30a switch, relay needed?
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=121657
Printed Date: May 04, 2024 at 12:49 PM
Topic: 30a switch, relay needed?
Posted By: jettagli03
Subject: 30a switch, relay needed?
Date Posted: May 03, 2010 at 2:58 PM
I am putting my two gauges in my car on a switch. If they both combined use less than 30A, which I'm sure they do, do I need to use a relay if the switch I have is rated at 30A?
Thanks!
Replies:
Posted By: KPierson
Date Posted: May 03, 2010 at 3:58 PM
No, you wouldn't. Just make sure your wire is large enough and is fused properly.
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Kevin Pierson
Posted By: i am an idiot
Date Posted: May 03, 2010 at 5:58 PM
What kind of gauges do you have that the 2 may pull 30 amps of current to operate?
Posted By: oldspark
Date Posted: May 03, 2010 at 9:29 PM
Ditto! (Not an ammeter surely!!!)
And why use a relay of the switch is rated for 30A??!!
Gauges are unlikely to draw more than 1 Amp if that.
And hence there is no need for a relay - the normal "metering" circuit is usually fine. (One exception - voltmeters - they should be measuring battery voltage - ie, direct from battery + & - terminals.)
Posted By: jettagli03
Date Posted: May 04, 2010 at 12:22 AM
I was not home to see what they pull for amperage (1.3A per and the are AEM digitals - wideband o2 and boost) I just wanted to make sure I didn't need a relay as I'm new to using relays and switches.
Thanks for your help!
Posted By: howie ll
Date Posted: May 04, 2010 at 4:51 PM
Doubt if they pull more than 500milliamps combined + illumination on a separate circuit. I can't for the life of me see why you need to switch gauges.
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