Fusing recommendations and wiring recommendations for amplifiers.

[Papermaker85 5,000+ posts]

I want to post this for everyone to read and understand a-little bit about fusing and the purpose of fusing and the real Trick to getting great output on higher powered systems.

First I want to say that I am a Certified Electrical and Instrumentation Technician. Make no mistake that these recommendation come for the NEC(National Electrical Code) and have been continuously researched for over 40 years.

Without getting into to much detail when you fuse you are A) protecting the wiring B) the device and the wiring.

That being said if you so choose to protect the device from Over-current you MUST A) use a wire rated to carry at least 125% of the total loads maximum current draw.. This IS VERY important

For example your common 2000 watts class D amp. Well designed and well built at maximum current consumption may be 290 amp @ 12.5 volts(always use the lowest voltage because chances are you voltage under a very heavy load will drop past 12.5) so 290x1.25=363 amps.

In that case Id suggest running one run of 4/0 and fusing 80% of maximum load ruffle 290 amps. Why? Because fuses by design will carry 100% of there load for several minutes. Under protection circumstances you want to fuse to provide adequate power but to blow before the power supply smokes. That being said the inconsistency of the fuses may require a=little more or less but its a starting point and without testing each fuse its impossible to really tell.

Remember 290 amps is still enough for the 2000 watts output continuously so its no issue under normal operating conditions even under moderate clipping you' re fine!

In the case you simply want to fuse the wire you simple choose the appropriate wire for the current draw.

This is a list of ampacity of wire. NOTICE that they have temperature ratings! These rating are based on the conductivity on the conductor the heat dissipation of the insulators and the type of installation the wire will be used in!

Most car audio wire is good wire. Don't be fooled by the claims of "over sized 1/0" its called 1/0 for a reason. Even though its larger is DOES NOT HANDLE more current. Wire is rated by "circular mil" if it says 1/0 its 1/0 granter they aren't lying about the actual surface area of the conductor.

HOW to figure what wire I need?

The manufacturer listed "recommended fusing" its pretty safe bet to follow it. So 200 amps. You want a wire that can handle 200 125% 250 amp. This gives you adequate head room and ensures VERY LITTLE VOLTAGE DROP.

Here is a link to a list of conductor ampacity and recommend fusing for said wire.

Wire Size Chart for Conductors in Free Air

A final though and real world testing. Most 2000 watt amps under normal conditions on a reactive load will never see its resting resistance. Impedance fluctuates with AC current and as heat builds up resistance rises.

What does this mean? Lets say you have a dual 2 ohm woofer, you wire it parallel of course to get one on NOMINAL.

You resting ohm should be 1-ohm. When you pass a varying signal like Ac(what speakers play) that rises. Typically between 1/2 the loads ohm up to 3x the load in the.

So your not getting close to the 2000 watts //content.invisioncic.com/y282845/emoticons/frown.gif.a3531fa0534503350665a1e957861287.gif At best you may get 1000 to 1500 watts so in reality you are drawing only around 150 160 amps instead of the 220 to 240 amps. That's pretty much worst case scenario so your wiring is PLENTY big.

That bring said don't try to down size your wire because your not getting the full 2000. Its foolish and hurts output and lower reliability on the gear from heat and voltage drop. You pay good money for a good amp DON'T buy undersized wire..

Click to read more...

 

[Boomin_tahoe 5,000+ posts]

This doesn't have anything to do with DIYMA/LosIsATool does it?

 

[Papermaker85 5,000+ posts]

This doesn't have anything to do with DIYMA/LosIsATool does it?

Naw man. It's something see people ask all to often.

Not only that its good to have a understanding as to what you are doing and why.

Said part is i learned alot from The forums in my early years. At that time industry leaders and engineers visited and shared a wealth of information. Now I see people who are taught wrong and don't have a real understanding of the real science and facts behind not only car audio but almost anything.

I did this so people can actually build a better more reliable system. Electrical in the last 10 years in car audio has become increasingly more important and its really a critical aspect as well as electronics in the field.

Just because it works doesn't mean it's the right way. There is a correct way to do things. This stuff is tested and its not guess work. Not to mention i HAVE to see people get ripped off or have problems when the information is available.

That being said im going to cover an array of topics. This was asked so I figured I do a small writeup.

Immediately make a list thats easy to read for the people who just want to see a chart and suggestions..

 

[audiobaun 5,000+ posts]

Vehicle Specific Mobile Electronics Wiring

There is lots of information here for those who take time to search and read.My learning experiences were more of trial and error/experimenting before the internet times. So much can be searched these days/google/You Tube/ ECT.

 

[Papermaker85 5,000+ posts]

Vehicle Specific Mobile Electronics WiringThere is lots of information here for those who take time to search and read.My learning experiences were more of trial and error/experimenting before the internet times. So much can be searched these days/google/You Tube/ ECT.

awesome. Also Id like to start a new topic for this. if you want you can and should

I also know of this site as well.

https://www.installdr.com/

 

[Papermaker85 5,000+ posts]

RMS power @ 1.5ohm/1ohm-------current draw @ 1ohm/@1.5ohm-----------Wire and (Fuse) 1ohm---1.5ohm @ 16ft

1200@1ohm/900@1.5 ohm---------138 Amps @1/103 Amps @1.5-------------#2(160amp)---#4(120 Amp)

2000@1ohm/1500@1.5ohm--------228 Amps@1/172 Amps@1.5---------------1/0(250amp)---#1(200 Amp)

2500@1ohm/1875@1.5ohm--------285 Amps @1/214 Amps@1.5--------------2/0(300amp)---1/0(250 Amp)

3000@1ohm/2250@1.5ohm--------342 Amps @1/257 Amps@1.5--------------2 #1s (2 200Amp)---3/0(300 Amp)

3500@1ohm/2625@1.5ohm--------400 Amps @1/300 Amps@1.5-------------- 2 1/0 (2 240Amp)--3/0(350 AMP)

The wattage and amperage and wire/fusing is for you average Impedance rise with a NOMINAL load of 1/2ohm and 1ohm. they are safe bets and will allow no more than 5% voltage drop and are for 12.5 volts. 14 volts will be roughly 12% less current consumption.

For example 3500/2625 using 14 volts would be 360/270 and would require realistically 2 #1s or a 4/0 and 2/0 wire

A Note about GOOD wire that is NEC rated and actually has an established legitimate rating. Southwire makes cable used for welding and several other applications that are actually above the NEC codes 90 degree insulator temperature rating its actually 105! so there 2/0 is actually goo for about 340 amps.. FYI the wire is call royal excelene.

 

[audiobaun 5,000+ posts]

awesome. Also Id like to start a new topic for this. if you want you can and should
I also know of this site as well.

https://www.installdr.com/

Thanks!! Booked!

 

[Boomin_tahoe 5,000+ posts]

RMS power @ 1.5ohm/1ohm-------current draw @ 1ohm/@1.5ohm-----------Wire and (Fuse) 1ohm---1.5ohm @ 16ft1200@1ohm/900@1.5 ohm---------138 Amps @1/103 Amps @1.5-------------#2(160amp)---#4(120 Amp)

2000@1ohm/1500@1.5ohm--------228 Amps@1/172 Amps@1.5---------------1/0(250amp)---#1(200 Amp)

2500@1ohm/1875@1.5ohm--------285 Amps @1/214 Amps@1.5--------------2/0(300amp)---1/0(250 Amp)

3000@1ohm/2250@1.5ohm--------342 Amps @1/257 Amps@1.5--------------2 #1s (2 200Amp)---3/0(300 Amp)

3500@1ohm/2625@1.5ohm--------400 Amps @1/300 Amps@1.5-------------- 2 1/0 (2 240Amp)--3/0(350 AMP)

The wattage and amperage and wire/fusing is for you average Impedance rise with a NOMINAL load of 1/2ohm and 1ohm. they are safe bets and will allow no more than 5% voltage drop and are for 12.5 volts. 14 volts will be roughly 12% less current consumption.

For example 3500/2625 using 14 volts would be 360/270 and would require realistically 2 #1s or a 4/0 and 2/0 wire

A Note about GOOD wire that is NEC rated and actually has an established legitimate rating. Southwire makes cable used for welding and several other applications that are actually above the NEC codes 90 degree insulator temperature rating its actually 105! so there 2/0 is actually goo for about 340 amps.. FYI the wire is call royal excelene.

Happen to have some of that stuff right here...

 

[Papermaker85 5,000+ posts]

Happen to have some of that stuff right here...

right on. its good wire. southwire is used world-wire by electrical contractors.now fuse that **** properly dammint.

truth be told id take the .2 volt loss and do circuit breaker //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[Boomin_tahoe 5,000+ posts]

The only reason I'm familiar with that wire brand is because when I worked at Genie, they use it a lot on their products: Scissor lifts, booms, etc. So I thought to myself, well **** if a huge company uses it, it must be good. I have since bought a few times of it and had no issues.

It's going in the Tahoe....the big 3. It's using 2 gauge now, same wire, and getting replaced with it. The 2 gauge is going into the s10 when I do the big 3 on it also.

 

[Papermaker85 5,000+ posts]

The only reason I'm familiar with that wire brand is because when I worked at Genie, they use it a lot on their products: Scissor lifts, booms, etc. So I thought to myself, well **** if a huge company uses it, it must be good. I have since bought a few times of it and had no issues.
It's going in the Tahoe....the big 3. It's using 2 gauge now, same wire, and getting replaced with it. The 2 gauge is going into the s10 when I do the big 3 on it also.

bigger the wire the better. wire ain't cheap but you spent 1grand on subwoofers spend 200 more on wire.

 

[Boomin_tahoe 5,000+ posts]

bigger the wire the better. wire ain't cheap but you spent 1grand on subwoofers spend 200 more on wire.

Both my subs were 530 bucks. That wire pictured was 55 bucks shipped. 10' lengths

 

[Papermaker85 5,000+ posts]

Both my subs were 530 bucks. That wire pictured was 55 bucks shipped. 10' lengths

you know what i mean assss

 

[Boomin_tahoe 5,000+ posts]

you know what i mean assss

Oh ok. Thought you really meant I spent 1k on my subs.