Power Up

Fuse Box

 Blue Sea Systems ST Blade Fuse Block -- $42

    When I bought the Maxoak Bluetti EB240 solar generator, I was of the kind that such a device would enable me to dodge the more complicated wiring systems I had seen in van build videos.  Those had me daunted.

    So, I figured that I'd plug my AC things into powerstrips or extension cords and the into Bluetti's two backside outlets.  Actually, I still think that would have worked -- within the limits of the 1000W inverter, of course. 

    It was the DC situation that was the fly in the road, bump in the works, wrench in the monkey ointment.  I looked into multi-outlet DC extension cords, but quickly figured out that very few DC gizmos actually have those cigarette lighter type plugs.  When Hobo of Hobotech filled me in on the need for the converter and fuse box, it was time to do some research and learn some more stuff.

    All you need to know about the DC converter can be found by clicking the button marked "DC Converter".  The fuse box warrants its own section.

    I noticed that the term "fuse block" was often used, as was the term "negative bus." 

    Well, if you look at it, the word "block" makes sense.  The fuse "box" is more of a household term, for when you actually have a metal box mounted on your wall.

    The "bus" part of this one was a bit more of a puzzle.  I still don't really know where that came from.  Maybe because they are all lined up like seats on a bus?   I think I might have even read that somewhere.

    All of the positive terminals are on the top -- those double rows of three on each side.  All of the negative terminals are lined up on the bus on both sides of the lower 2/3 of the unit.  I was surprised that the positive and negative terminals did not have to be aligned.  There was no P1 and N1 or P11 and N11.  For my own sake, in an effort to keep it all from becoming a maze of wires, I did try to match them up in a logical way.  Upper-top left terminal holds the positive (red) wire and lower top-left terminal hold the negative (black) wire of

    I created some plastic labels at work and affixed them to all the wires, identifying the device and the +/-.  I also printed a chart on card stock and taped it to the floor of the cabinet, right in front of the fuse box.  Everything is correctly labeled. 

    The fuses all live in that lower part of the block as well.  I gotta admit that I'm still figuring those little suckers out.  So far, I've used a 15A fuse for everything.  I'm sure I could get away with 10A or even 5A ones for this or that, but I don't want to guess wrong and blow it.  Not a big deal if I do, really, since I have a big box o' spares.  Also, since the fuse block hangs at eye-level in the upper cabinet, it is easy-peasy to get at and to work with.  Certainly one of the best decisions of this Blue Maxx Project was to NOT keep the electric HQ under the desk. 

    But I don't know enough about fuses to make an informed choice.  I'm not at a point where I can look at a device and pin an amp value to it.  And that info isn't exactly stamped front and center on them.  Well, does it hurt anything to use a 15A fuse when all you need is a 5?   Well, Google found me the answer via DCN Electrical:

Fuses are one of the most important utilities in your electrical system.  Fuses are designed to protect the electrical wiring and your appliances from too much current flow that may result in overheating and consequential damage and in extreme cases, fires.

Electrical fuses trip or open the circuit when an excess of current is fed into a system. By safely burning out when too much current flows through, fuses prevent the wiring from becoming too hot.

A fuse contains a strip of low-melting-point alloy enclosed in suitable housing.  It is connected ‘in series’ with the circuit it is there to protect.  Due to the fuse’s electrical resistance, the alloy strip in the fuse is heated by an electric current; if the current exceeds the safe value for which the fuse was designed, the strip melts and breaks, opening the circuit and stopping the current.

    So, the short answer is, yes, it can be because if too much power gets to the device -- exceeding its amperage rating -- the device could freak out. 

    I reckon now I need to go out to Maxx and deduce the amp ratings for:  the MaxxFan (5), the 3 sets of puck lights (0.25 each set of 6), the USB-powered fans (1), the USB-powered speakers (1), and whatever else I might be forgetting.  I'll let you know what I find out (see parentheses).  I think I can scale down my fuses to 5's.  Maybe keep a 10 for the MaxxFan?

    This is further complicated by what wire you use.  And, that will be discussed in the section cleverly entitled, "Wiring."