How To Make A Power Relay / Fuse Block | Automotive Wiring

How To Make A Power Relay / Fuse Block | Automotive Wiring


alright guys yall have been asking for this one so I am going to do it and that is the power relay block

100 Replies to “How To Make A Power Relay / Fuse Block | Automotive Wiring”

  1. will this work for off road trucks? like pods, light bars etc? will the 40A relays be too much? This is awesome btw thanks !

  2. How to I connect this to my ignition switch? I dont want it to be constantly powered only with switch on. 1971 el camino

  3. 🤔 why common ground, most instances ground activating is better. Especially if you want more professional wiring.. yes building a car you are going to have your 12 running everywhere that you can “tap” into. “Tapping” into wires is not professional, and makes the all so fun game of “find what’s wrong” fun… only professional way to do it would be to run a positive from your central circuit, to the switch and would have to go back,

    Or ideally you’d want one nice block where everything is right there, fused and circuits all isolated. You want it that way, you don’t want to run your trigger for a switch from a random constant around, ex from like the radio. That block should have a constant, acc, and on terminals, for most things you would only have to run one wire out because ground is everywhere. If there is anything that gives off plus activation sure you can use it because again one wire, it’s outputting + and you don’t have a choice in that, it seems you are trying to make your job easier but in reality you’re not, and making it difficult for future people who may need to find what’s wrong.

  4. I think of the process like a TV remote. You sit in the big chair (drivers seat), you hit the power button on the remote(headlight switch), The TV comes on (headlights come on). No where in that did the 110v cable connect to the remote in your hand. It goes from the wall to the TV. You triggered a relay that connected the TV to the wall plug, turning it on. The switches on your dash are like little remote controls and the relays are THE REAL switches that turn shit on.

  5. I know this video is from a few years ago but would there only be one circuit breaker (ie between panel and battery) needed or should you run more than one?

  6. man, I've been trying to figure this out for two weeks. I'm stumped. How are you getting power to your relay white wire (86 – 85 black) with a switch located on the dash to energize the RELAY coil, which moves electro mag switch from 87a to 87 that closes the power to pin 30/pin 87 to activate your accessary?

  7. Sir when you say I’am going to run these yellow wires over here and red ones over here could you tell me what # that is on the relay???😁

  8. Curious if the type of fuse panels in any car are similar. Its hard to tell because of a lot of plastic paneling/molding around them (hard to see the screw down terminals in manufactured cars) . But if there like the ones you used in this video the install of the different gage wires is pretty much screw down terminals. Similar to the ground and white wire bus terminals in a home breaker box. Though i think there is a difference between the hot rod or hobbiest cars to the ones mass produced still…the fuse boxes just seem different perhaps they uses manufacture specific crimp on terminal ends / connector inserts into back of fuse box still a little confused.

  9. Also how are you tieing the 10 way fuse block to the bigger gage 2 , 6 , 8 gage battery wires you only show an important part of the entire electrical system of a car your missing the battery cables to fuse block to your 10 way fuse block. And any fusible links , circuit breakers you add. I have pretty good idea how it goes now but like to see the complete wiring from battery cables to the 10 way fuse block you created/addon as well.

  10. Love this video, will definitely refer to this! One thing was concerning me however, is a standard car battery capable of handling up to four different LED light bar connections?

  11. At 11:30 you mentioned things like this make you look like you know what you're doing… Everything except for the soldering part. Totally no needed with the proper crimp. Definetly wouldn't solder the ring terminals to the distribution block either.

  12. Nice job! I do prefere the panel mount Hella relay sockets though because you can mount those to you panel and then insert your relay. If you ever need to replace the relay, they are replaceable without having to unscrew anything.

  13. So what do you do if you want to use ground to tiger on the relay?
    I use ground to turn on my relays because vehicle has ground everywhere and if it shorts to ground no blown fuse and almost half the wiring.

  14. Do you have to run a seperate ground out of each relay? Or can they be just stacked on the same common ground? Also if I would want to run switched a d constant power could I do the same thing with this setup? Thanks

  15. Just a question, but why not run a single fused power to the coil on the relay from the fuse block? Then all you have is a single wire to your switch to control the ground side of the coil. Basically you control the ground with the switch, instead of the power. Then any shorts in the control side result in the relay being on, instead of arcing and blown fuses…

  16. Where 99% trying this will get it wrong is proper wire size to match correct fuse/breaker. If this is mismatched your wire could become the fuse/breaker. Seen this time after time. Great video my friend!

  17. Sorry to sound like a newb; does this basically create a central point to hook up multiple accessories (lights, etc) for a vehicle?

  18. amazing video, just one question I'm begging you to answer. The switches provide power to close the relay but where would the switches get power from. I was thinking the battery but then what would be the point of the relays, you could just have the power go straight to the switch after the fuse.

  19. Was about to install my newly built relay board (just like yours) and discovered I don't know where "both" my toggle switch ends connect to….help!?…do they "both" go to the switch side of the relay board?

  20. I have been all over the interwebs searching trying to figure out how to wire up a power windows conversion and add electronic door locks to my standard truck. thanks for the educational video.

  21. You are amazing. Learned a great deal in just a short time. Will put it to use on my 67 Bonneville. There are just too few circuits for today's gadgets.Really need to upgrade. Thanks for sharing.

  22. Perfect Video! No "blah, blah, blah", no BS, clear, concise & straight to the POINT! Even went out of your way to list all parts needed to build this! What else could you ask for?! Thank You!! #AmeriCuh

  23. Might I suggest you using rivets for the mounting of the relays and power distribution blocks to eliminate the need for long screws sticking out on the back side, even plastic rivets if plan to be making changes. They are easy to cut, cheap to buy and look clean. Other than that, extremely nicely done.

  24. I had a question about a 5 pin relay. the relay for my fans is 4 but my fuel pump kit is 5. is there a suggestion for the 5 pin relay?

  25. great video and very professional end product. If I might make two suggestions to improve the final outcome if only marginally, first I always use marine grade awg rated wire it is tinned copper and will not corrode in normal automotive use and only costs a few cents more. Second I use aviation style ratcheting crimpers they work much better and do not require soldering which will prolong your wiring life by not removing flexibility from the wire.

  26. I did something similar for my motorcycle and all the addons for it. I added another relay for the main power so the whole panel is switched to ignition switch in run position…. used a heaver power relay for that one. Well done!! Nice and compact. Variant to this would be getting ‘marine grade ‘ parts which are more water and corosion resistant… but more $$ too…

  27. thanks for the video, i wanted to ask as a switch also needs power would this connect to the other side of the fuse block? so in effect a horn for example would need two fuses one to the relay and one to the switch.

  28. That looks really good. Nice job – simple neat and cheap! I LIKE IT! Just one comment: it looks like your "heavy" wire is no bigger than AWG stranded #10 (?). That wire will most likely "burn" if it shorts out directly to ground between the 300A breaker and the fuse block . Based on the NEC, probably the breaker would be 80A or less to protect #10 if its about 4' from the breaker to the fuse box. At 300A you are talking about AWG #4.

  29. Why didn't you connect the yellow and white from each relay side by side, ie 4 matching pairs? Your way it's easy to get mixed up!

  30. great tutorial – thanks. question: does the relay do the same thing as a fuse? to use both would be overkill to connect say a light bar?

  31. 300 amp relay is for about a 1/0 wire. Good for a rear mount battery cable. As a side note, make sure you always use the proper gauge wire for the amount of current you're going to be providing. Sometimes people run too small a gauge wire, for example, to power electric fans and they wonder why the fuse always blows. You can buy something like this on Amazon if you do not want to build it yourself as well. Forgot to say, turned out great! Well explained.

  32. Thanks for video. I've never seen these breakers here in Russia, we're use 70/100/150A PAL type fuses instead. It's cheaper. And – I didn't like the way you attaching relays. If you will need to replace one of them, it would be pretty difficult. It is better to buy some common relay mount which you can attach to base, and you can put relays in and out of it easily. Sorry for my poor English, hope you understood))

  33. so one issue with the breakers is they are harder to find in lower voltage lower amperage.. it's better to use fuses for 95% of automotive application. if you don't know why a relay is better in some situations its because a switch can't hold high amperage. one example.. some wise guy put a 160watt light bar on a truck ran through a 20amp switch, on top of that used too small Guage wire. this almost burned the truck down on top of all of that the circuit wasn't even fused! wire safe my friends!

  34. Nice job. I am a big fan of neat and tidy and organised; it makes fault finding easier and shows forthought and planning. I actually thought that the fuse needed to be between the load (switch) and the power. Doesn't your fuse block only blow a fuse if the relay blows? What happens if the horn (light or whatever) shorts – is it fuse protected? Thanks.

  35. I have a suggestion, sir. Is that power wire coming out of the 300A breaker 8AWG? From the video, that's my best estimate. A 300A breaker can't protect a wire that small under all conditions. You should up the wire size to something like 1AWG or use a smaller rating on the breaker. You need to understand the behavior of the breaker in order to be certain. Wire insulation type matters too. Some types of wire insulation such as PVC will burn or melt at lower temperatures than insulation types like cross-linked polyethylene (GXL/SXL/SAE J1128) or Teflon.

    You said there would be fuses for the branch circuits. The wire size should also be chosen based on the fuse rating. You can always use a larger wire with a smaller fuse if you wanted to wire up everything using one wire size. That's more costly, though. Anyway, have a look at the published data from Littelfuse or another reputable manufacturer for recommended wire sizes and insulation types for each rating. Don't use knockoff foreign-made fuses. They don't work. You save a little money, but they are not precisely calibrated to respond to all overloads like fuses manufactured for OEMs do.

    Best of luck!

  36. This is awesome.
    I'm about to get my automotive electrical done at school and I'm going be adding lights on my 4runner. I've only ordered one light and everything else to go with it so far.
    After watching this I'm leaning more towards this setup rather than just screwing the relay to the side of the fuse box that's already in my car. This also looks a lot better than just a fuse harness dangling about too.
    With this setup you can always add more if you have only one circuit going through it. Thank you for the video man! It looks great!

  37. Question about all the black wires going to a common ground. I've seen this done two ways: One, common ground to the chassis. Two, common ground running back to the battery negative (which is I think how sPODs are recommended to be wired?). I'm building one of these to install in the rear of my Jeep, and trying to determine if I should run just a heavy gauge dedicated power wire back to it from the battery, or also a heavy gauge dedicated ground wire back to it from the battery as well. Thoughts?

  38. Does the relay panel have to mounted on plastic? Is aluminum okay to use, or is there a risk of shorting out? Love your channel. Very informative. Thanks for doing your videos.

  39. Now that's the most professional wiring. Very clean, outstanding job, great work much respect, thanks for technics.

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