to.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"Can I lock the battery off and remove the key?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"Yes, that's the whole point of this model. Turn it to OFF and pull the locking key so nobody switches the bank back on while you're away. Carry a spare key, since the key is plastic and can break if forced.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"What size hole do I need to panel-mount the key barrel?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"A clean 1-1\/8 inch hole. If you're going through thick fiberglass, you may need to file the hole slightly so the key seats fully and turns freely.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"Will the studs loosen from engine vibration?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"Blue Sea's one-piece terminal stud design is built so the studs don't back out over time. Torque the one-piece stainless flange nuts down properly and add a lock washer, and they'll stay tight even on a boat that pounds through chop.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"How do I keep the key and contacts from seizing up?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"A dab of dielectric grease on the key and the contacts once a season keeps salt spray from corroding them and keeps the key turning smoothly.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"Can I use it for a dual-battery setup?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"On its own it's a single-circuit main disconnect for one battery. If you run two batteries, pair it with an automatic charging relay or a second switch to manage the banks.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"Is the isolating cover included?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"Yes. The isolating cover ships with the switch and snaps over the rear contacts to protect the live studs.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"Is this the same switch as the red 6004?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"Same Blue Sea single-circuit ON-OFF switch with a locking key. The difference is the color, black on the 6004200 and red on the 6004. Ratings and mounting are identical.\"\n            }\n        }\n    ]\n}\n\u003c\/script\u003e\n","brand":"Blue Sea Systems","offers":[{"title":"Default Title","offer_id":44925488169053,"sku":"64358","price":27.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0299\/7266\/0317\/files\/64358XL.jpg?v=1787378387","url":"https:\/\/nvnmarine.com\/products\/blue-sea-6004200-battery-switch-on-off-locking-key","provider":"NVN Marine","version":"1.0","type":"link"}