12-Circuit Auxiliary Fuse block install

**ebi718** · 07-04-2016 09:15 PM

For a while, with the growing collection of toys/accessories in my C6 Avant, I have been looking to expand the power sources available. I finally installed a secondary fuse block + circuit breaker this past weekend. So far, it has been working as designed, with room for expansion if necessary.

Below is a very rough outline of the set up.

PS: The above diagram shows the wiring for ONE relay - the setup will be same for the other 3 or more relays.

This is the set up as it is today, on the storage 'cubby' (in the trunk area) that's normally covered by the folding board.

Below is a listing of parts I got:
1. Blue Sea 12-circuit (split) Fuse block @ $40
2. 15' of 4 AWG Premium Extra Flexible (Red and Black) @ $34
3. Bussman 100amp Type III circuit breaker at $20
4. 12x12x1/8inch ABS plastic @ $10
5. Bosch-style 5-pack 30/40amp automotive relay @ $14
6. 45' of 12/14 AWG automotive wire
7. 2 Pcs 8 position distribution block (for use with relays) @ $5
8. Ring terminals, crimp connectors
9. Standard size blade-type fuses (different amperages depending on your need)
10. Techflex 3/8" 25 ft. Black Expandable Sleeving @ $17
11. Split wire loom, zip ties

You could also source these from eBay.

Disclaimer: As with all electrical work on your vehicle, take note to disconnect the negative (-) battery cable for obvious reasons before proceeding to avoid risk of electric shock, fire or injury. Also, be aware that the photos shown here may not necessarily match your vehicle; if you intend to replicate this, do your due diligence and proceed at your own risk.

Summary: The goal for this project was to provide extra fuseable sources of power (mixture of both 'hot always' and switchable) to meet current and future requirements. With the Blue Sea fuse block (P/N 5032), the 12 circuits are separated into 2 primary busses - A and B. Of the 12 circuits, I chose to put 4 on separate relays that would be triggered by a switched circuit from the OEM fuse box (using an add-a-circuit fused for 3amps). This way, 8 will be 'hot always'.

Power is routed to 100 amp breaker and then to the fuse block using 4AWG wire. Same wire gauge is also used to provide ground (-) to the chassis.
The breaker serves as :
- a mains on/off switch,
- a 100A Fuse, and
provides circuit protection if current draw exceeds 100 amps (which is the rating for the Blue Sea fuse block).

For the 4 switched/fused circuits, power is routed to 4 relays (via PIN #30, red wire). The yellow wire (coming from a switched circuit in the OEM fuse box) is used to energize the coils (on all 4 relays) - the wires are daisy-chained using the positions 5 thru 8 of distribution box shown below. Once the ACC switch is turned on, the coils are energized and PINs #87 (blue wire) on all 4 relays are closed, thus making them 'hot'.

Picture #3 below shows the initial wiring on my 'test bench'. Most of the components are mounted on the ABS plastic board. (This board is bound to the rubber floor in the trunk with rivets). Ps: Some others have been successful with a Lexan (instead of ABS sheets for mounting the fuse block).

As picture #4 shows below, I have connected my TV Tuner and Android Box to 2 of the fused/switched circuits (7.5amps and 3amps respectively). Bottom left is the DROK 5V 3amp buck converter used to run the android box.

In terms of performance, I noticed that the interference/noise noticeable in the TV tuner/Android box audio/video (from the alternator) is gone! I still need to do some clean up (zip ties, heat shrink, etc). Will provide updates as they become available.

I hope this helps. Please feel free to ask any questions and I'll try to address them as best as I can.

Cheers