Hey, step back for a second and think about serviceability. Personally, I don't care what you do. Three wires in a suitably rated terminal is fine. But, it may not be the best solution.

For sure. My initial question was I could do three wires into one but does anyone know better ways of doing this. I appreciate your help.

 

For sure. My initial question was I could do three wires into one but does anyone know better ways of doing this. I appreciate your help.

Please re-read my post about the piggy back connector. Yes, there is a better way, that lets you isolate the circuits, if needed.

 

The method I gave you for three wires together is the correct method. You can blunt cut the three wires and use an uninsulated butt connector or twist them together onone side, and run a single wire out the other side which will carry the total current of all 3 wires. Solder and shrink tube best method for this application. To replace your glass fuses, replace them straight across the board. 10A for 10A etc. Piggyback connectors are not recommended as they provide one more avenue for loose connections. If you look at OEM, you will not find piggybacks. Everything straight into the fuse block. Lastly if you are going to split up circuits, your fuse ratings and wire sizes are going to change accordingly. A 30A fuse should not be substituted for a 15A fuse in any scenario as it may allow more current than the wiring or component can handle. Good luck with your project.

 

I personally like the 8-way fuse block you showed in your sketch. That allows you to easily isolate individual circuits for troubleshooting, and you can do that with 2 wires/max in a crimp. Some of us here are probably old enough to remember the poor reputation British cars had for electrical reliability

 

I personally like the 8-way fuse block you showed in your sketch. That allows you to easily isolate individual circuits for troubleshooting, and you can do that with 2 wires/max in a crimp. Some of us here are probably old enough to remember the poor reputation British cars had for electrical reliability

Haha too right. Good old Lucas electrics on my mini. I’m sure you’ve seen some shocking British electrics over the years. Luckily I’ve only heard about them rather than have to deal with them!

The method I gave you for three wires together is the correct method. You can blunt cut the three wires and use an uninsulated butt connector or twist them together onone side, and run a single wire out the other side which will carry the total current of all 3 wires. Solder and shrink tube best method for this application. To replace your glass fuses, replace them straight across the board. 10A for 10A etc. Piggyback connectors are not recommended as they provide one more avenue for loose connections. If you look at OEM, you will not find piggybacks. Everything straight into the fuse block. Lastly if you are going to split up circuits, your fuse ratings and wire sizes are going to change accordingly. A 30A fuse should not be substituted for a 15A fuse in any scenario as it may allow more current than the wiring or component can handle. Good luck with your project.

Thank you once again. I think if I don’t go for the daisy chain connections I will be doing this so they all go into one connector. I agree about the piggybacks, that’s why I’ve been reluctant to settle on that method.

Please re-read my post about the piggy back connector. Yes, there is a better way, that lets you isolate the circuits, if needed.

Will do. Thanks again for your help.

 

Maybe you can also find a small screw terminal block that you can run the 3 wires to and then run 1 wire to the fuse block. That makes things very serviceable. Only downside is finding a place to mount the terminal block, but it be make for very clean wiring if you do find a spot for it. Just thinking of other options.

 

Maybe you can also find a small screw terminal block that you can run the 3 wires to and then run 1 wire to the fuse block. That makes things very serviceable. Only downside is finding a place to mount the terminal block, but it be make for very clean wiring if you do find a spot for it. Just thinking of other options.

Another good suggestion and one I hadn’t thought of. Mounting may be an issue but if I can sort that it’s another avenue so thanks for that.

 

Wait - have I missed something? You want to replace 8 fuses with 4? I don't think you'll like the results IF that's the case.

Take for example your 8 fuse diagram: You have one white wire of an unspecified gauge feeding TWO fuses rated (as you indicate) 15/20. Each individual fuse is connected to a single green wire. In your 4 fuse diagram you show the white wire connecting to a 35 amp fuse and two green wires tied together and going off to their individual circuits. That's got disaster written all over it.

Here's what I mean: You have a white wire of 12 gauge (assuming the size of the wire for example). That wire can handle about 20 amps normal service. You have a 35 amp fuse. If there's an electrical fault the fuse isn't going to blow, the wire will burn. Or here's another scenario: Your equipment which might require a 15 amp fuse may experience an intermittent electrical issue. If fused properly the fuse will blow and damage to the equipment will be limited or even mitigated. Not so with a 35 amp fuse. Your equipment will likely melt down and quite possibly burst into flames.

The automotive engineers designed it the way they did for a reason. With automotive design the two biggest factors are reliability and safety. By having individual fuses for each circuit both the equipment and wiring are protected from damage and possible fire. It's looking like you want to throw safety out the window in favor of a ticking time bomb. You may never experience an issue. However, in the event you DO experience an issue - the outcome is going to be bad in a very big way.

If I'm wrong - please clarify. If I'm right - please reconsider.

 

@Tonyr1084
He is not replacing 8 fuses with 4. See post #1. The original fuse box had 4 glass fuses and two sets of two spade connectors (16 total, apparently) for each fuse. The proposed new box has 4 modern plastic fuses and only 8 spade connectors (two for each fuse).

My suggest is and has been, don't change the original wiring, if you do not have to change it. We don't know whether it was designed with 8 "output" connectors for a reason. I assume it was. That reason may not be obvious now to the TS, but then, is that his area of competence? I can think of some reasons to keep the circuits separate, even if they share a common fuse.

 

Wait - have I missed something? You want to replace 8 fuses with 4? I don't think you'll like the results IF that's the case.

Take for example your 8 fuse diagram: You have one white wire of an unspecified gauge feeding TWO fuses rated (as you indicate) 15/20. Each individual fuse is connected to a single green wire. In your 4 fuse diagram you show the white wire connecting to a 35 amp fuse and two green wires tied together and going off to their individual circuits. That's got disaster written all over it.

I understand what you're getting at. But in your example, the existing white wire goes to a 35A fuse. Minimayfair is suggesting to replace that single 35A fuse with two 15A or 20A fuses in parallel, or maybe a 15A/20A fuse combination. Their total load, assuming everything was sized right to begin with, should be the same as the single 35A fuse was supplying.

Now if the two loads on the existing white-wired 35A fuse were unbalance, so that one drew (say) 20 amps and the other 5 amps, that would be OK marginally with the 35A fuse, but would not work with dual 15A or 20A fuses.

 

Wait - have I missed something?

Apparently I DID miss something.

He is not replacing 8 fuses with 4. See post #1.

Yes, I see where I went wrong in my assumption.

However, I'm still a little confused about the fuse ratings. IF there was an original 35 amp fuse then the wiring would have been big enough to support the current it might carry. This is where more (clearer) information is needed. Simply telling someone they're OK to stick a bunch of wires in a coke bottle without knowing the purpose or size or anything else that may be critical can be a big mistake. It's like suggesting to someone they test for lightning with their tongue. That CAN'T have good results.

In pictures posted he's shown both a 4 gang glass fuse holder and a 4 gang plastic fuse holder. I guess I got a little backwards on the way he was going, thinking he was going from 8 to 4. IF he's going from 4 to 8 (no picture of an 8 gang plastic fuse holder) then he's fine breaking the circuits out into individual circuits. As long as the potential current on any supply line does not exceed the wire gauge amperage rating.

Thought about editing my post but that might add to confusion. It's better to correct my comments here and go forward.

But if he's going to an 8 gang box then why does he want/need to splice wires together?

[edit] unless he's splicing the power source wires together. But then he could crimp two wires into the first crimp with the initial power wire and a jumper wire to the next fuse input terminal. Another double crimp and he could jump to the next. And the next and the next as the need may be.

 

Apparently I DID miss something.
Yes, I see where I went wrong in my assumption.

However, I'm still a little confused about the fuse ratings. IF there was an original 35 amp fuse then the wiring would have been big enough to support the current it might carry. This is where more (clearer) information is needed. Simply telling someone they're OK to stick a bunch of wires in a coke bottle without knowing the purpose or size or anything else that may be critical can be a big mistake. It's like suggesting to someone they test for lightning with their tongue. That CAN'T have good results.

In pictures posted he's shown both a 4 gang glass fuse holder and a 4 gang plastic fuse holder. I guess I got a little backwards on the way he was going, thinking he was going from 8 to 4. IF he's going from 4 to 8 (no picture of an 8 gang plastic fuse holder) then he's fine breaking the circuits out into individual circuits. As long as the potential current on any supply line does not exceed the wire gauge amperage rating.

Thought about editing my post but that might add to confusion. It's better to correct my comments here and go forward.

But if he's going to an 8 gang box then why does he want/need to splice wires together?

[edit] unless he's splicing the power source wires together. But then he could crimp two wires into the first crimp with the initial power wire and a jumper wire to the next fuse input terminal. Another double crimp and he could jump to the next. And the next and the next as the need may be.

Hi again all, thanks for explaining things. Going from a 4 fuse box to possibly an 8. Trouble is the 4 box has 4 connections for each fuse (2 each side) whereas the 8 has 2 (1 each side. Yes double crimp was what I was looking at. The fuse ratings half as the originals are Lucas glass fuses which are rated differently. Blade fuse ratings are half of the original glass fuses. I have a few different designs sketches to contemplate after working out what each wire is. Will let you know how I end up going about it. Cheers

 

It will be replacing the existing glass tube fuses to convert to blade type fuses. Lucas glass fuses are rated by the current which would blow them very quickly, whereas all other fuses everywhere, as far as I am aware, are rated by their continuous current carrying capability.

Not sure where you heard that but a fuse, be it glass cartridge or a blade type will open at its rated max current, the only question is at what point in time it will open. Each fuse is labeled with its rated current. How long a blade type automotive fuse takes to open is based on its rating. For example a 20 Amp 32 V Automotive Maxi (blade fuses come in different sizes) will have time/current characteristics just like a glass cartridge fuse. I can't see where we can arbitrarily say if I am replacing a glass cartridge type fuse with a blade type fuse that the blade fuse should be 1/2 the rated current of the glass type body fuse. If there is a credible link explaining this I want to read it.

Thanks
Ron