DIY - Build and install a Bussmann RTMR Fuse/Relay Block

This is the best post I've ever seen on TW!

 

these parts are quite expensive, i'm pricing it out and i'm already over 100$ and haven't even gotten to the connectors yet that are 11.99 a piece on Amazon not including the components to build them, and i need probably about ten sets minimum.

looks like i found a 10 pack with all the bits for 18-20 AWG, all ill have to do is get the pins for 14-16 gauge and i should be good. also the kit comes with cable seals for 3 sizes of cable and includes the 2 sizes outlined here

$16 CNKF 10 Sets 2 Way Male and female 280 Metri-pack Connector Includes Terminals and Seals for FORD LINCOLN MERCURY 3U2Z-14S411-GEA /15300027

https://www.amazon.com/CNKF-Metri-p...dp/B01FALNXNE/ref=psdc_15727641_t1_B01FALOMOS.

haven't even gotten to pricing out multiple colors,sizes of cables yet....i may have to not get multiple colors and instead just label the cables really good




EDIT

OK i'm realizing now that those are 2 different connectors i spoke about above. so my question now is

why use Metri-pack connectors for the accessory connections? if weather-pack connectors are used for the switch harness? or vice versa...is it about the continuous amperage rating? i noticed the Metri-packs can handle more at 30 amps rather than the 20 for the weather pack.

the weather pack connectors are much cheaper in the fact that i can find them in a set already at the AWG i need for accessories and dont have to buy extra pins and seals. and just buy the metri pack pins for the RTMR.

 

Because the accessory harness doesn’t have matching 6-pin male and female connectors from Metripack, only Weatherpak.
Try customconnectorkits https://www.customconnectorkits.com/#
Also delcity https://m.delcity.net/
but it’s true, it adds up.

 

so is it acceptable to use the weather pack connectors for everything than at 20 amps continuous?

 

I was going to post it up here but i have some left over 18 ga wire from my build last year that I was thinking of selling. I might add some terminals if I find some.

 

You can use any connectors you want if they meet the requirements for your accessories. If you know your circuits will draw less current you can use less capable connectors. Part of the op’s design philosophy was to maximize each circuit up to those connectors for the sake of flexibility but it was a choice not a requirement. Using 20A connectors limits the circuits to 20A fuses just as using a smaller wire gauge would.

 

What are the downsides of using a blue sea 2508 https://www.bluesea.com/products/2510/Terminal_Block_30A_-_10_Circuit in ilo the metripack connector? I know not water resistant. Are there downfalls? It looks like this is how the Switch Pro works.

 

It doesn’t have relays. The bussman accommodates 5 sealed relays and 10 fuses in a waterproof enclosure with sealed wire terminals that has a smaller footprint. It’s not the only choice but if it fits the bill it’s a good choice. With the Blue Seas boxes you’ll need more space available to fit any separate relays. They both have benefits since the Blue Seas tops out at 100A total output vs the 80A of the Bussman and if you need more than 5 relays you’ll have to go outside the box anyway. But you might need to do that with either one if you need a 35A or more circuit. I needed two but have the room for the separate 40A fuses and sealed/skirted relays.

 

So this is a great write up and all but I'm suffering from paralysis by analysis right now. I plan to add some accessories to my truck in the near future.

• Always powered 12v power in the bed controlled by a locally mounted switch, (to power a fridge, led lights under the db cover, and accessories like charging a phone for running a small compressor)
• Always powered Under hood lighting
• A ignition switched circuit(s) for the aftermarket seat heaters
• auxillary lighting later on down the road

Is something like this appropriate for what i need, or is there a better option. Cost is not the issue, i just want to make sure i get the right thing the first time.

Although i would love to spend the money on new tools and build this myself, i would like to buy something that is already setup or close to it in order to save the time and put it towards other projects.

 

Don’t think of it as paralysis, just due diligence researching the possibilities before committing to a set of options.
Basically if you need to switch high power circuits on/off then you need relays but if you only need a single switch to heat up an auxiliary fuse box so those circuits become active then all you need is a breaker or battery switch.
The Bussman is one option and combines both fuses and relays but if you don’t need the relays you may be better off with one or more remote fuse panels. Simple led illumination is low enough power that it doesn’t require a relay so those aren’t needed for the engine bay and rear lighting unless you opt for high power spots for auxiliary driving lights. Likewise simple power outlets don’t need relays so you may choose to go with a few small remote fuse panels. This other thread shows a lot of the alternative choices people have gone with. https://www.tacomaworld.com/threads/show-off-your-aux-fuse-panels.308677/
I added one Bussman in the engine bay, another in the bed, and a small fuse only panel in the cab under the cup holder of the center console for seat heaters and switch power to minimize fuse taps on the stock panels. What types of accessories you want and where you want them will help you decide where it makes the most sense to put your power source(s).

 

@bagleboy knows his stuff and offers some compelling alternatives.

If you decide you need a bussmann and want it pre-assembled, get your name on the list here:
https://www.tacomaworld.com/threads/ongoing-small-batch-bussmann-rtmr-5relay-10fuse.400458/

 

From the OP

Take it as far as it needs to go.

 

Del City is having a 25% off sale. They carry most of the stuff you need for this project from Bussman to wire. Crap, sale seems to be on cable ties.

 

I have some left over parts from build. Let me know what you need and I’ll see what I can do.

 

Building a second unit for the bed and short a few tangless 280 #12/10’s since I used 2 5-pin relays to reverse the current on my rear cab/cap sliders in the one up front. The op build uses 20(10 for jumpers and 5 ea for relay and fuse output)and I used 22. The extra 2 provide a ground connection for the 87a pins.

 

I'd be interested in spare parts. I'm not ready to build mine yet so if anyone who is can benefit from your spares, please give preference to them.

 

Wow, just discovered this thread. I was wondering why more people didn't build a system like this! I am using GEP with micro relays as opposed to the bussman, but same concept. Good to see it's catching on. I will have to sit down and read through this thread to get up to speed.

Are you sure you need tangless? Like I said, I haven't read through this thread, so I'm not sure what all it is calling for, but tangless isn't that common. I know I have some lying around. Do they have to be 10/12 or would 12/14 be okay? I'll see what I have.

EDIT: The tangless ones I have are 12/14. If you need a few, DM me your address. I'll send you a few if those will work for you.

 

The Bussman uses female tangless to receive fuses and relays. The Metripack 280 connectors use m/f tanged terminals. I’ll send a message since 12/14 us what I’m using on the second unit, thanks.

 

I didn’t realize bussman used tangless. Good to know. Not many things use those that I’ve dealt with ( that’s why I have a crap load extra lying around all these years)

 

Decided to build this instead of buying one. Anyone have a current source for txl 10 awg by the foot or in a spool 100' or less?