Need some tips and help with fuse/relay boxes

Sturmovik

Bought an X
Hey everyone ! so I thought to ask the board for some tips and feedback on what cables should I get for future setup and where should I look to buy them ?

Amazon , Ebay or some other place... ?

I want to add Blue Sea Systems 12 port fuse


so I would love to see some ideas if anyone has done it before what cables did you guys used how did you end up and where installing ?

I was thinking that 4awg cable should be enough but not sure yet .

I plan to run lights ( light bar ,2 hood pods, maybe more over time, hopefully winch and compressor ) eventually ... lol

should I add main fuse ? on it or why since every 12 circuits will have its own fuse ? educate me )

I am also planning to get 6 port relay box and mount it somewhere too.. so all the relays from lights and other stuff would be there


If you have some other tips please feel free to add it will help alot .. this will be a long project but it worth it I feel like.



Thank you !
 

ffxcores

[fully disclosed]
Supporting Member
Location
Virginia
I’m following because I need to do the same thing and clean up the rat’s nest of wiring under my hood.
 

XterraRising

Bumpers Installed
Location
Utah
If you plan on using a relay box arrangement, plan on mounting it somewhere other than the engine bay. Damn thing is tight. If you don’t plan on using your factory jack and associated tire tools, under the seat could work for a relay box.

Two major issues you’ll run into is switching, your battery home run, and lights to the actual components. This can be as simple or as complicated as you dare make it.

Essentially, understand that a relay is simply a switch unto itself. You are using a very small current to switch a large current. The distance your wires have to travel to your accessories, plus the current draw of said accessories is going to play a huge part in wire gauge size. The longer the run, and the higher the current, the bigger your wires have to be. The good news is you can find wire size charts anywhere on the internet.

I would recommend that when it comes to wire sizing, you follow an 80% rule. Upsize your wires so that your nominal loads are only 80% of what the current rating of the wire is. This will help prevent heat and give some overcurrent protection in addition to an appropriate sized fuse.

On the later Xterra’s the passenger side, under the cab, is pretty wide open for your wire runs under the body. Be mindful of the exhaust though.

If you don’t plan on mounting anything else under the passenger seat, that is a good place for a relay box too.

On my Xterra post “XterraRising,” I also have some part numbers for some connectors specific to Nissan and the like. Might help for those off chance scenarios where you want to wire in a factory type relay socket.
 

reaver

Lockers Installed
Supporting Member
Location
Caldwell, ID
What @XterraRising said. In my 2003, I ran 4awg positive and negative wires through the firewall to my fuse block, which is mounted in my drawer system. This is plenty big enough to be able to push 100A safely.

I run a 100A fuse block, with a separate relay box with its own fuses for my lights. I currently only have two lights hooked to the relay box.

On the positive wire, before passing through the firewall, is an 80A breaker. It serves two purposes. First is obviously to trip if the draw is more than 80A. This way, I can never hit the full capacity of the fuse block, and cause it to overheat and catch fire. The second is that it acts as a disconnect for when the truck is parked for a long time (it's not my daily).

To give you an idea of how I laid out my electrical, here's a diagram I made showing the system:

Xterra-Electrical-Diagram.png


As you can see, there's ALOT of Relays. I know it looks complicated, but it's really pretty simple if you tackle one thing at a time. You just need to figure out what current draw your devices/accessories will be using, and use the correct size wire for the length of the run. In my case, I did everything with 12awg wire. The highest draw item I have is my inverter, which is only 300w, and is only about 24in from the fuse block. This means it will draw a max A of 25A (300w / 12v =25A). I might even bump that up to 10awg wires just to provide a buffer.

I highly recommend planning everything out as best you can before starting any work. It makes life way easier not going in blind.
 

Sturmovik

Bought an X
Thank you so much guys this is alot of good info !

I still have few questions...
1st where would you recommend to buy those wires ? 4awg . 12awg do you buy them as a single cable or 12/2awg ?

2nd so you would recommend mount the Fuse box and relay box somewhere inside ( under dash, under seat ) no under hood ?

Here are some things that I plan to install , use over time.
light bar ( already installed and tested pulling only under 10A )
2 Pod lights on hood.

Down the road
Winch ( but that will be connected directly to battery bypassing fuse box if Im not mistaking )
Air Compressor
Inverter ... ( not too big just enough to power up and charger batters for cameras and drone )
Air horns ( big maybe , not sure I will go that way but maybe )
and perhaps some more lights and small things here and there..
can't think of anything else...

P.S very nice diagram ! very easy to understand what goes where ! wow !


P.S.S the headlight circuit on the diagram did you just went with add a fuse to make the switches light up only when the car is running
?

P.S.S.S ... also could you show where in firewall you send your wires ? ) how did you seal it. ?
 
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XterraRising

Bumpers Installed
Location
Utah
I just buy my cables and wires from Amazon because I can get them cheaper than the parts houses here. get stranded cables and wire. No solid wire for vehicles. Vibration and solid cables don’t mix.

I had a hard time finding a suitable location under the hood for even a small fuse block. So if you can find a location somewhere else, that’d be ideal. This way, you can run just one large positive and negative to the battery. Those go to common buses in the fuse/relay box and you can pull your power and grounds there. I would install your main fuses/breaker close to the battery. I have a maxi fuse installed on top of the IPDM box for my power inverter. That way, if something gets broken down the line, the fuse will blow and protect my truck from burning to the ground. I’m a big believer in keeping fuses as close to the power source, or switching source as possible and practical.

On the headlight circuit, guys oftentimes pull their signal wire off the headlight so their lighting accessories only come on when the lights are on. In the case of my auxiliary fog lights, I pulled a signal wire from my tail lights to my latching relay. That way I can only turn on the lights when the tail lights are on. The added benefit for me is that when my lights turn off, the latching relay loses signal, and the fog lights turn off. They won’t turn back on until my tail lights are back on AND I push my button again. Keeps the battery from dying if I forget.
 

Sturmovik

Bought an X
For the main fuse I was thinking ( suggested by member ) to use this .. closer to the battery ..


yes I will need to set up something too so it only lights up when truck is running or lights are on... righ now.. I wired up light bar and wire harness and the on/off switch is on all the time.. ( i left it like that as temp ) to test will it kill batt in a week.. when truck is parked..

I trying to find some good quality and price cables now on amazon for 4 and 12awg
 

XterraRising

Bumpers Installed
Location
Utah
That’s a good fuse, but I’d worry about availability in a pinch. Here’s another option.

MEGA/AMG Fuse, 298 Series, Bolt Down - Automotive/Marine (Fuse Holder) https://www.amazon.com/dp/B07THLWWV...abc_HGM5929TF1MJAW6SK3R8?_encoding=UTF8&psc=1

Here is the Mega fuse itself.

Bussmann AMG-175 AMG High-Current... https://www.amazon.com/dp/B000PSR8V6?ref=ppx_pop_mob_ap_share

Now obviously, a 175 amp fuses is a little much for lighting, but it is for my inverter. You can get these fuses at almost every parts house and fuse shop. Pro tip: get Bussman fuses. Don’t dick around with anything else.
 

Sturmovik

Bought an X
that s a good tip..indeed as I understand now.. the other fuse might look cool but it it blows then yah I need to get same one
as in the one you showed its more practical and if it blows all i need to replace the fuse itlsef not the full thing... makes sense !
 

reaver

Lockers Installed
Supporting Member
Location
Caldwell, ID
Thank you so much guys this is alot of good info !

I still have few questions...
1st where would you recommend to buy those wires ? 4awg . 12awg do you buy them as a single cable or 12/2awg ?

2nd so you would recommend mount the Fuse box and relay box somewhere inside ( under dash, under seat ) no under hood ?

Here are some things that I plan to install , use over time.
light bar ( already installed and tested pulling only under 10A )
2 Pod lights on hood.

Down the road
Winch ( but that will be connected directly to battery bypassing fuse box if Im not mistaking )
Air Compressor
Inverter ... ( not too big just enough to power up and charger batters for cameras and drone )
Air horns ( big maybe , not sure I will go that way but maybe )
and perhaps some more lights and small things here and there..
can't think of anything else...

P.S very nice diagram ! very easy to understand what goes where ! wow !


P.S.S the headlight circuit on the diagram did you just went with add a fuse to make the switches light up only when the car is running
?

P.S.S.S ... also could you show where in firewall you send your wires ? ) how did you seal it. ?
I order all my wire, fuses, Relays, relay box, fuse blocks, switches, and EVERYTHING else from Amazon. Pretty much everything but the fuses, and switches are made by a company called online led. Iflve not had an issue with them, and they appear to be of good quality.

If you can get a sealed fuse box and Relays, I don't see any reason why they wouldn't work under the hood (fitting them is a different story).

We tapped into the dash light circuit to turn the switch lights on, and did not use an add a fuse.

We just found a grommet on mine that had enough room to feed two 4 gauge wires through. On my 03,this was down by the passenger footwell wall.
 

RM975

First Fill-Up (of many)
Location
Templeton, Ca
That’s a good fuse, but I’d worry about availability in a pinch. Here’s another option.
You can get these fuses at almost every parts house and fuse shop. Pro tip: get Bussman fuses. Don’t dick around with anything else.

Reinforcing this. Go with a large fuse style that is readily available.
 

Sturmovik

Bought an X
I need to find that company and see what I can buy from them.. on my 1st search it didn't bring up any results but maybe I mistyped it..

along with Blue Sea Sytem fuse box I also bought this box to put it in to keep it clean and sealed .

so you basically used t-tap type of connector to tap into it am I correct ?

sorry for so many questions :)
 

RM975

First Fill-Up (of many)
Location
Templeton, Ca
I need to find that company and see what I can buy from them.. on my 1st search it didn't bring up any results but maybe I mistyped it..

along with Blue Sea Sytem fuse box I also bought this box to put it in to keep it clean and sealed .

so you basically used t-tap type of connector to tap into it am I correct ?

sorry for so many questions :)
Busmann? Common brand in parts stores. Also available on Amazon.
 

reaver

Lockers Installed
Supporting Member
Location
Caldwell, ID
I need to find that company and see what I can buy from them.. on my 1st search it didn't bring up any results but maybe I mistyped it..

along with Blue Sea Sytem fuse box I also bought this box to put it in to keep it clean and sealed .

so you basically used t-tap type of connector to tap into it am I correct ?

sorry for so many questions :)
As is, that'll seal just fine. The problem is, once you start drilling holes, you compromise the seal on the box. You can use cable glands to help keep water out, but they're not 100% waterproof.

Depending on how many wires you'll need to drill, that's gonna be a lot of holes.
 

RM975

First Fill-Up (of many)
Location
Templeton, Ca
Put the BSS box in the cab. There is a spot just outboard of the brake pedal. Also there is a large rubber firewall plug to run wires through.
 

Sturmovik

Bought an X
for 2 main cables coming in.. Positive and Negative I am planning to use those connectors to keep it seal


for the rest of the wires.. Im still working on it LOL but thinking to find a rubber gaskets or something that i can drill hole into the box and push my wire thro it or something ..

something like this.. perhaps different kit.. to fit wires better

 

RM975

First Fill-Up (of many)
Location
Templeton, Ca
One option is a rubber grommet backed up by RTV. When I popped out the satt antenna in the roof to run my radio coax through that hole, that is what I did. No leaks since 2006.
 

XterraRising

Bumpers Installed
Location
Utah
Cable glands FTW. Come in different sizes. They are waterproof, protect from metal edges, and provide strain relief.

Cable Gland - Lokman 20 Pack PG11 Plastic Waterproof Adjustable 5-10mm Cable Glands Joints With Rubber Gaskets, Black (PG11) https://www.amazon.com/dp/B06Y5F6G6...abc_14YDKHWDQYCW4B34SYVB?_encoding=UTF8&psc=1

They are a bit bigger than a simple o-ring, but if you swing it, they are worth it. Here’s some big ones for the 2/0 cable I routed under my passenger seat for my power inverter.

iaDEn2i.jpg
 

Sturmovik

Bought an X
Cable glands FTW. Come in different sizes. They are waterproof, protect from metal edges, and provide strain relief.

Cable Gland - Lokman 20 Pack PG11 Plastic Waterproof Adjustable 5-10mm Cable Glands Joints With Rubber Gaskets, Black (PG11) https://www.amazon.com/dp/B06Y5F6G6...abc_14YDKHWDQYCW4B34SYVB?_encoding=UTF8&psc=1

They are a bit bigger than a simple o-ring, but if you swing it, they are worth it. Here’s some big ones for the 2/0 cable I routed under my passenger seat for my power inverter.

iaDEn2i.jpg
yeah I am defiantly want to get those like I said for main cables.. but if they make them in smaller size.. for single cables that I will be using lets say for lights and other stuff I will defiantly rather use them as when you tight them they actually keep cable in place
I like using them.. ( use them at work ) but they are ether 3/4 or 1/2 the one we use
 
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