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10 gauge ok?

Printed From: the12volt.com
Forum Name: Relays
Forum Discription: Relay Diagrams, SPDT Relays, SPST Relays, DPDT Relays, Latching Relays, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=61136
Printed Date: May 10, 2025 at 1:10 PM


Topic: 10 gauge ok?

Posted By: mrkastro
Subject: 10 gauge ok?
Date Posted: August 11, 2005 at 4:58 AM

hello and thanks for your opinion.

im working an install similar to the laptop install someone has in this forum and i'm not so sure about the wire gauge i would like to use.

my thought was to use a toggle switch to trigger a relay for the power inverter.

so the doubt is, for the switch: 16 awg (85) 12v and 16awg (86) ground.

      now the 12v on (30) and (87)........................ is it ok to use a 8 or 10 awg????




Replies:

Posted By: hotwaterwizard
Date Posted: August 12, 2005 at 12:12 AM

How many Amps does the Inverter Draw?

How many Amps does the Computer Draw?



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John DeRosa (Hotwaterwizard)
Stockton California
When in doubt, try it out !




Posted By: boulderguy
Date Posted: August 12, 2005 at 1:01 AM

Unless that's a huge freakin' computer you're not going to need the 10g.  If that's the only thing on the inverter I'd say 16g is fine, but it'd help to know the amp/watt consumption of the unit & how many ft the wires run.  You're not running a hair dryer or a margarita machine are you?  Big plasma screen?





Posted By: hotwaterwizard
Date Posted: August 12, 2005 at 8:52 AM

How can you say that without even knowing the Amp Draw?

The relay coil is less than 1 amp so 16 ga will be fine there but , you need to think about the total Amp draw of the Inverter and the computer combined.

My old Inverter use to Draw 15 amps in idle.

My Fathers Inverter was 30 amps without a load and it ate 10 ga wire for lunch. The cigarette lighter plug melted.

If you don't do the math right you could start a fire under the Hood or carpet ect.

Any good installer knows that.

Be safe bigger is better.

Think of an Inverter as an Amplifier. It boosts the power from 12v times 10 to 120v. It draws some current.

posted_image



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John DeRosa (Hotwaterwizard)
Stockton California
When in doubt, try it out !




Posted By: hotwaterwizard
Date Posted: August 12, 2005 at 9:19 AM
posted_image

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John DeRosa (Hotwaterwizard)
Stockton California
When in doubt, try it out !




Posted By: boulderguy
Date Posted: August 12, 2005 at 5:21 PM

I'm a little lost here - how does an inverter draw any current without a load attached to it?  If it does, I've clearly got something to learn.  But if the only load it draws corresponds to the AC item attached to it - it's a computer, not a huge load. 

An average cigarette lighter inverter can put out 4 amps+ of 120v AC.  Average laptop probably needs less than 3 amps of 120v AC (and ironically just converts it right back to DC).  Are you saying that if someone uses this in their accessory port that's probably wired with 16-18g OEM wire they're gonna cook their car? 

I agree the bigger wire is usually better, but only when necessary.  If I'm missing something here please fill me in.





Posted By: hotwaterwizard
Date Posted: August 13, 2005 at 7:08 PM

The inverter is a power supply that works in reverse. It takes 12v and alternates it into pulses. All of this switching and running this electricity thru a transformer and stablizing it at 60hz AC uses some power. Load or no load power is being used to do all of this switching. When something is plugged into it the current does increase.

My fathers Inverter used Tubes in it and what they called a Vibrator to produce the alternating current. That is why it was such a high current draw. A solid state one uses alot less current but it still uses it.

To determine your wire size just look at the fuse they use in the Inverter and use the chart I posted to detremine your wire size for the length of wire you need to power it up at full load. Also make sure the Inverter will be big enough to power the load. If the load is 3 amps you want to use atleast a 6 amp inverter because of voltage spikes and acts of nature.

The Inverter is less expensive than the computer so a larger Inverter would be a wise choice. You could end up frying the computer if the Inverter is under sized.



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John DeRosa (Hotwaterwizard)
Stockton California
When in doubt, try it out !





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