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Rockford Fosgate RFK4D

4-gauge dual amplifier complete wiring kit

Item # 575RFK4D

Your amp needs big power wires in order to deliver top performance to your sound system.

Your amp needs big power wires in order to deliver top performance to your sound system.

In stock

About the Rockford Fosgate RFK4D

Your amp needs big power wires in order to deliver top performance to your sound system. Rockford Fosgate's RFK4D amplifier wiring kit supplies everything you'll need to send power and signal to two amps and your speakers. It's designed for amplifiers with fuse ratings totaling up to 100 amperes.

This kit includes patch cables and speaker wire for installing two 2-channel or mono amps — you'll need to add cables and speaker wire if you're installing a multi-channel amp along with a second amp.

Your amp needs big power wires in order to deliver top performance to your sound system. Rockford Fosgate's RFK4D amplifier wiring kit supplies everything you'll need to send power and signal to two amps and your speakers. It's designed for amplifiers with fuse ratings totaling up to 100 amperes.

The kit includes two distribution blocks, 4-gauge power and ground cables, 8-gauge power and ground cables, speaker wire, two patch cables, a fuse holder, a 100-amp fuse, and more. Rockford Fosgate makes these cables from 100% pure crystal-oxygen free copper wire so you can count on maximum signal transfer.


Product highlights:

  • dual amplifier wiring kit
  • cables meet or exceed the American Wire Gauge specifications and requirements
  • 17 feet of 4-gauge power cable
  • 6 feet of 8-gauge power cable
  • 3 feet of 4-gauge ground cable
  • 6 feet of 8-gauge ground cable
  • 20 feet of 18-gauge turn-on lead wire
  • two 16-foot twisted pair RCA patch cables
  • 30 feet of 16-gauge speaker wire
  • MAXI fuse holder and 100-amp fuse
  • two 4-gauge to 8-gauge distribution blocks
  • assortment of wire termination hardware and cable ties
  • warranty: 1 year
  • Our 60-day money-back guarantee
  • MFR # RFK4D

What's in the box:

  • 17' Power cable (4-gauge) in a red translucent jacket (has an in-line MAXI fuse holder and a ring terminal on the battery end)
  • 3' Ground cable (4-gauge) in a gray translucent jacket (with a ring terminal on one end)
  • 6' Power cable (8-gauge) in a red translucent jacket
  • 6' Ground cable (8-gauge) in a gray translucent jacket
  • 2 Distribution blocks (One 4-gauge in/Three 8-gauge out)
  • Two 16' twisted pair RCA patch cords
  • 30' Length of 16-AWG speaker wire
  • 20' Length of turn-on lead in a blue jacket
  • Ten 4" wire ties
  • Plastic bag containing the following:
  • Crimp-on ring terminal for 4-gauge wire
  • Large black rubber boot
  • 100A MAXI fuse
  • Plastic 4 gauge-sized grommet
  • 2 Red plastic butt connectors
  • 5 Crimp-on female 0.25" quick slide connectors
  • 5 Crimp-on spade connectors
  • 3 Red rubber boots
  • 2 Black rubber boots
  • Decal with model and serial numbers

Customer reviews

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Rockford Fosgate RFK4D reviews

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More details on the Rockford Fosgate RFK4D

Mark G.
The Rockford Fosgate RFK4D replaces these items:

Product Research


General Overview: This is a dual amplifier wiring kit that includes 4-gauge and 8-gauge power and ground cables, power distribution blocks, turn-on leads, two pairs of stereo RCA cables, a 30' length of 16-AWG speaker wire and other accessories required to install two amplifiers.

High Strand Power/Ground Cable: The power and ground cable are 100% Pure Crystal-Oxygen Free Copper (PC-OFC) and meet or exceed AWG (American Wire Gauge) requirements. For example, the included 4-gauge power and ground wires each have 1,862 copper strands, compared to the 735 copper strands which meets the standard.

In-line Fuse Holder: The included in-line fuse holder attached to the power cable comes with a 100-amp MAXI-type fuse.

Power Distribution: The kit includes two unfused power distribution blocks. Each block has a single input and three outputs. There are insert sleeves that allow you to use multiple sizes of wire: a 1/0 gauge-to-4 gauge sleeve for the input, and three 4 gauge-to-8 gauge sleeves for the output.

Patch Cables: There are two 16' RCA patch cables included, each with twisted pair design for noise rejection, and a split center pin that helps secure the connections at both ends.

Speaker Wire: The amplifier kit comes supplied with high strand 16-AWG speaker wire for increased sound transfer.

Accessories: The kit includes the following accessories needed for amplifier installation:

  • Ring terminal for 4-gauge wire and rubber boot
  • Spade terminals for 16-gauge speaker wires with red and black rubber boots
  • Female quick slides for 16-gauge speaker wires
  • Butt connectors for splicing together wires
  • Grommet for routing 4-gauge power wire through the firewall
  • Wire ties for securing wires to the vehicle

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Customer Q&A

Crutchfield asked: Why did you buy this?
I am almost done with my sound system build and Crutchfield has EVERYTHING I NEED TO COMPLETE MY PROJECT ???? thanks Crutchfield [ Neto jr   May 04, 2020 ]
I need it to make the system work . [ Gabriel  Feb 28, 2020 ]
Looks like a complete kit and rockford fosgate always good brand and decent price [ giovanny  Nov 10, 2019 ]
Always choose only the best [ Patrick  Sep 13, 2019 ]
Good brand, correct watts and channels for my speakers, and decently priced compared to most name brands [ William  Apr 13, 2019 ]
Great product! [ Stanley M.  Mar 24, 2019 ]
This one came with two distribution blocks (power and ground) as opposed to the Crutchfield kit that only came with one block. [ B  Mar 14, 2019 ]
Crutchfield hands down has the best customer service in retail business. Other businesses could learn a few things from these fine people. [ Arturo  Feb 14, 2019 ]
Needed to pump up my new speakers, and the reviews were good. [ John  Jan 24, 2019 ]
Cause I love rocksford and I'm installing two amps [ Stan  Jan 17, 2019 ]
Fosgate sale/ needed since I am now adding a second amp. [ Richard  Dec 31, 2018 ]
Rockford Fosgate amp wiring kits are always of good quality. Positive and negative splitters are included in the kit and are easy to mount under a seat or on a amp rack. [ Charles M  Dec 30, 2018 ]
Recommended by tech [ Martin  Jun 22, 2018 ]
it looked like a good kit to use with my new system [ Nicholas  Jun 07, 2018 ]
one of the staff advise me on this product [ LAURISTON  May 03, 2018 ]
I liked [ Chris  Dec 22, 2017 ]
Helps install [ Chris  Sep 07, 2017 ]
needed to hook up multiple amps. [ MICHAEL  Aug 25, 2017 ]
I chose the RFK4D because Rockford Fosgate is a well-known brand with a solid track record. This wiring kit appears to have quality components and comes with almost everything needed to wire two amplifiers (could use a third set of RCA cables. It only comes with two, but you need one set for the Sub channel, one for the front speakers and one for the rear speakers). The price is also reasonable, and this kit has great reviews from other buyers. [ Oliver  Jul 25, 2017 ]
I needed an amp wiring kit that would allow me to hook up two amps. Sub and components amp. Reliable power and products. [ Charles  Jul 11, 2017 ]
Added year warranty to amps [ Donna  May 31, 2017 ]
Almost Complete [ Philip  Apr 20, 2017 ]
Required to install the amps in the Taco. [ THEODORE  Mar 18, 2017 ]
Quality of brand [ josh  Mar 01, 2017 ]
Very good all in one amp wiring kit to power up my system. Was looking for good quality for a good price. [ Joseph L.  Jan 21, 2017 ]
To Install 2 amp, 1 four channel and 1 mono for a woofer. [ Juan C.  Jan 16, 2017 ]
All in one kit for multiple amps [ Michael  Oct 01, 2016 ]
Good brand [ Charles  Sep 24, 2016 ]
It has everything that i need to hook up the two amps i just bought from you guys. [ trinidad  Sep 11, 2016 ]
Used this before, great product. [ Lyvierre  Sep 05, 2016 ]
Friend [ Jonathan  Jun 20, 2016 ]
Great product and great quality. Included everything I needed for a 5-channel amp setup. [ jorey  Apr 16, 2016 ]
Pure oxygen free copper..I'm adding a third amp as well, so the distribution blocks will work out perfectly. This kit also includes two more feet of 8 awg than the Kicker kit, which I will need. I like the fuse block better on the Kicker kit however. [ travis  Mar 15, 2016 ]
Quality wires are needed for quality install in regards to power and signal [ Matt  Mar 11, 2016 ]
Installing system and need solid wiring foundation. Looks like complete kit and Rockford Fosgate is high quality. [ Patrick  Jan 10, 2016 ]
To hook up two amplifiers [ Sergio  Dec 21, 2015 ]

7 questions already asked

Does this kit provide a capacitor and all the fuses I need? I read multiple places that I need a fuse on both sides of the distribution block? Also, do I need to buy a harness separately? Is there ANYTHING I need to buy besides the kit to connect the signal and power to the amps and the to the speakers? Sorry, I've never done this before.
[ Ben  May 20, 2020 ]
2 answers
It does not come with a capacitor. The kit is for the installation of two amps. I used it to power one amp for 2 twelve inch subs and the other for 6 speakers. It's not to hard to install.
[ raymond  May 20, 2020 ]
This kit does not provide a capacitor. If your setup will require one, purchase it separately. This kit comes with 1 large fuse that fits in an inline holder at the battery or capacitor end. It does not have other fuses for in between your components. Your amps should have adequate protection on board, but you could always put another fuse/distribution block or inline holder for each amp. I did not when I installed this kit. Other than that, this kit is full of everything else you need.
[ MICHAEL  May 20, 2020 ]
Does this kit provide a capacitor and all the fuses I need? I read multiple places that I need a fuse on both sides of the distribution block? Also, do I need to buy a harness separately? Is there ANYTHING I need to buy besides the kit to connect the signal and power to the amps and the to the speakers? Sorry, I've never done this before.
[ Ben  May 20, 2020 ]
3 answers
No a Capacitor is sold separately. You get the main fuse from the battery. I've never used a fuse on both sides of the distribution block usually the main from the battery and the amp should have its own fuse. No separate harness should be needed for the capacitor maybe extra fittings if they don't come with the capacitor.
[ mamdouh  May 20, 2020 ]
There is one fuse and no capacitor in this kit
[ CRAIG  May 20, 2020 ]
The kit is complete with a 100 amp fuse that goes right after the battery connection. I did not put any additional fuses after the distribution block. Works fine
[ JOE  May 20, 2020 ]
This kit doesn't look sufficient for multiple amps, as there seems to be only 1 set of power and ground cables for the battery and 1 amp from the distribution block, or am I missing something?
[ BRADLEE  Mar 07, 2020 ]
5 answers
4 ga from battery to the distribution block then 8-ga from distribution block split to two amps. Hope that helps!
[ Kent  Apr 02, 2020 ]
The provided 8 ga wire is intended to be cut to split it between the 2 amps.
[ Nate  Apr 02, 2020 ]
This kit is capable of running 2 amplifiers. I used this kit for 2 amps on my harley
[ Joshua  Apr 02, 2020 ]
It is, that's what I ordered. D block had three outputs, you'll have one empty
[ Jose De La  Apr 02, 2020 ]
There are 2 distribution blocks that will supply power to 2 amps.
[ JOE  Apr 02, 2020 ]
I'm looking to add 2 amps but firstly only one for the sub, one 500w mono at 2 ohm for my 2 ohm sub and a second 100w/ 4 4 ohm for the speakers. would this be all I need in terms of power and needed wires ? Keeping in mind that the 2nd amp recommends 4 gauge alone itself.
[ FireSpider  Nov 23, 2019 ]
1 answer
We would have to look at your amp's fuses to make sure, but I am fairly confident this kit would work to give power to them. It doesn't come with speaker wire big enough for a sub and I recommend looking at 12 gauge wire for that. You may also need a second RCA audio cable. We have advisors that you can contact by calling 1-800-324-9695 to discuss your amps, radio, etc... to get a personal recommendation on all the wiring you will need.
[ Paul  Dec 16, 2019 ]  Staff
Hi i have 2 amps and i wanted to connect them but i need a little help. My subwoofer amp is 750w rms. My speakers amp is 300w rms. I wanted to buy a 4 awg dual amp kit RFK4D. This amp kit 4awg can handlet about 1000w So now does this 4awg dual amp kit it is good for my installation or should i go for 1/0 Awg dual amp kit Because i think when 4awg cable goes to distribution block it shares the power for both amps, 4awg goes to 8 awg and i think 8awg its now enough for my 750w rms sub amp, or should i buy 1/0 gauge dual amp kit that is enough when it goes to distribution block because 4 awg can handlet 1000w rms which is bigger than what i am asking for? Thank you for your time.
[ Pellumb  Jul 08, 2018 ]
3 answers
For the power you specified, 4 is enough, been running a similar setup for many years with no issues.
[ Jose De La  Apr 02, 2020 ]
I'll go with the 1 awg can't got wrong with that coming of battery n u branching of with a smaller size
[ Charles  Jul 14, 2018 ]
Not necessarily. I was running a 'dual amp kit' from Rockford Fosgate, a 4 gauge kit. I had a 600/4 amp for my mids, running 125w @ 4ohms per corner. I also had a 2400.1d amp running 1200w at 2ohms. I recommend the dual 4gauge amp kit from your information given. This should provide plenty of clean power, provided your amps can run stable ohms at what your speakers are rated for. And for the sub(s) depending if you run them parallel or in series will depend on the final impedance in ohms.
[ Drew  Jul 13, 2018 ]
why only one fuse for two amps?
[ Steve  Nov 28, 2016 ]
3 answers
Each amp has it's own fuse, to protect the amps. The fuse on the main power line which is connected to the battery, protects the vehicle.
[ Matthew  Nov 29, 2016 ]
You can run two fuses!
[ Lee  Nov 29, 2016 ]
The main fuse is supposed to be near the battery. The power splitter for the two amps may be in the car trunk. If your amps don't have their own fuses and you want them, you may be able to install some. It's a nice kit, and Crutchfield tech support will help you with the install.
[ Marlin  Nov 29, 2016 ]
I was wondering if this kit includes everything to install both a 2 channel and 4 channel amp at the same time?
[ Drew  Feb 19, 2014 ]
4 answers
Kit will work for that. double check the required cable lengths
[ JASON  Feb 20, 2014 ]
Absolutely. Crutchfield has thought of everything you may want to use in hooking up whatever system you choose, in any configuration. They have yet to miss anticipating the remotest need I may have in numerous setups over the years, and for a number of different vehicles.
[ DOUG  Feb 20, 2014 ]
You need additional patch cord to run 4 channel amp
[ CHRIS  Feb 19, 2014 ]
Yes it does. I used it for a 4 channel amp and a mono amp for a sub. It's a great kit, but I had to buy an extra roll of speaker wire to run since I was running a 4 channel amp. That would be my only complaint, because otherwise it's a great kit. You may not have to depending on your car make and the distance between the speakers and the amps.
[ KEVIN  Feb 19, 2014 ]

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