I had a dead short on a 20m-long 220v extension lead. We were building a chicken farm in Thailand and the temporary electric supply installed by the farmer/builder had no breaker, a straight 220v supply off one of the 3-phase supplies. It is absolutely terrifying, the whole building filled with dense brown smoke. It only stopped when the wire melted. I was too scared to touch the knifeblade switch and turn the supply off. I thought my whole investment was going to burn down. The scorch marks are still on the concrete floor today. I am a lot better-versed in electrical systems today than I was then, a lot of the information I got was from Jeff's videos. I'm still learning. Nice one Jeff, BTU.
I've been working through your video set and was most impressed with this one. Your explanation of how motors draw more current when fed with lower voltage is a topic that many techs do not understand well. You got me thinking about how I can better reposition my fuse locations to better protect the wire, in case of a proximal dead short between battery and present fuse location.
If you own a boat over 30 feet and you don’t take the time to review this video you’re asking for trouble. I don’t know who this guy is but no BS more like how to be as safe as possible how to avoid deadly fire aboard. So grateful for a video like this that doesn’t seem to have any particular ax to grind any particular product to sell!
I see you are strong in this. Would be thankful if you could help me with one more question. ''What is a consequence of low insulation in exciter coils of an alternator?'' Thank you in advance!
Thank you for your vids. It's a real pleasure to have so good quality information. I haven't heard if it is possible to start a 50 or 70hp engine with the house bank, in case of a starter battery death while we are at an anchrorage for example. I just have a look on the schema of my sailboat. There is a battery isolator and the 2 battery banks are on it. But there no fuse between the alternator and the batteries. Do you think I must add one on the Alternator, or is there a fuse in the alternator ? Thanks
Jeff, your electric /electronic videos are great! On the fusing video I have a question? I have large fuses between house bank and breaker panel, alligator and ACR, charger and batterie banks, and breakers. On breakers with only item being powered do I need fuse between breaker and the item ie vhr? On breakers powering multiple cabin lights thru a buss bar do I need a fuse? All navigation and cabin lights are led with 14 g wire, running lights 14g wire. On plugs used to charge phone's,laptop's, and computer running 12g wire do I need a fuse at tach plug or 1 at the bus bar? Thanks for taking the time to record and edit theses videos.
Great video thank you! I am currently working on the canal boat im building in Amsterdam and doing the wiring my self. I have a question though. I will be using only a switched panel with 4 switches(fused at panel). So Ill run a Fuse from the battery to the bus barr and then 4 fuses going to the switch panel (just after the bus bar right). And then the panel is fused as well. I did not see in your diagram that there has to be fuses after the bus bar, there need to be then four for eats wire right,? Much apreciated, Daan
Hi Jeff, thank you so much for your videos. I had a question on thermal breakers. You say that they are generally only used on motorised loads, but are there any reasons why we shouldn’t use them everywhere, considering they are more practical and less wasteful than regular fuses? Thanks
Great Videos you have :) I have one question: I have two motor on my boat, and consequently 2 batteries that are on use for the equipment's as well, I have a 1,2 all switch, and I would like to install a battery to use only will the equipment's, can you let me know the best way to do it. Thank you :)
Hi Great video , where would you use a class T fuse seen you refer to it in others vids thx i have a Victron 24/5000/220 Inverter charger Lithium bank 8x12v 200a set in in 4 pairs for a 24v bank , how do i work out the size of the class T fuse thx
On land, I was always taught that circuit breakers that trip will either start to trip under progressively lower load (becoming more and more of a nuisance) or start to trip under progressively higher load (becoming more and more of a risk). Is that the same in the marine world, and is that not affected by using the breaker as a switch? In other words, should I install a true switch in addition to the breaker to improve safety?
Your videos are fantastic, Jeff - thank you and PYS for putting these together. I have a question about Fuses vs Circuit breakers. From my distribution panel with circuit breakers, you mentioned in another video placing the fuse close to the appliance in this scenario. If my circuit breaker is 5A, and my appliance (say water pump) demands 3.75A, do I need to place a fuse on this line, and where - or would the 5A circuit breaker be enough? (Also a 100A fuse between battery and panel.) Does the circuit breaker protect the 14AWG cable, 30ft full circuit run, and the fuse protect the appliance, or is this unnecessary with a proper amped 5A breaker? Thanks for your help - looking forward to finishing my boat project and want to do it right! You're inspiring many of us budget, first time boaters to not be scared of marine electronics!
Since circuit breakers come in limited sizes (e.g. 5, 10, 15, 20, 25, 30, 50, etc...), we commonly have circuit breakers protect the wire to the appliance and then close to the appliance we install the exact fuse recommended by the manufacturer. Generally, to avoid nuisance tripping of the circuit breakers, size the wire and the circuit breaker to be able to handle at least 1.25 times more then the max expected amperage. The fuse near the appliance is sized exactly as per the manufacturer.
@@PacificYachtSystems Thank you for clarification, I can only imagine it is a good thing but wasn't sure if there were negatives involved. Thank you again 👍😁
From the question about the current going up as the voltage going down to the windless at around minute 14. When I was in automotive school, the instructor said that the resistance of an electric motor comes from the armature spinning. If you could stop the motor from spinning, you would be able to create a short to ground through the motor. I think this is how the amperage goes up as the voltage goes down, the low voltage causes a motor armature to spin more slowly and thus, the resistance goes down and the amperage increases.
@@PacificYachtSystems I would like to add something to help here. When a light bulb is measured for resistance (low voltage) then R is almost zero, but once connected to AC, R is not almost zero anymore (240). R value depends on the current going through resistors. Thats is why when the V drops, R drop and then Current tries to go higher, tripping the breaker.
@12:30 the reason that the the current increases as voltage drops on a motor but not a light bulb is that the motor is also a generator as it turns-its called back emf which bucks the input current. As the the motor slows because of low voltage (or excess load) the back emf decreases ,in effect lowering the apparent resistance and increasing current. The max a motor will draw is in the non rotating condition.This often called the "Locked Rotor" spec and exceeds the "normal" load current
I guess there is a limit to this, when the wire length is really short, then the place of the fuse becomes a "fussy" decision, no? ie: we have 20cm (8in) wire between the batteries and the DCtoDC charger. The fuse takes half of the length. (Small compartment on a small sailboat) Still learning here :) Thank you Jeff.
I have a combined charger/inverter Victron 12/1200/50 on a boat. Would a circuit breaker be able to break the circuit in case of too high current both to/from the battery or would I need a fuse?
If you got a battery one with like 10volts you can hook it to the dead one and then put the charger on them together for a hour and come back take the one that had some charge to it off if the one that was completely discharged is taking on charge it will charge on up but that’s a way to fool your charger and make it charge a battery that’s dead or bring one back however you wanna frase it !
Yep, you should because all the leads connected to the unswitched distribution should be fused, unless that circuit can be used for starting the engine.
GDay Teach 🍎 I’m still gathering information ℹ️ on relevant formatting\outlay, for my humble trailer boat. So, a question 🙋🏻♂️ ⁉️ { Quest ’for the’ ion 😸} 1 ) Is ‘combiner’ another description for DCDC Charger ⚡️ 🔍🤔⁉️ 2 ) how many benign insulation coats should an ideal marine cable have ⁉️ 3 ) What’s the Best marine cable brand, Good Sir ⁉️ 4 ) For a 115hp 2stroke, what’s the ideal exterior operational [onboard] gauge wire for In-between humble appliances eg; pot winch etc, Skipper/Teåcher ⁉️ I guess that last question 🙋🏻♂️ is “loaded”, pardon the pun..,😉👌🏼 As attempt to answer my own question 🙋🏻♂️ I Thankfully 😅 recall your previous tutorials on the importance of knowing the combined draw of existing & possible machínes/motors & converters • Merci Beaucoup 🙏 for your insight ✨☂️🌅 🌊
1) Battery combiner and DC to DC charging converters are similar but offer different ways of sharing a charging voltage 2) Make sure to choose marine rated wiring, it will have the correct wire insultation 3) Lots of good choices, as the many brands like Ancor can also be bought under names, like Vertex. 4) When choosing the wire, consider the max amperage and the max distance to your loads. As a guestimate, probably #0 to #2 wire size.
These are some great videos and have probably saved my arse more than once so far. I hate to be that guy... but opaque is pronounced oh-pake rather than oh-pack.
The argument on whether fuses are meant to protect wires or equipment is moot . . . fuses are there to, in the end, protect _you_ . . . wires and equipment and boats are replaceable.
