Aux Fuse Block Wiring Questions (1 Viewer)

[lugueto]

Hello guys,

I changed out the battery terminals on my truck and I realized that my wiring is a mess. Stock wiring is pristine, but the additional circuits I added are cluttering the battery terminals and engine bay.

So I bought a Blue Sea fuse block to clean out my wiring and a couple of questions rose:

1) Can these things be safely installed in the engine compartment? The lid does not seal the fuses.

2) I bought a unit with a dedicated negative bus without knowing. is it better to use separate grounds or am I forced (or perhaps better) to route grounds back to the fuse block?

3) What gauge wire do you run between the battery and the fuse block? I plan to run five separate circuits including a pair of 130w halogens.

4) I want to clean up the way I passed the wiring through the main firewall grommet. Any ideas on the best way of doing this?? I was thinking about poking a hole into it, stick a half-inch piece of rubber tubing and after I get the wiring through and wrap it in electrical tape.

I think my VHF radio is the only additional electronic equipment that will remain connected directly to the battery. My two front aux light circuits, back-up light circuit, power inverter and additional 12v socket will be run through the fuse block.

Anybody care to help??

Thank you in advance,

Luis

 

[george_tlc]

The blue sea fuse block works great and has no issues under the hood. Had one on my patrol for a few years and no issues with dirt/dust/mud splashing etc. Consider that the factory fuse blocks are rarely 'water tight' - certainly the 80 series ones under the hood aren't. We're only dealing with 12V...

Search for current and wire gauge - plenty of online resources to help size your cables appropriately for the expected current load (or at least to the point the fuse blows). If you run a distance between the battery and the blue sea fuse block, then it wouldn't be a bad idea to protect that cable with a high current fuse (maxifuse/megafuse/ann fuse etc) sized to protect that cable.

No need to use the ground connection on the fuse block - remember a lot of blue sea applications are boats that are mostly fibreglass etc...

Don't use insulation tape if you can - at the very least use self vulcanising silicone tape - much better seal and doesn't become a sticky unraveled mess a few years late. Liquid tape is also handy for sealing things up, especially bulkheads.

cheers,
george.

 

[Tapage]

as George said .. no problem in your engine bay ... here is the one I have in my 80 was unfinished at pic time but you got the idea .. few of my grounds are running up to the bluesea and few others are where relay is ..

 

[lugueto]

Awesome.

I wasn't worried about it being water tight, as I know the OEM ones arent, but these ones have openings everywhere and I didnt know how that would affect. Great to hear they can be safely installed in the engine bay.

I do believe I have a little self vulcanizing tape around. It would only be used for the grommet, though. But I agree, electric tape ages very poorly..

Do you remember what gauge wire you used for the positive feed in your fuse block Tapage?

My new fuse block will be installed right next to the factory one. I havent decided on adding a circuit breaker to the positive feed wire, will that be necessary?

I figured I wouldnt need the negative bus, I'll just keep my grounds where they are, simpler.

Also, how are you passing your wiring into the cab??? Any pictures of a clean way to do it? Mine's horrible at the moment..

 

[Tapage]

Do you remember what gauge wire you used for the positive feed in your fuse block Tapage?

#4 IIRC .. and ground was #6 again IIRC

Also, how are you passing your wiring into the cab??? Any pictures of a clean way to do it? Mine's horrible at the moment..

I drill a hole trough my FW and use a grommet ..

 

[ntsqd]

FWIW the ABYC spec for an unprotected wire run is 7 inches. If the wire from the battery to the fuse panel is less than 7" long then by their rules it doesn't need a fuse or a breaker. Obviously you're not wiring a boat, but I find their rules to be reasonably applicable and to address a lot of the same questions that arise in these vehicles.

The fuse isn't to protect the device at the other end. It is protection for the wire between the panel and the device.

 

[lugueto]

Ok, and what spec breaker/fuse should I use??

This is beyond my knowledge as its my first big wiring project...

 

[george_tlc]

Like my first post in this thread stated. You need to choose the fuse/breaker that is between the battery and the fuse block to PROTECT that cable. The fuse block fuses will protect the cables and devices AFTER the fuse block.

Think of the fuse/breaker at the battery as the equivalent of the Toyota fusible links on the main battery.

Your first step is to determine all the loads on your fuse block (present and future). Add all those up. Pick a main battery/fuse block cable to handle that current load (+ some margin). GOOGLE for "current wire gauge" to find some sites that document wire gauge versus current carrying capability. Choose your cable. Chose a fuse/breaker that will BLOW/TRIP below the maximum current rating of your cable.

Also, don't exceed the maximum rating of the Blue Sea fuse block.

cheers,
george.

 

[lugueto]

Ok, so this is getting bigger and bigger lol.

So i'll be using #4 cable from the battery with a 80A circuit breaker, which should prove sufficient If I include the inverter. I will be running my 130W halogens, front facing Rigid Dually's, Rear facing rigid dually's, an always-on 12V socket and maybe a 500W power inverter. My VHF will still be connected directly to the battery as per manufacturer recommendations. The only circuit that concerns me is the inverter, which should be over the 30A rating for the individual circuits according to Blue Sea, so I might not install that.

Im also tinkering with the Idea of buying a firewall wiring boot and pass all my additional wiring into the cab, that way the stock boots are left alone (best). Although I'm never particularly fond of drilling my vehicle anywhere.... The sound it makes is only bearable when installing a snorkel lol

 

[lugueto]

I bought a firewall boot to make the install perfectly clean. Now i'm wondering:

What sort of drillbit would you use to drill a 1.25in hole in the firewall?? A stepped bit? I have no clue..

 

[Tapage]

A stepped bit? I have no clue..

or ..

 

[FJ60Seth]

Pic and link of your firewall boot please.

 

[lugueto]

http://www.amazon.com/dp/B004K2285E/?tag=ihco-20

Cheap, too..