Cable gauge chart

How to determine the best size wire for your amplifier's power and ground


Buck Pomerantz

Buck Pomerantz was born and raised in Philadelphia. His parents bought their first television set when he was born. He figured out how to run it by the time he was two. Besides athletics, his formative interests included electronics, amateur radio, music, and stage crew work. He got his BA in writing from Brown University. Then he joined a rock 'n roll band as their soundman and moved to Charlottesville, Virginia. After that venture failed, he spent time in Boston, New Orleans, and Berkeley. He worked in a music store in Austin manufacturing, installing, repairing, and operating sound systems for recording studios, clubs, and bands. He moved back to Charlottesville, ran a little recording studio and finally joined Crutchfield as a copywriter. He has 2 grown children and 3 grandchildren, but after a good nap he can still rock out.

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T-Spec power and ground cables

T-Spec wires and hardware ensure full current flow for your amplifier

In order to operate correctly, an amplifier needs its power and ground wiring to be large enough to accomodate its demand for electrical current. What gauge (thickness) wire to use for power cabling depends on how much current your system will try to consume, and on how long the wiring run will be.

The formula for current draw

To determine the approximate current draw (in amperes) of your amplifier (or amplifiers), you must first calculate the total power of the system (multiply the number of channels by the number of RMS watts per channel). If you have multiple amps, add up the total power figures to arrive at a grand total. Next, double your grand total power figure. Then, divide by 13.8.

Total RMS Wattage times 2 (Inverse of Amp Efficiency) divided by 13.8 Volts equals Current Draw in Amperes  (explanation below)

The resulting figure is your system's approximate maximum current draw. Compare this number to the numbers in the "Amperes" column in the chart below. Cross-reference with the cable length (the distance from your battery to the amplifier's mounting location) to determine which gauge of cable you need.

Once you have estimated the total amperage of your system using the described formula, determine the proper power and ground wire gauge from this chart based on the length of power cable your installation requires. Please note that  the smaller the gauge number, the larger the wire. 1/0 ("one-aught") is the common name for a 0-gauge wire; 2/0 ("two-aught") for a 00-gauge wire.

Cable gauge chart

A more detailed explanation

Here is an explanation about the formula we use, in case you want more details. Calculating the amplifier's total power is straightforward, but the other two parts can be confusing.

No amplifier is 100% efficient

First of all, why do we double the total power figure? That's because the typical analog amplifier is about 50% efficient. That means about half of the power it generates is turned into audio output while the other half of the power is lost as heat.

So if your amplifier is putting out 400 watts, it's actually drawing about 800 watts of power from its source, and the amp's wiring needs to be big enough to handle that draw. (Class D amplifiers are much more efficient in comparison, but it's still safest to go with the larger wire size.)

Automotive voltage is neither 12 volts nor 14.4 volts

And the 13.8? Yes, vehicles have a 12-volt electrical system, but we're assuming that the vehicle is running — which means its alternator will bump up the system voltage to about 13.8 volts. This is a better real-world representation of the vehicle's electrical supply. Dividing by 12 results in a larger number, which could point to a larger wire gauge, but it's often in the same color range in the chart. Manufacturers use 14.4 volts, when they spec their gear, to exaggerate their power ratings.

Resistance increases with length

The reason different cable lengths bear different ratings is because the electrical resistance, inherent in all wire, builds up as the cable gets longer, until it forces the voltage to drop below a useable level. At that point, up-sizing the power cable will restore the voltage to its intended level.

Size matters for current flow

Finally, according to our tech support guys, the primary performance limitation in most amplifier installations is in the current delivery — either a weak ground or insufficient wire gauge. Installing too small of a wire gauge results in poor performance, potentially shorter service life of connected components (your amplifier and speakers), and a potential safety hazard.

On the other hand, installing too large a wire gauge doesn't really have any downside, and there is the potential for better performance. Obviously, there's no need to buy 2-gauge wiring when 10-gauge will do. That kind of overkill would be a waste of money. But if the chart could lean either way between two sizes, going with the larger wire size would be the smart choice.

  • Hector Perez from United States

    Posted on 5/10/2015 9:37:09 AM

    how far I have to install my fuse to my amp?

  • Buck Pomerantz from Crutchfield

    Posted on 5/11/2015 10:06:53 AM

    Hector, The fuse in an amplifier's power cable should be installed as close to the battery as possible, within 6" ideally. In case of an accident, you do not want a live wire stretching throughout your vehicle - that could lead to a fire. Many people with multi-amp systems also fuse the individual power wires running to each amp. They most often do that with a fused power distribution block.

  • gregory from jamaica

    Posted on 5/13/2015 9:37:02 AM

    hey good day guys i just check my system using the calculator and from what i am seeing is i will be drawing about 400+ amps. i had run 2 gauge wire from my battery to my distribution block and on the chat its saying i should have 0 gauge wire,, could i run another 2 gauge wire from the battery to the distribution block or do i have to change it out and get the 0 gauge

  • Buck Pomerantz from Crutchfield

    Posted on 5/14/2015 9:16:40 AM

    Gregory, I doubt any vehicle's electrical system will allow you to draw 400+ amperes from it without enhancements like extra batteries and a high-output alternator. This amount of current means your amplifiers are capable of 2,760+ watts RMS output. If this is truly the case, then even 1/0-gauge power and ground wires won't be large enough to safely pass this amount of power. I would suggest using 3/0-gauge (000-ga.) wire for this size application. Even two 2-gauge wires wouldn't be large enough for 400 amperes.

  • Blake from Colorado

    Posted on 6/17/2015 2:01:29 PM

    Great information here, but I am still not sure which gauge to use. I have an AudioBahn A4002T amp that will be going into a 97' Subaru Impreza Outback Sport. Its also about 14' long bumper to bumper so my length would prolly be much shorter than that. The Amp's manual says this: 800 watts ACH Power 100 watts x2 @ 4 Ohms RMS Power 200 watts x2 @ 2 Ohms RMS Power Also tho this website: [Link removed] said that it has an "Output Power / Total: 400 Watt" hence the confusion. Could you clarify on what gauge I would most likely need? Thanks, Blake

  • Buck Pomerantz from Crutchfield

    Posted on 6/17/2015 3:55:13 PM

    Blake, This amplifier's power is right on the edge of two cable sizes, so it will depend on how you use the amp. If you want to drive two 4-ohm speakers: 100 watts RMS x 2 channels = 200 watts RMS total; 200x2/13.8 = 29 amperes; you'd need 10-gauge power and ground cables. If you want to drive two 2-ohm speakers, or want to bridge the amp to run a 4-ohm subwoofer; 400 watts RMS x 1 channel; 400x2/13.8 = 58 amperes; you'll want 8-gauge or 4-gauge wiring, depending on the length needed.

  • mike johnson from champlin, MN.

    Posted on 6/22/2015 9:25:56 PM

    I have installed a 500 watt amp that is 25 feet away from the CAP, it is driving two 12 inch subs and seems that i have installed the wrong power supply wire to the AMP can you help me? and do you have the wire size in stock? will need 30 feet

  • Buck Pomerantz from Crutchfield

    Posted on 6/23/2015 11:14:52 AM

    Mike, I'm not sure you need a capacitor for a 500-watt system, but a capacitor usually gets installed as close to the subwoofer amplifier as possible to be effective, not 25-feet away. 30 feet is awful long - is this an RV or bus? If you don't plan on ever expanding the system or your amplifier uses Class D amp technology, then 4-gauge power and ground wires will do. Otherwise, I'd use 2-gauge power and ground wiring. Crutchfield presently carries 4-gauge wire, but not 2-gauge.

  • Joey from US

    Posted on 6/29/2015 10:46:14 AM

    I made the mistake of buying a cheap walmart brand wire, I originally ran my 1600 watt amp with a 1200 watt power wire, but i sold the wire along with that jeep, So i put my 15" L7 and 1600 watt amp in my truck and thought i could skirt by on that, I just blew 3 fuses in the last 5 minutes, 2 80 amp 1 100 amp. I figure it to be the wire cause the amp works just fine... So what gauge wire should I be using?

  • Buck Pomerantz from Crutchfield

    Posted on 6/30/2015 10:52:15 AM

    Joey, Without knowing the specific model amplifier I can't be sure, but if your amplifier really is capable of putting out 1600 watts RMS of power (RMS not peak), according to this article's formula and chart it needs either 2-gauge or 1/0-gauge wiring, depending on the length. You'd also need a 200-amp to 250-amp fuse to protect your wire and vehicle from fire in the event of a short circuit.

  • Ryan from missouri

    Posted on 6/30/2015 2:17:13 PM

    Should you rate the wires from the distribution block to the amp separately? For example, If you have a two amplifier system pulling 91 amps with 12ft of cable you need 4-ga from the battery all the way up to the distribution block. Once you branch off, the amps are pulling 43 and 48 independently. At 4 feet does this mean it only requires two 10-ga wires?

  • Buck Pomerantz from Crutchfield

    Posted on 6/30/2015 4:24:58 PM

    Ryan, You are correct. Running a 12-foot 4-gauge wire from the battery ensures that all 91 amperes of current will arrive at the distribution block. Running a 4-foot 10-gauge wire for each amp will also guarantee adequate power flow to each amp.

  • Dylan

    Posted on 7/8/2015 9:02:00 AM

    Just to let you guys know... you have "+ 13.8" not "/ 13.8" written for your formula

  • Buck Pomerantz from Crutchfield

    Posted on 7/8/2015 10:40:20 AM

    Dylan, If you look a little closer at that symbol you should be able to see that it's an old-fashioned "divided by" sign - a horizontal line with a dot above and a dot below. Sorry if that's unclear.

  • David B from Phoenix

    Posted on 7/19/2015 8:14:16 PM

    I find it hard to believe the typo in the formula on the page. You might want to change the plus sign to a division sign ;)

  • Buck Pomerantz from Crutchfield

    Posted on 7/20/2015 9:20:19 AM

    David, Seeing as you are the second commenter who read that "divided by" sign as a plus symbol, I am going to rewrite the formula in English, with no mathematical symbols. This way, even if someone should read it on a small screen like a phone, there will be no misunderstanding. Thanks for pointing it out.

  • neville from harare ( zim )

    Posted on 7/22/2015 4:09:37 AM

    Good day I got a 8000 watt amp and two 2000 watt sub's my distance from batt is about 3 meters can I use a 0 gauge cable with a 3.2 farad capasitor.

  • Buck Pomerantz from Crutchfield

    Posted on 7/22/2015 2:36:12 PM

    Neville, I suspect that huge power rating you quote is a peak or maximum specification, which is useless for planning out a sound system. You should use RMS ratings only. Ten feet (3 m) of AWG 0-gauge wire (50 square mm) should be able to supply adequate current for a 2500 watts RMS amplifier.

  • allen from lansing

    Posted on 7/26/2015 12:32:33 PM

    Okay I have two amplifiers in my car. I have one 2000.2 autotek amp. 1000 watts per channel or bridged 2000 watts at 2 ohm steady. I went through a lot of problems thinking I had smaller wire because my protect was going off. Now I have 2 gauge lead power with 4 gauge ground. ( turned out a speaker was blown. Second I have a old black lanzar 2100 optidrive competition and with a 45db boost. It is running bridged mono. That runs on same ground but a 6 gauge lead wire. I want to get rid of wires. Can I run both the amplifiers on the same 2 gauge wire running to there full capacity even if I have to But a capacitor and if so what fared? I have been told by a friend if I run both on the same 2 gauge the wire will not handle both amps. I want to split the wire into a snake tongue to each amp. I own a 2000 dodge neon manual 2.0l. The 2 gauge is 18 ft long.

  • Buck Pomerantz from Crutchfield

    Posted on 7/27/2015 12:37:38 PM

    Allen, I can get very little trustworthy information about your amplifiers, plus not knowing what you intend to run with them makes it difficult to give an exact answer. But I think running one 1/0-gauge power wire from your battery to a distribution block will work. From the distribution block you'll need to run 4-gauge power wires to each amp and 4-gauge ground wires from the amps to your chassis connection. If you think you need a capacitor, check out the 3.0 Farad model.

  • Ryan from Louisiana

    Posted on 7/28/2015 1:01:56 AM

    I have an amp and aftermarket door speakers that were already installed in my truck when i got it. No idea what brand, wattage, or impedance the speakers are. Amp is an outdated Alpine 4 channel that puts out 70rms/channel at 4 ohms and 100rms/channel at 2 ohms. I just ordered 2 P1 subs with 250rms and a 500rms amp that should push full power when wired at 2 ohms. My question is how do i tackle wiring these systems when I don't know what one really is but know exactly what I need for the other? And would it matter if the old amp is set at 4 ohms and the new one is 2? I know speakers of different impedance cant be hooked to the same amp but not sure if it matters that two amps are set differently

  • Buck Pomerantz from Crutchfield

    Posted on 7/28/2015 3:22:39 PM

    Ryan, Almost all aftermarket car speakers have a nominal impedance of 4 ohms. You don't set an amplifier to an impedance - you hook up a 4-ohm speaker to an amp, and voila: the amp is pushing a 4-ohm load. Rockford Fosgate P1 subwoofers come in SVC 4-ohm and SVC 2-ohm models. Not knowing which ones you have, or what amp you have make it impossible to give advice on how to wire them together. If you want a question answered about your system, you must identify your equipment by brand names and model numbers.

  • Jason from Idaho Falls

    Posted on 8/3/2015 12:10:34 PM

    Just checking my math and making sure I'm not going to melt anything in my pretty black 2009 Impala LT. I have an AR1500M Boss amp rated at 1500w peak and 700w RMS running at 2ohms on an Infinity 12" sub with 2 voice coils at 4 ohms at 2500w peak. I'm not sure what the RMS is but I' was thinking it would be underpowered. I have a BOSS Audio KIT2 8 Gauge (sold bundled with the amp) run through the car and I didn't trim any yet but there is a good 6Ft of cable left in the trunk. Haven't hooked anything up yet... My question is this... Will that cable safely handle the power output of the Amp/sub combo Or am I looking at getting something a bit more substantial? Let me know if I missed any details.

  • Buck Pomerantz from Crutchfield

    Posted on 8/3/2015 12:48:41 PM

    Jason, Judging by that amp's single 30-amp fuse, I think that the 8-gauge kit it came with will be okay, in spite of the math using the published specs. You could upgrade to 4-gauge cable, so you wouldn't have to re-wire if you got a stronger amp in the future.

  • Jason from Idaho Falls

    Posted on 8/3/2015 2:05:08 PM

    Thanks, that was a far faster response than I had expected. I'm just adding a bit of punch to the already existing stock sound setup. I likely will sell the car with the amp in it. There were a lot of factors that went into picking something that would sound nice and not overpower the stock speakers. I will likely be using this amp at no more than 35% volume tuned in relation to the factory setup.I was thinking that Boss was being a bit generous with their spec but a second opinion doesn't hurt.

  • Joshua from Los Angeles

    Posted on 8/5/2015 12:33:04 PM

    I have two 4 Ohm Alpine Type R's, wired down to 1 Ohm with a 1900.1 Brutus Amp, with 4 gauge lead and ground wire , with a 300 amp circuit breaker , my amp only has two 60 amp fuses in it , should this give me any problems ? Or would it be fine as long as the amp isn't using the full 300 amps

  • Buck Pomerantz from Crutchfield

    Posted on 8/5/2015 1:28:04 PM

    Joshua, The fuse or circuit breaker on your power wire protects the wire and your vehicle from fire in the event of a short circuit. A 4-gauge wire, under this circumstance, will burn your car to the ground before a 300-amp circuit breaker will trip. Please, for your safety, replace that 300-amp breaker with a 100-amp fuse or breaker as soon as possible. And be sure to mount it as close to the battery as you can.

  • Shawn from Columbus

    Posted on 8/6/2015 11:28:16 AM

    After reading this I thought about getting new thicker cable. But after doing some digging and getting specs on my amp fuse and fuse in the holder, my issue became no concerned. After some thought it wouldn't be ideal to run 0 Gauge wire. According to the steps to figure your amperage there is no way that calculation is correct. The calculation states in pulling 159 amps, if that is so, then my 100 anl fuse in my power cable would have 'popped', and or my amp fuse of 80 amps would've as well. This calculation is just a calculation, to accurately find your amperage being 'pulled' a multimeter is your best bet to find the truth. I am running a Hifonics bxr.1116.1d on 4 gauge wire, wired in a 1 ohm load powering two NVX VCW124's. I have two power capacitors an 8 farad Soundstream and a 1 farad NVX, but the capacitors won't affect amperage being pulled. Plus before I installed the Caps no fuse blowing was occurring. My wire is not cut down due to having the Caps and I actually added an extra 5 feet or power and ground to accomodate both caps for placement. So realistically I have approximately 23 feet or power wire.

  • Buck Pomerantz from Crutchfield

    Posted on 8/6/2015 4:45:20 PM

    Shawn, According to Hifonics, that amp should have two 60-amp fuses onboard, 120-amps total. This Cable Gauge article uses a typical 50% efficient AB amplifier as the basis for the formula for finding current draw. But your amp is Class D, which is more efficient. Instead of multiplying the total RMS output by two (the inverse of its 50% efficiency), for your amp we can multiply it by the inverse of 75% instead, and come up with a more accurate rating of 106-amps. If you play loud test tones constantly, your 100-amp fuse may become stressed. But if you play music, which only draws full power about one third of the time, then your 4-gauge wire and 100-amp fuse are A-OK.

  • Ragnar from Tórshavn

    Posted on 8/17/2015 12:39:49 PM

    I will be running a JBL GTO-5EZ with my factory head unit using a low line converter. On JBL's website it says that the peak power is 1935 watts. This means I will be running 280 amps, and would 2 gauge wire be enough?

  • Buck Pomerantz from Crutchfield

    Posted on 8/17/2015 2:31:22 PM

    Ragnor, Like this article says you should only use RMS ratings for system-planning, not peak ratings. That amplifier can put out four channels of 75 watts RMS and one channel of 500 watts RMS at 2 ohms. 4 times 75 equals 300; plus 500 totals 800 watts RMS. Now, using the formula for current, you'll find the amp will draw a maximum of 116 amperes. 4-gauge power and ground wires will work perfectly well for that amplifier.

  • cameron from richmond

    Posted on 8/22/2015 6:09:54 PM

    I have a question I have two 12 pioneer pro champion series subs there rated at 2500 watt peak an 1000rms I also have a 5500 watt power acustic amp not sure what it's rms is was woundering what wire I should use to wire it in correctly

  • Buck Pomerantz from Crutchfield

    Posted on 8/24/2015 10:35:48 AM

    Cameron, That amplifier calls out for 1/0-gauge power and ground wiring.

  • frank from Riverside

    Posted on 8/26/2015 6:35:20 PM

    Question: I'm going to atemp to rewire my old car and go from 6volt to 12volt what gauge wire do I use or can I use the 14 gauge wire from when it was wired before?and just change the bulbs,coil,battery and to alternator.

  • Buck Pomerantz from Crutchfield

    Posted on 8/27/2015 10:05:11 AM

    Frank, If you're asking about the standard wiring in your car and not about an amplifier's power wiring, then I think 14-gauge wire ought to work just fine. However, keeping in mind that it's been about 60 years since American cars used 6-volt systems, the original wiring may need replacing anyway.

  • Ryan from edmond

    Posted on 8/29/2015 3:44:43 AM

    Hello, I am purchasing a new setup and I am interested in setting them up myself. see if my research is in balance. I purchased 2 Pioneer TS-W3003D4 Champion PRO 2000 Watt MAX 12" Dual 4 Ohm subwoofer + Pioneer GM Digital Series GM-D9601 2400 Watt Monoblock Class D Car Amplifier. Based on the chart I stand within the 4 gauge or 2 gauge wiring for my subaru wrx.

  • Josh Holohan from Isle of Man

    Posted on 8/30/2015 6:28:23 PM

    hi there i have a set of vibe qb69 at 200w rms each and a sony explode 12 inch sub at 350 watts rms and was going to buy an amp which is 1000watts rms (Lanzar HTG447) would a 8 guage wiring kit fitted with a 60A fuse be okay to power it the amp is fitted with 2 25A fuses Many thanks Josh

  • Buck Pomerantz from Crutchfield

    Posted on 8/31/2015 10:43:36 AM

    Ryan, The owner's guide for your amplifier recommends 4-gauge power and ground wiring.

  • Buck Pomerantz from Crutchfield

    Posted on 8/31/2015 12:04:46 PM

    Josh, The owner's manual for that amplifier recommends either 8- or 4-gauge power and ground wiring. I'd go with the 4-gauge to ensure power delivery. Use whatever size in-line fuse that comes with your wiring kit. That fuse protects the wire and your car. The fuse on the amp protects the amp.

  • Ryan Reeves from Galveston, TX

    Posted on 9/4/2015 4:43:21 PM

    Mr. Pomerantz, I have installed a Rockford Fosgate R1200-1D pushing two Rockford Fosgate P3D4-12's wired at 1 ohm. I recently "melted" the power wire where it connects at the fuse holder. Not between the battery and fuse holder. But after the fuse holder leading out towards the amp. The fuse holder showed signs of heat and the wire in the clamping part/set screw of the holder was brittle and broken. The wire is true AWG A spec size 4 gauge for power and ground (Lightining Audio LA-4i Amp Kit). Could you please point me in the direction of potential causes? I'm positive that I have a good "solid" ground with all paint removed. Do I need to drop down to a -0- gauge kit, or larger if necessary? Thanks in advance for your wisdom.

  • Buck Pomerantz from Crutchfield

    Posted on 9/5/2015 3:36:25 PM

    Ryan, What you describe is often caused by a loose connection of a power wire. And it sounds like that connection is at the fuse holder. When an electrical connection becomes intermittent, cutting in and out, the resistance to the current flow creates great heat, sometimes even sparks - a dangerous condition. You need to tighten all your power and ground wire connections. Maybe you even need to replace that fuse holder too.

  • greg street from oronogo mo.

    Posted on 9/7/2015 8:18:59 PM

    i have an older 600 watt alpine mono amp. and i was wondering what size fuse should i use on the power wire. im just running a type r 12 in. comp sub. alpine also i am using the biggest power wire the stereo shop had which is big but not sure what gauge it was. its clear coating on wire

  • Buck Pomerantz from Crutchfield

    Posted on 9/8/2015 1:30:23 PM

    Greg, The in-line fuse on the power cable is there to protect the wire and your vehicle, so you need to know the size of the wire in order to know what size fuse to use. You should return that power wire to your stereo shop and get a proper amplifier wiring kit with cable and fuse that match your amp. A 4-gauge kit will probably work.

  • Haden wilson from Eatonton

    Posted on 9/18/2015 9:37:04 PM

    I have 2 alpine type r 10's that are dual 2 ohm voice cool subwoofers run off a pioneer 2400 watt amp. Would 4 gauge be efficient enough to power the amp? Secondly I am thinking about swapping the 2400 to the planet audio 5000.1 to run at 2 ohms to send roughly 1250 watts to each sub, will I have to swap the wiring out to a larger/thicker wire?

  • Buck Pomerantz from Crutchfield

    Posted on 9/19/2015 10:30:11 AM

    Haden, If you're referring to the Pioneer GM-D9601 amplifier, 4-gauge will do. But that Planet Audio amp will need 1/0-gauge power and ground wiring.

  • James Shanley from Ballwin

    Posted on 9/21/2015 11:45:27 PM

    Ok I will list components and see what you think. I currently have a run of 2 gauge welding cable ran to the rear kinetik 2000 blue series. From that battery I have the same 2 gauge wire to the amps is this good enough? Second I just bought another t1000.1 and was wondering if the kinetic 2000 is enough and is the 2 gauge from the front battery good enough? I have a stock 130 amp alternator by the way

  • Buck Pomerantz from Crutchfield

    Posted on 9/22/2015 10:41:52 AM

    James, I can't tell, by your description, how many batteries or amplifiers you have in your system, nor what exactly each amp is, so I can't help you with your wiring. Whatever you do, make sure to install an inline fuse on each power cable within a few inches of each battery.

  • Walker J from Kelowna

    Posted on 9/25/2015 11:16:08 AM

    Hey Crutchfield, thank you for all the awesome information. I am installing a Hertz HDP4 amp, it is a full 17 Ft cord length right now. I have 4 gauge Stinger True-Spec, so I think I'm good there. However if I adder another 600 rms Hertz subwoofer, would I still be okay? I'll distribute the 4 gauge at 17 ft, then run 8 gauge to the seperate amps. We can assume my new amp at 600w rms will be Class A/B. My other question for you guys is this, what gauge wire do I need for my Hertz 165XL door speakers? They run 150 rms. Thanks so much for your guys' time and efforts.

  • Buck Pomerantz from Crutchfield

    Posted on 9/25/2015 3:31:22 PM

    Walker, If you want to run those two amplifiers at the same time you'll need to use 1/0-gauge wire from the battery to a distribution block, otherwise they won't be able to draw full power. From there you should be okay with short runs of 8-gauge. As for speakers, 14- or 16-gauge wires are fine.

  • Andrew from muncie

    Posted on 9/29/2015 11:32:09 PM

    my amp is a mon block capable of 2000watts rms but the power input on the amp only takes 4 guage. makes no sense to me

  • Buck Pomerantz from Crutchfield

    Posted on 9/30/2015 10:41:06 AM

    Andrew, Welcome to the world of car amplifier marketing, where the rating printed on the amp is often an exaggeration.

  • Brandon from Seattle

    Posted on 10/1/2015 12:21:44 AM

    Great article. I think I have this all correct in my head, but i'm not sure. I am now getting conflicting information out there on the WWW in car audio forums. Maybe you can clarify? I am running 2 amps, and driving all 4ohm speakers. One amp is 100x2 rms, and the other is 300x2 rms. The smaller amps says it has a fuse rating of 50a. The larger says it has a fuse rating of 140a. The primary power wire I have run, is a 0 gauge, and I Just need to figure out what size ANL fuse to put in the fuse box. From what I have read here on crutchfield, I simply add the fuse ratings together to arrive at my total, for the power wire up at the battery... which is 190amps. I can't buy a 190a ANL, so a 200 is what I am planning on putting in. Then between the distribution block and each amp, I have planned a 40amp ANL for the smaller, and a 150 ANL for the larger. Correct?

  • Buck Pomerantz from Crutchfield

    Posted on 10/1/2015 11:12:03 AM

    Brandon, The inline fuse on the power cable near the battery is there to protect you and your vehicle from a fire in the event of a short circuit. The size of the fuse depends only on the size of the power wire. Of the1/0-gauge amp wiring kits Crutchfield sells, one manufacturer includes a 300-amp fuse, and another includes a 250-amp fuse. Your 200-amp fuse will work as well. If your amps have onboard fuses, no other fuses will be necessary. If your amplifiers do not have onboard fuses, you should fuse each power line after the distribution block with a fuse as near as possible to the specified size.

  • Brandon from seattle

    Posted on 10/1/2015 1:03:11 PM

    Thanks for the information, Buck. Unfortunately, you guys have some conflicting information right here on your website. Here is a quote from your amp article where the question is asked "what size fuse do I need for my amp"? [Link to Car amplifier FAQ] Q: How big should the fuse be? A: If you're installing just one amplifier, the fuse at the battery should simply match or slightly exceed the fuse rating of the amplifier itself. Some amps don't come with onboard fuses - you have to find their fuse ratings in their owner's manuals. If you're installing two or more amplifiers, just add their fuse ratings together and install a fuse rated roughly equal to this sum. Generally, it's better to go slightly higher than lower, but a margin of five amperes is acceptable. Say you have three amplifiers, two with fuse ratings of 20 amps each and one with a fuse rating of 25 amps. In this case, you can safely go with either a 60 or 70 amp fuse. Of course, if your system is powerful enough to demand that you install a heavy duty fuse, it's important that your power and ground wire be of an appropriately heavy gauge as well."

  • Buck Pomerantz from Crutchfield

    Posted on 10/1/2015 4:00:46 PM

    Brandon, It does look like you've uncovered a contradiction in my own advice. Although I think the information in the Car Amplifier FAQ may need updating, I am going to ask our Tech Department for their definitive answer. Stand by.

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