Re: 12 V recepticle
OLMPILOT - AWG 10 is big stuff that you may not need to pay for and may never use. Depending on its size, you might be ok with the wire you have. You should check your inverter and your spotlight to see how many amps they draw. If you have wiring appropriate for 15-amps and protected by a 15-amp fuse, you will not have a problem with over-current in that conductor.<br /><br />[EDIT] Oops! RICK I just read where you said you are coming off the VHF for the receptacles power. No good. VHF needs its own, clean source or power. Nothing should share its wiring.<br /><br />Fwiw, wire can sustain more current than its rating for two reasons; (1) there is a mandatory (for approval) safety margin built in, (2) failure is determined by exposure to over-current for a period of time relative to the amount of over-current. And then theres something called in-rush. More on that below.<br /><br />Here is what you can to do and it wont take long at all
<br /><br />(1) Determine the maximum amps that you will be pulling through that plug. Look on your spotlight and inverter. Each should have a label either affixed or molded somewhere into the plastic housing that will indicate the amps. Often is it near the area where the power cord enters into the device. Whichever number is bigger, round it UP to the next closest increment of 5-amps. Ex: if your spotlight uses more and is rated for 5-amps, round up to 10-amps. If you inverter uses more and is rated for 14.2 amps, round up to 15-amps. You will have a ROUNDED UP value of 5, 10, or 15-amps and it should not exceed the receptacles current rating.<br /><br />(2) Determine the actual length of wire you need from the battery to the plug and round it UP. If the actual length is less than 10-ft, you can use up to 10-ft of wire without having an affect on the wire size. Anything longer than 10-ft can be rounded UP to the next 5-ft increment, i.e. 11-ft rounds up to 15-ft, 24-ft round up to 25-ft. You will have a ROUNDED UP value of 10, 15, 20, 25-ft, etc. This is the length of wire you CAN use, but shorter is better.<br /><br />(3) Go here:
http://www.ancorproducts.com/ Click on [Technical Info] then select [Wire Calculator]. Put in the length of wire you will be using and the amps (rounded up to the nearest increment of 5). The calculator will give you the minimum wire size you should use. See note below.<br /><br />(4) Install the wire (if needed) and a fuse that matches the ROUNDED UP amp value you used in the wire calculator (5, 10, or 15-amp fuse). Remember: if you are using an in-line fuse holder the wires into/out of the fuse holder must be the same size as the wire you are installing.<br /><br />(5) Label the fuse holder with the fuse size: 10-amp MAX
or whatever the appropriate fuse size is.<br /><br />NOTE BELOW: if you need less than 10-ft of wire for a 5-amp (or less) current, that calculator will tell you to use AWG 18 wire. You know better than that
you should not be using anything smaller than AWG 16. The flexing during boat rides may compromise the integrity of smaller wire.<br /><br />Other NOTE: you can blow a fuse if you try to operate something that has a high in-rush current (electric motor) from that power receptacle. In-rush is the temporary over-current needed to get things up and running. A 5-amp motor can have a very brief in-rush current of 15 or 20-amps. There are circuit breakers (and fuses) designed to allow a maximum in-rush for a specified period of time without tripping (blowing), after that they trip (blow). Those little 1¼ -inch, glass, fast-blow fuses that are common on boats do not allow for significant in-rush
thats why they are called fast. If you are going to operating something with a high in-rush you may want to rethink the fast-blow fuse in favor of one with an appropriate delay profile or even a breaker. When using a fuse to protect the wiring, never install a larger fast-blow fuse to support the in-rush current demand of an appliance.<br /><br />FARGINICEHOLE2 - About soldering: you can solder stuff but you should not have solder as the only means of maintaining connectivity. Crimping then soldering is popular but not necessary if you crimp correctly. Mechanical connections for conductors must be maintained for safety. The original query in this thread is an excellent example of why you should not rely on only solder. If that receptacle is installed with AWG 16 or 18 and the fuse is 20-amp to support that current demand; the wire will heat up just like in a toaster. Both the insulation and the solder will eventually melt off. You now have a very hot, unprotected power source with a 20-amp potential moving about freely with the motion of the boat making contact with who-knows-what under the dash or in the electrical panel. There is a very real chance of a fire
which will quickly become a whole-boat burning if not immediately contained. Fwiw, there hasnt been a lot of them but I have never seen damage from an over-current situation where the wire heated up, lost its insulation, and did not also melt the insulation off of other wires and the thermoplastic of terminal blocks and whatever other items are nearby. Everything is packed in so tight on a boat, you would be surprised at how much damage it can cause before it even gets to a flame. When wires are crimped and screwed down, they can be burned bare and other stuff damaged but in place and still functioning.<br /><br />MOD1 if there is an electrical problem it may not be a good idea to grab wires and disconnect them until you have disconnected the power. On a small vessel this may be the battery switch. If you are underway when the problem occurs, you should not necessarily shut down the engine so you will likely fry your alternators diodes unless you have a battery switch with field disconnect (AFD). When they are back in stock you can buy one here (Guest model 3101)
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http://www.iboats.com/mall/index.cg...ectric>battery>switch>guest&*******=990752259 <br /><br />ZMOZ I think it depends on the type of bulb. Some less powerful handheld spotlights require more than 10-amps. Xenon lights use less energy and the mega-cp spotlights tend to be xenon. You are also correct about sizing a fuse larger than the load but only when the fuse is used to protect the appliance, not the wiring. Thom's explaination above applies to this situation; using a fuse to protect the wiring, not the appliance...but you knew that.
