DIY CAMPER ELECTRICAL SYSTEM FUSE PLACEMENT

I have one of my wiring diagrams here and it already has fuses in place and I felt like it was going to be easiest to show where the fuses need to be in a system and then explain why they are where they are now in this video I'm going to be using the term fuses and Breakers interchangeably because they're both just forms of over current protection the two most important things to understand when trying to determine where a fuse should be in a system is which direction is the power flowing and also how much power potential could be flowing through the wires so the batteries are always going to be the source it's considered the source of unlimited power if you will because if we short-circuited a battery Bank it could flow a lot of amps you know depending on how big of a battery Bank it is what type of batteries it could be thousands of amps if you short-circuited large wires directly off of the battery bank so that's where we consider our source of unlimited power and so we always want to be looking at which direction the source of unlimited power is going so for this system you know power is going to be flowing out of the battery Bank along this positive and along this negative line going to our Lynx distributor which is then sending power to and from our various loads and Chargers now the fuse it really should be as close to this positive battery terminal as it possibly can because this battery bank is the source of unlimited power and if we short-circuited these wires right here these two wires the positive and negative coming off of the battery bank there's going to potentially be let's call it a thousand amps flowing from this battery Bank we need that fuse to be in place to protect that short circuit event similar to in here inside of the lynx distributor which is holding all the fuses for all of these wires coming out to our inverter charger and our DC to DC charger and our solar charge controller each one of those positive wires is protected by a fuse that's in the lynx distributor let's talk about the solar charge controller for example our source of unlimited power is the batteries which is feeding the lynx distributor the lynx distributor can then be considered the source of unlimited power because it's being directly fed by the battery bank so these wires that are going out to the solar charge controller if a short circuit happens right here on these wires going to the charge controller the source of unlimited power is going this direction through this fuse that's protecting those two wires and this fuse will blow in the event that these two wires are short-circuited that would cut flow up flow of power off from the battery Bank and that's the same concept on the inverter charger as well as the DC charger here with the other fuses in place there if we follow these lines up to our DC fuse block to our 12 volt DC loads like our fans our lights USB Outlets all that kind of stuff we have the fuse in here and the lynx distributor that is going up and it's protecting these two wires from a short circuit event now inside of the 12 volt fuse block there's going to be even more fuses because every time we go down in wire size most of the time it needs a fuse I would say like 95 percent of times it needs a fuse so we're going from 100 amp fuse here protecting six gauge wire with 105 degree insulation rating and that had that that can deliver more power to this entire fuse block now each one of these circuits going off of the fuse block it needs its own fuse because this fuse here is too large to protect the let's you know potentially 16 gauge wire that we need to run you know just two or three Puck lights so there's fuses in all of these since that will protect from the unlimited source of power way back here at the battery Bank so that's the concept for the source of unlimited power you know the maximum power potential of the battery bank now let's talk about current limited devices for a second and switch gears and where it kind of gets confusing is the direction of chargers so power is going to be coming out of the Chargers through the lynx distributor back to the battery Bank to charge the battery bank that's on the charge controller that's on the DC to DC charger if the multi-plus inverter charger is connected to shore power and is charging the battery Bank all that power is going to be going this direction through these fuses and then back to the battery bank now on the source of unlimited power the fuse should be as close to the source of unlimited power as it can be now the opposite direction these wires are ultimately unprotected whenever it whenever it comes to being a charger okay let's kind of explain why that's actually still safe the fuse is on this end for our solar charge controller and the charge controllers really only going to be pushing power One Direction it's only going to be pushing power this direction whenever it's trying to charge the battery bank but this fuse doesn't protect this wire from a short circuit event if the power is Flowing here if there is a short circuit that happens on these two wires this fuse will blow that will cut that will cut power from the battery bank and keep you know a thousand amps from trying to flow to that short circuit but there's still going to be power flowing this direction and that's just how it works and there's really no way to protect against this let's say for example this is a 30 amp charge controller that's going to flow 30 amps along these two wires back to our links distributor back to our battery Bank if there's a short circuit that happens here and this fuse blows power is still going to be flowing this direction at a rate of 30 amps and is going to feed 30 amps to that spot in the wires well that seems kind of dangerous right so you know I mean that short circuit could potentially heat up and yeah it's absolutely true but there's no way to protect against that what size of fuse would you use there on this end of the wires so that the 30 amp charge controller could flow 30 amps of power under normal operation but also protect against a short circuit event where it's going to try to flow 30 amps of power you can't because the short circuit amount or the short circuit current coming this direction in the normal operation current are the same so there's no way to protect against one while still allowing the other one to function improperly and so there's no way to protect these wires against a short circuit event from the current limited device and this is accounted for an abyc the only way to really protect these wires and from a short circuit event on this side of things is to honestly just like make sure that you have good workmanship in your installation and make sure everything is uh you know it has protection from edges or anything sharp everything's tied up nice and neat so that it's not rubbing on stuff and there's really no chance to have a short circuit event on these wires let's take a step back and talk about what is a short circuit event well in our case here we're talking a short circuit event is where a positive and negative wire come in contact which allows power to just flow freely from the battery Bank it will flow as much power as is available the short circuit will flow as much power as is available to it so if it has a thousand amps it's going to try to flow a thousand amps if it has 30 amps available to it from a charge controller it's going on at the flow 30 amps so a short circuit event could happen if you you know touch a positive and negative wire together but you know just don't do that first off but you know more often than not when we're talking about an installed system it could be whenever the two wires run over like a piece of metal and they rub and over time that piece of metal eats into the insulation of the wires and contacts the copper inside of the wires and then that wire and then that piece of metal just becomes a bridge between the positive and negative wires and as far as distances uh from you know the different components and stuff like that that the fuse can be on the wire um abyc generally says that should be seven inches it has a few exceptions in the standards uh but the general rule is they want the fuse to be within seven inches of the source of unlimited power if you will that can be extended if the wires are in sheathing or in some kind of like enclosure or something like that but seven inches is the general rule but having the fuse as close to the positive terminals or in on the actual bus bar itself is always going to be the best way so how about Breakers and fuses for Shore power well we have this short power cord connected to a campground power pedestal or you know the just the standard household Outlet at your friend's garage or something like that and it's going in feeding into the multiplus and you'll notice that there's no Breakers or what or fuses or anything like that on that entire wire going from the outlet all the way to the inverter charger and the reason that is is because there's a breaker inside of the shore power pedestal or there's a breaker in the breaker box that's protecting the outlet that you're plugged into and it's the same reason why there's no Breakers or fuses whenever you plug in a coffee maker or something like that it's protected in the wall at the source of power which is the breaker box now there's a few different rules and considerations depending on which standards you're following that says you may need to have a breaker on this wire here coming from the inlet to the inverter charger but just kind of depends on the jurisdiction which you're in so always you know pay attention to the standards on where you're building now for solar array wiring now there's no over current protection in this particular wire for this solar panel because it's not needed now solar array wiring is actually significantly more confusing than all of this and I have a specific video covering just solar array wiring so we'll link to that in the video description so you can go check that out if you need to and lastly for fuse sizing well we're not going to talk about sizing in this video because I also have a video about that specifically and you know all of my diagrams and all of our kits in our store have the proper fuse sizes built into them or on the actual diagram but if you're trying to you know design your own system I've got a specific video and a calculator that'll help you figure out the proper fuse size for whatever you've got going on and that's all for this video and I hope you found it helpful we'll see you next time

Channel: EXPLORIST life - DIY Campers

Views: 27,464

Keywords: explorist, explorist life, explorist life electrical, explorist solar, explorist life wiring diagram, explorist.life, explorist life solar, explorist life blog, diy campervan, diy camper van, do it yourself, do it yourself camper van

Id: 5pHmjatMkvs

Length: 11min 16sec (676 seconds)

Published: Sun Jan 29 2023