Fused Distribution blocks

[cichlid_baby 10+ year member]

Do people still use fused distribution blocks at the amps even though most amps are already internally fused and the main power line is also fused at the battery post?

Seems redundant.

I've heard that this practice has fallen out of favor as of late.

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[James Bang 5,000+ posts]

I'd still add a fuse before the amp. You can't be too careful with your electrical.

 

[Ctesibius 10+ year member]

Do people still use fused distribution blocks at the amps even though most amps are already internally fused and the main power line is also fused at the battery post?
Seems redundant.

I've heard that this practice has fallen out of favor as of late.

The fusing in a fused distribution block is to protect the wires, not the amplifiers.

 

[1hawaii50 10+ year member]

I have a fuse inline at the battery, and just use a non-fused distro block at my amps.

 

[cichlid_baby 10+ year member]

The fusing in a fused distribution block is to protect the wires, not the amplifiers.

Explain this for me...

I have 200 amp fused at battery running 2 gauge power back to a fuse block. Fuse block is fused with two 60 amp fuses running one 8 gauge power to the 4 ch amp and 4 gauge to the mono amp. Also have 8 and 4 gauge grounds to both amps respectively.

The amps are fused internally with 25 x 2 and 25 x 3.

If I were to have a battery short, would the fuses in the distribution block blow first or would the main power fuse blow, or would the internal fuses on the amp blow?

It would appear that the 25 amp internal fuses would blow first as they are the lowest rated, however, if you are telling me that the fuses in the distribution block would blow first then, infact they do serve a legitimate purpose in protecting the internals of the amps from the power/ground short.

I don't know.. this is why I'm asking.

I've seen some installs where the only fuses were the ones in the amp and the battery fuse.

 

[1hawaii50 10+ year member]

If you get a dead short in your power line, it is going to blow the fuse at the battery. This keeps your battery/power wire from catching your car on fire.

 

[cichlid_baby 10+ year member]

If you get a dead short in your power line, it is going to blow the fuse at the battery. This keeps your battery/power wire from catching your car on fire.

Why would the battery fuse blow? It's not the weakest link in install.

 

[1hawaii50 10+ year member]

Why would the battery fuse blow? It's not the weakest link in install.

A dead short in the power line has nothing to do with the weakest link in the install. It will blow the battery fuse because the battery is supplying the power. If you get a dead short in the power line, the short will "flow backwards" to the power (for lack of a more technical answer).

 

[audioholic 5,000+ posts]

Why would the battery fuse blow? It's not the weakest link in install.

You are forgetting that the short will be upstream from the internal fuses in the amp(s). The fuses in the amp would not even see the extra current flow generated by the short in the power wire. So the answer to your question is the fuse at the battery would blow.

The fusing in a fused distribution block is to protect the wires, not the amplifiers.

He already covered that by asking about the fuse at the battery.
Many people think that because the power wire after the distro block is so much shorter, that even though its a smaller gauge (assuming, as that is common) and is rated to handle as much or more power by looking at a wire sizing chart, that the fuse at the battery on the main cable will suffice for protecting the shorter, smaller gauge run of wire after the distro as well. I have even been guilty of making this mental mistake in the past, as have a few well respected and highly knowledgeable installers Ive asked in the past to confirm or deny. But, what is forgotten is a wire sizing chart is based on voltage drop (usually 2% or 5% allowable), NOT capacity ratings of the wires. Capacity is only affected by wire gauge, not run length, unlike a line-loss type wire sizing system. My point is, while a shorter run of a smaller gauge wire may be rated to lose less current than the longer run of the larger gauge wire, a wire CAPACITY chart will clearly show that the smaller gauge wire is rated for less current flow than the larger gauge wire. You could assume the line-loss sizing chart would take this into account and not recommend a size that physically exceeds wire current capacity, or you could play it safe and simply buy a fused distro block that allows you to size-down the fuses for individual runs of the smaller gauge wire, and not have to worry about it. This also gives an easy way to disconnect power to individual amplifiers in the system by simply pulling the fuse at the distro, which many times helps with troubleshooting, equipment swapping, etc. *shrug*

 

[Ctesibius 10+ year member]

He already covered that by asking about the fuse at the battery.

No, he didn't. If he had, then he would have understood that the fusing in a fused distribution block is to protect the smaller gauge wire at the reduction.

 

[audioholic 5,000+ posts]

No, he didn't. If he had, then he would have understood that the fusing in a fused distribution block is to protect the smaller gauge wire at the reduction.

God you enjoy arguing. lol

 

[Ctesibius 10+ year member]

God you enjoy arguing. lol

You apparently do as you attempted to find fault in my completely accurate comment that you actually expanded upon with your amp capacity post.

 

[audioholic 5,000+ posts]

You apparently do as you attempted to find fault in my completely accurate comment that you actually expanded upon with your amp capacity post.

Your refusing to admit fault in your comment has no bearing on my desire to argue. I wasn't even claiming your comment was wrong, but simply pointing out it was not really needed as the OP's further comments showed. But you are butt hurt over the 'SQ' thread, so you cant leave well enough alone. Keep flailing, it only shows how much I bother you, which really upset me so very much. No really, it does. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[Ctesibius 10+ year member]

Your refusing to admit fault in your comment has no bearing on my desire to argue. I wasn't even claiming your comment was wrong, but simply pointing out it was not really needed as the OP's further comments showed. But you are butt hurt over the 'SQ' thread, so you cant leave well enough alone. Keep flailing, it only shows how much I bother you, which really upset me so very much. No really, it does. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

//content.invisioncic.com/y282845/emoticons/laugh.gif.48439b2acf2cfca21620f01e7f77d1e4.gif

You are hilarious.

First, I really don't give a shit about you enough to carry it over to a different thread. I, in fact, responded to this thread first. You then responded to my post. So who is continuing what?

Second, my comment apparently was needed as, as I stated, if he had previously realized the function of the fuses in a fused distribution block he wouldn't have asked the question. The fuses are there to protect the wire, nothing else, as I stated and he apparently didn't understand. Although it's funny how you try to bring up comments made after my post to try to refute the relevance of my post as if I some how should have had a premonition about this thread.

You are apparently so butt hurt over the SQ thread that you felt the need to not give it a rest and attempt to carry your futile efforts to somehow discredit me into this thread. Keep playing your game, it won't get you anywhere other than proving how narcissistic and moronic you really are.

 

[audioholic 5,000+ posts]

//content.invisioncic.com/y282845/emoticons/laugh.gif.48439b2acf2cfca21620f01e7f77d1e4.gif
You are hilarious.

First, I really don't give a shit about you enough to carry it over to a different thread. I, in fact, responded to this thread first. You then responded to my post. So who is continuing what?

Second, my comment apparently was needed as, as I stated, if he had previously realized the function of the fuses in a fused distribution block he wouldn't have asked the question. The fuses are there to protect the wire, nothing else, as I stated and he apparently didn't understand. Although it's funny how you try to bring up comments made after my post to try to refute the relevance of my post as if I some how should have had a premonition about this thread.

You are apparently so butt hurt over the SQ thread that you felt the need to not give it a rest and attempt to carry your futile efforts to somehow discredit me into this thread. Keep playing your game, it won't get you anywhere other than proving how narcissistic and moronic you really are.

Your mom likes my narcissistic tendencies.