Fuse Distribution Block w/Relay Installation

[Ludedude]

What follows is a detailed write up on how I solved my 12v distribution needs with a system that accommodates both switched and constant power. I wanted to run a completely parallel and isolated 12v electrical distribution system to power accessories such as a ham radio(s), GPS, radar detector, power inverter, driving lights etc. I also wanted to keep the installation as clean looking as possible both to make things easy to work on and also to minimize the inevitable crust and clutter that will accumulate over the years of ownership I anticipate. I also wanted to avoid at all costs the rats nest of wires running all over the place that I've seen on so many occasions and I've been guilty of myself in the Jeep for example

Parts used:
Lightning Audio LFD2U dual AGU fuse block

Lightning Audio platinum plated 40 Amp AGU fuse, 4 pack

Littlefuse FHM0200Z Mini Add-a-circuit

Fuzeblocks.com FZ-1 fuse block w/relay



Miscellaneous: 1 gauge, 8 gauge and 12 gauge wire, heatshrink tubing, ring terminals, zipties, stainless steel hardware, uncountable numbers of scrapes, scratches and the liberal application of cursing as needed

Some pictures of the components I selected prior to installation. Please excuse the oh-so chic salmon colored background

















I settled on the FZ-1 block because it already has the 30 amp relay built in, it's incredibly compact and well laid out. It also allows for simply swapping a fuse over on the circuit board to switch a circuit and its attached accessories from constant on to on with ignition. No rewiring, no muss, no fuss. You can also simply change fuses if something blows and there are accommodations for spare fuses right on board. It's really a very slick unit. The functionality can of course be duplicated with liberal applications of time and fabbing but I was happy to find that someone had already done all that hard work for me All I needed to do was supply voltage directly from the battery and also a switched signal for the relay which I grabbed from the factory fuse block with the add-a-circuit tap.

Some installation pictures. They should be pretty self explanatory.



















One of the 40 amp fused outputs is used to run the internal FZ-1 block, the other is empty right now but will be used to run driving lights or anything else external that needs to draw power from the battery. At some point I may decide to relocate the AGU fuse block off of the fuse box cover. I was looking for a way to avoid drilling holes in metal since I'm always thinking of ways to easily remove mods should I decide to sell the vehicle. All I need to do is buy a new plastic cover and I'm right back to stock with no evidence. If I do relocate it to the inside of the fender or the top of the wheel well it will be trivial to make a longer 1 gauge cable to run from the battery. The 8 gauge cable that runs into the cabin has about 12 inches of extra slack in it that I can use if needed to open the cover of the fuse box or for relocation.

Part two of this post has the interior details.

[Ludedude]

Into the cabin we go. Some of these may be slightly crappy due to lighting and length of exposure challenges. That or I was getting tired.




(thanks for the easily accessible grommet Toyota!)




(glommed off the "acc" circuit but could also go to the cig lighter circuit to the right of it)







It took me a while to find a suitable location for the FZ-1 block. I looked around for a place under the driver's side dash but really didn't find anything I'd consider safe and accessible. There's already so much factory spaghetti under there that the potential of adding half a dozen or more sets of wires was just looking ridiculous. I started pulling panels off under the dash and finally found what seems to be a perfect spot behind the passenger side kick panel in front of the door. Plenty of room back there and it should be easy and clean to route the wires needed for as many accessories as I want to install there.



The FZ-1 block won't accommodate the 8 gauge wire I brought in from the engine compartment so I stepped down to 3 " of 12 gauge wire to make the connection to the terminals on the circuit board. The add-a-circuit comes in here too but it was already coming across from the other side with 12 gauge.



Here you can see how the fuses fit on the board and also how stupidly easy it is to choose constant or switched for any of the six available circuits.







I could swear that this white plastic bracket assembly was made with this part in mind. It practically snapped into place right there. I'll probably add some double-sided tape to keep it in place during anticipated Baja style action



More All done and awaiting the connection of the accessories. Hopefully someone finds this helpful if they're embarking on a similar mission.

I mounted the VHF/UHF ham antenna and ran the feedline under the driver's seat already. The next adventure will be installing the remote head and Icom 208-H tranceiver I acquired. I'll try to document that as well as I have a pretty neat location picked out for all of it.

[Teampez]

NICE write-up

[Net4n6]

"Here you can see how the fuses fit on the board and also how stupidly easy it is to choose constant or switched for any of the six available circuits."

How do you switch from constant power and back?

[Ludedude]

There are two columns of fuse holders; there are three contacts across with the middle contact being common. Moving a fuse from the left column to the right one changes the nature of the circuit from constant to switched.

In this image, the 10 amp fuse is configured as a switched circuit, the 5 amp as a constant on. to switch the configuration, just move the desired fuse over to the left or right.



I hope that's clearer. I have a huge-ass copy of the same picture available if you want but I chose to post the more reasonably sized ones in this writeup

[97kurt]

Sweet!! more stuff I need to buy

[Ludedude]

Originally Posted by 97kurt

Sweet!! more stuff I need to buy

Kurt.

Always glad to help out a friend

[Joel]

Nice setup! Love how easy it is to select constant or switched!

[Net4n6]

Originally Posted by Ludedude

There are two columns of fuse holders; there are three contacts across with the middle contact being common. Moving a fuse from the left column to the right one changes the nature of the circuit from constant to switched.

In this image, the 10 amp fuse is configured as a switched circuit, the 5 amp as a constant on. to switch the configuration, just move the desired fuse over to the left or right.



I hope that's clearer. I have a huge-ass copy of the same picture available if you want but I chose to post the more reasonably sized ones in this writeup

I see.... thank you. Great write up/

[Ludedude]

Originally Posted by Joel

Nice setup! Love how easy it is to select constant or switched!

Yeah that's really what sold me on this box rather than rolling my own.

[java230]

does one switch switch all the circuits?

[Ludedude]

No, there are a total of six circuits in the box. Each of them can be set to constant on or switched individually.

Here's a link to a much bigger picture of the board itself; you should be able to read the lettering on it easier and see how it's all constructed
http://www.lasvegashikes.com/gallery...s/P1010011.JPG
http://www.lasvegashikes.com/gallery...s/P1010052.JPG

There's a bare one and one with fuses in it to show how you'd configure it.

[java230]

so the one relay just shuts off the whole block then? i guess i should go to the wbsite and read up... seems interesting

[Ludedude]

The relay switches on or off, with the ignition, only those circuits you have selected to be switched like the 10 amp fuse in the second picture. Any that are set to constant, like the 5 amp fuse, are always powered up as long as the battery has juice

[java230]

Originally Posted by Ludedude

The relay switches on or off, with the ignition, only those circuits you have selected to be switched like the 10 amp fuse in the second picture. Any that are set to constant, like the 5 amp fuse, are always powered up as long as the battery has juice

ok thats what i thought the individual circuits arent switched.

[crazykz]

Originally Posted by java230

ok thats what i thought the individual circuits arent switched.

Hi,

JP told me about his thread so I was giving it a read and saw this post. I wanted to be sure that the unit was understood.

The individual circuits are switched but they can also be constant. It just depends on what position the fuse is put in for that circuit.

You can configure each of the 6 circuits to be switched or constant. There's an input to the relay on the fuzeblock that is fed from the ignition. The relay, when engaged, will route power to any circuit that has its fuse in the switched position. In other words when you turn the ignition on any circuit that has its fuse in the switched position will turn on. The circuits that have their fuse in the constant position will have power all the time.

Hopefully that clears it up.

Thanks,
Curt
--
http://www.fuzeblocks.com

[java230]

Originally Posted by crazykz

Hi,

JP told me about his thread so I was giving it a read and saw this post. I wanted to be sure that the unit was understood.

The individual circuits are switched but they can also be constant. It just depends on what position the fuse is put in for that circuit.

You can configure each of the 6 circuits to be switched or constant. There's an input to the relay on the fuzeblock that is fed from the ignition. The relay, when engaged, will route power to any circuit that has its fuse in the switched position. In other words when you turn the ignition on any circuit that has its fuse in the switched position will turn on. The circuits that have their fuse in the constant position will have power all the time.

Hopefully that clears it up.

Thanks,
Curt
--
http://www.fuzeblocks.com

yeah i understood that. looks like a cool product and great to see you guys are willing to join a forum to share info. i was hoping when i saw the title that each circuit was switched individually.

[crazykz]

Originally Posted by java230

yeah i understood that. looks like a cool product and great to see you guys are willing to join a forum to share info. i was hoping when i saw the title that each circuit was switched individually.

When you say switched individually you mean where each switched circuit would have it's own relay to turn each one on and off independent of the others?

That would be a cool option but that would require a lot of space on the board to jam in a lot of relays.

They do make some small sugar cube sized relays but they won't handle high current and they would still require more space on the board.

A way to hack that solution with a fuzeblock would be to run two wires off where the fuse would be for that circuit and have those feed the contacts of a relay. Then run a switched wire to that relay. It would only turn on when the vehicle was on and you pressed a button to activate that circuit. But that's obviously more hassle than just running a separate circuit.

Sorry for my confusion. That happens.

Curt

[java230]

^^^yeah thats waht i was hoping for. integrated relays and fuse block. i got lots o space....

[Ludedude]

Ah I see what you were getting at; it wasn't clear that you were wanting to have each individual circuit relay switched. Not in a 3" package that fits under the dash of a modern vehicle I think you're off to fab land for a switch panel and separate relay panel to do something like that. I don't know if you've looked around their site, but Painless is probably the only supplier that might have something like that in an off the shelf configuration.