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I an trying to rebuild my dash/ fuse panel/ switch board.
where is a good source for quality components without breaking the bank. would a boat store be overkill. i stripped and fuse panel with resettable breakers{ all still mounted} out of a newer international truck im planning on using. sound acceptable? new selenoids from napa.. their switches are pricy. or maybe im just not used to buying electrical parts.
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My brain hasn't been hitting on all cylinders this week, so I've hung back on this one for a while.
Resettable breakers - GREAT! Small planes have been using them both as breakers and sometimes on/off switches for years. I would like to build my control panel using them when the time comes.
In my experience, fuses blow a little faster on short circuits than breakers, but then you have to find out which one blew, and find a replacement. Self-resetting breakers can keep restoring power to a short until the wires heat up and the bus burns. Resettable breakers can just be reset, or if there's a real problem they can be left popped until you can fix the problem. As far as us re-using old ones, do a visual inspection first - no rust or carbon traces that would indicate past water entry or overheating, fire or sparking. Try the mechanical action and make sure the clicks feel positive, and not mushy. Measure them with a sensitive ohmmeter (down to single digits, tenths or hundredths) if you can. Make sure any high reading you get isn't poor contact with the meter leads.
With switches, circuit breakers, etc, wherever you find them, make sure you get ones that are
DC rated. It seem to me that switches work harder at DC. I would suggest using a 50% reserve rating, such as using a 20-amp DC switch for a 10-amp continuous load instead of a 10- or 12- amp one. Buy or salvage good ones, most of the stuff at Radio S _ _ _ _ will self-destruct under heavy use, maybe use one to run a relay coil but don't power headlights with them. (Side note: our camping trailer produced by a major stick & staples RV maker has a 7-amp AC rated switch powering all the DC loads except the patio light - up to 18 amps. When it burns out after the warranty expires, it's guaranteed to get service work for the dealers.)
Consider this image:
Electrical circuits are like circle dances where everyone holds hands and makes steps. DC circuits always flow in one direction, all the dancers (electrons) will go all the way around the circle, maybe several times around if the dance lasts long enough. AC circuits are like a dance where you take one step to the left, one step to the right, one step to the left, etc. No matter how long you dance, you are still pretty much where you started. 60 Hz AC reverses 120 times per second, 60 steps to the left and 60 to the right.
Now imagine there are too many dancers for one room. Half the dancers line up out the door to the next room, where there's a little window back into the first room. The last dancer in each room joins hands with the other by reaching through the window. The AC dance goes on uninterrupted, one step to the left, one step to the right, hands through the window. The DC dance has a problem. The end dancer reaches the window, and either climbs through it or the dance completely stops. If the dancers can climb through the window, both they and the window get scraped up in the process, and the dance slows down. What you need is not a window, but another door.
With AC circuits, due to capacitance if there is a barrier that blocks electrons from crossing, but allows the electrons on one side to cause equivalent electron motion on the other side of the barrier by magnetism, the circuit can work. With DC circuits, the electrons
must cross the barrier on their long journey from the negative post of the alternator or battery to the positive post. In theory, they may have to travel the entire length of the bus.
So, if you have a cheap switch with poor contacts, tarnished or burned contacts, or weak springs, it might work acceptably in an AC circuit by inducing alternating electron motion across the poor connection, but the same switch will heat up and fail if used on DC where the electrons all actually have to cross.
Now, maybe my explanation won't hold up to proper particle physics analysis, but it helps me understand why I need good, clean DC terminal connections and high quality switches that are DC rated in order to get good, clean current flow. Good switches with good contact alignment, quality contacts (you can't beat gold) and strong, positive snap-action springs are worth the extra cost.