Size for fuse at the Batteries (2x 6v)
Hello and thanks to all in advance! I have a pair of 6v batteries and wanted to place a fuse at the batteries. My trailer is 30 amps and I currently have 6 gage cables. Also, would the fuse be att...
Forum Discussion
Fuse size is determined by the wire size (and type and installation) that the fuse is protecting. Recall that the purpose of a fuse is to prevent a fire due to the wire overheating from excessive current.
50A is a conservative size for 6 gauge wire; the NEC permits between 55A and 75A depending on the temperature rating of the wire. These guidelines are not immediately applicable to low voltage wiring (as the wire types are usually different), but do give a reasonable starting point. Often the 12V fusing is more permissive. At any rate, I'd feel entirely comfortable using a 50A, 60A, or even 75A fuse or circuit breaker in your situation.
The 30A AC inlet has absolutely nothing to do with this; the 120V electric system is quite separate from the 12V system. Likewise, the details of the battery are irrelevant; any 12V house battery could supply many times the current that the wire could carry safely. The fuse would be put in the positive line, as close to the battery as reasonably practical. The negative battery lead connects to ground directly. (If you have a battery monitor or battery ammeter, the shunt is usually placed in the negative lead.)
50A is a conservative size for 6 gauge wire; the NEC permits between 55A and 75A depending on the temperature rating of the wire. These guidelines are not immediately applicable to low voltage wiring (as the wire types are usually different), but do give a reasonable starting point. Often the 12V fusing is more permissive. At any rate, I'd feel entirely comfortable using a 50A, 60A, or even 75A fuse or circuit breaker in your situation.
The 30A AC inlet has absolutely nothing to do with this; the 120V electric system is quite separate from the 12V system. Likewise, the details of the battery are irrelevant; any 12V house battery could supply many times the current that the wire could carry safely. The fuse would be put in the positive line, as close to the battery as reasonably practical. The negative battery lead connects to ground directly. (If you have a battery monitor or battery ammeter, the shunt is usually placed in the negative lead.)
