the12volt.com spacer
the12volt.com spacer
the12volt.com spacer
the12volt.com spacer
icon

power wire size?


Post ReplyPost New Topic
< Prev Topic Next Topic >
bumpn 
Member - Posts: 26
Member spacespace
Joined: November 17, 2014
Location: Georgia, United States
Posted: November 28, 2014 at 8:07 PM / IP Logged  
not sure about internal fuses. and yes, the wire from the dist. block is also 4 gauge. I have this amp on 1 fuse and a electronic crossover and a small amp for my components on another separate fuse.
bassss!
oldspark 
Gold - Posts: 4,913
Gold spacespace
Joined: November 03, 2008
Location: Australia
Posted: November 28, 2014 at 9:30 PM / IP Logged  
So another amp also from the DB thru a fuse?
You can have the amp protection fuse at the battery keeping in mind that it now covers BOTH amps (ie will operate on the sum of the amps plus the small amp's current).
And again, the amp's manual should say what size (& type) of fuse(s) it has, else specify what type you need to provide.
But DO NOT confuse a load's (amp's) protection fusing with that of the distribution. Many loads may have fast-blow fuses (slow blows aren't a problem - it just means the distribution fuse may blow instead).
And re fuse voltage drops, the real dedicated use non-resistive circuit breakers (magnetic sensing) as they are effectively an in line relay as opposed to a resistive protection device.
Of course, good high-power amps should not vary output power as a result of reasonable voltage dips - ie of up to a few volts.
bumpn 
Member - Posts: 26
Member spacespace
Joined: November 17, 2014
Location: Georgia, United States
Posted: November 28, 2014 at 10:48 PM / IP Logged  
ok. so I looked up the manual for my amp and it calls for a 35 amp fuse. so if I have a fuse at the battery and one at the dist. block,i would need like a 20 amp fuse at the battery and a 20 at the dist. block instead of putting like a 30 or 40 amp fuse in each end..right?
bassss!
oldspark 
Gold - Posts: 4,913
Gold spacespace
Joined: November 03, 2008
Location: Australia
Posted: November 28, 2014 at 11:30 PM / IP Logged  
No - fuses in series are not "additive". EG - 30A passes thu both so both would be overloaded.   
Normally the 35A amp protection fuse would be in the amp, but for recalcitrant fuseless designs you'd place it near the amp power terminals.
Your distribution fuse - eg, 100A or whatever - then protects the distribution (until the next downstream fuse).
If you have to provide your own fuse, or if you want a single fuse, then you'd use a 35A fuse for distribution (even if using 100A cable etc). But then you would probably go direct to the amp rather than the added hassle and cost of a DB.
Any low power loads could then be taken off the amp power input.
What amperage or power is the other amplifier?
bumpn 
Member - Posts: 26
Member spacespace
Joined: November 17, 2014
Location: Georgia, United States
Posted: November 29, 2014 at 12:08 AM / IP Logged  
the other is only a 50 watt x 2 that I have wired in stereo.
bassss!
oldspark 
Gold - Posts: 4,913
Gold spacespace
Joined: November 03, 2008
Location: Australia
Posted: November 29, 2014 at 1:42 AM / IP Logged  
So that's an extra 20% on the 500W amp.
So you could use your DB with (say) 100A (of 4G) to each and a fuse up to 100A (or rated for the 4G) at the supply/battery end with fuses - if needed - for either/both amps at their power terminals...
Most would use a big fuse for the cable to the DB and then smaller fuses (and wires) more suited to each load at the DB ouputs.
Or if the 500W requires you to supply its 35A fuse, a 35A fuse at the battery end (that assumes the 2x50W = 100W amp has its own fuse). But the if the 100W draws 10A, the 500W amp can only draw up to 25A.
BTW - fuses will typically handle 10% over-current for at least several hours - ie, a 35A might handle 40A for hours or 45A for many minutes. However, as before, running above say 70-80$ of fuse rating decreases the life of the fuse. And several overloads of say 110% or 120% will cause accelerated failure even if it survives each individual overload (ie, thermal fatigue).   
bumpn 
Member - Posts: 26
Member spacespace
Joined: November 17, 2014
Location: Georgia, United States
Posted: November 29, 2014 at 4:10 AM / IP Logged  
ok. sounds like I may need to start out with like a 50 amp fuse at the battery and a 35 at the dist. block for starters. the small amp has the factory original inline fuse holder for it.
bassss!
soundnsecurity 
Gold - Posts: 2,711
Gold spaceThis member has made a donation to the12volt.com. Click here for more info.spacespace
Joined: November 10, 2008
Location: Louisiana, United States
Posted: November 29, 2014 at 10:40 AM / IP Logged  
if your main power run from battery to distribution block is 4 gauge then i would use a 60A fuse as my main to allow full current to pass through to each amp being powered from that main power wire, then at the distribution block i would use the recommended fuse for each amp.
the main fuse is there to protect the wire against burning up from being shorted and your fuses in the DB will protect the amps.
Page of 2

Sorry, you can NOT post a reply.
This topic is closed.

  Printable version Printable version Post ReplyPost New Topic
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot delete your posts in this forum
You cannot edit your posts in this forum
You cannot create polls in this forum
You cannot vote in polls in this forum

  •  
Search the12volt.com
Follow the12volt.com Follow the12volt.com on Facebook
Thursday, March 28, 2024 • Copyright © 1999-2024 the12volt.com, All Rights Reserved Privacy Policy & Use of Cookies
Disclaimer: *All information on this site ( the12volt.com ) is provided "as is" without any warranty of any kind, either expressed or implied, including but not limited to fitness for a particular use. Any user assumes the entire risk as to the accuracy and use of this information. Please verify all wire colors and diagrams before applying any information.

Secured by Sectigo
the12volt.com spacer
the12volt.com spacer
the12volt.com spacer
Support the12volt.com
Top
the12volt.com spacer
the12volt.com spacer