Question about 12 volt auto relays

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Can the contacts of a 12 volt 30 amp auto relay handle 120 volts at about an amp of AC current?
Couldn't find a car group that was still active.
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snipped-for-privacy@invalid.com expressed precisely :

NO NO you would be exceding the insulation ratings by 10 times.
The contacts can certainly handle 1 amp AC but the higher voltage is way outside the designed safety limits. 8-o
--
John G Sydney.

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That's pretty much what this page says.
http://www.the12volt.com/installbay/forum_posts.asp?tid 2645
Thanks for answering.
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On Sun, 19 Apr 2015 01:33:11 -0500, snipped-for-privacy@invalid.com wrote:

I finally found something. According to this page the answer would seem to be no.
http://www.the12volt.com/installbay/forum_posts.asp?tid 2645
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On 04/19/2015 02:17 AM, snipped-for-privacy@invalid.com wrote:

The only way to absolutely know is to look at the relay and observe the manufacturer's marked specifications. Automotive relays typically have their contacts rated at 14V DC.
If the contact ratings are marked 115v AC/DC then it would be OK to use.
Bottom line is that unless it's specifically marked for 115v ac or higher , due to safety concerns I would not use the relay.
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snipped-for-privacy@invalid.com wrote:

Smoke and pow! relay coil is gone.
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Why not just get a proper relay and use it. I hope that the auto relay you want to use is not a starter relay. The problem with them is most of them have the coil and contact connected internally as the battery input. This would present a problem with the coil voltage inseparable from the contact voltage.
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On Sun, 19 Apr 2015 20:53:03 -0400, "EXT"

the fact he said it was a "30 amp" relay pretty well rules out 85-300 amp starter solenoids, doncha think??
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On 4/19/2015 2:33 AM, snipped-for-privacy@invalid.com wrote:

Very possibly yes. But, the insullation isn't rated for 120 VAC, so it may be unsafe.
- . Christopher A. Young learn more about Jesus . www.lds.org . .
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On Sunday, April 19, 2015 at 1:33:24 AM UTC-5, snipped-for-privacy@invalid.com wrote:

My experience says yes...going the other way, 120 rated points can't handle 12 volts at the typical automotive use amperage. The wiring can also handle 120. (although not rated for it).
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On Sunday, April 19, 2015 at 8:34:25 AM UTC-4, bob_villa wrote:

Your experience is wrong. It's not just voltage and current that are involved. There is the fundamental difference between AC and DC. With AC, the current reduces to zero on each cycle. Unless the relay is designed to allow for that, the contacts can release. That's why there are AC relays, DC relays, and some that will do either.
I've never seen an auto relay rated for AC or 120V.
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Actually, twice each cycle...
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On 4/19/2015 9:02 AM, danny burstein wrote:

Here's your sine!
(very big grin, my friend.)
- . Christopher A. Young learn more about Jesus . www.lds.org . .
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On Sunday, April 19, 2015 at 7:58:29 AM UTC-5, trader_4 wrote:

Thanks for the lesson...he was asking about contacts and not the coils of the relays. And I never said they were rated for it...learn to read or not comment.
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On Sunday, April 19, 2015 at 9:05:06 AM UTC-4, bob_villa wrote:

While you're right that he said contacts and didn't say what he was going to drive the coil with, you still don't know what you're talking about, because you implied it's OK to do. As for the contacts, what's up with this?:
"120 rated points can't handle 12 volts at the typical automotive use amperage"
There is no typical automotive use amperage or 120V amperage. There is only what the relay is designed and rated for. If you have a relay with 120V 10A contacts, the contacts could handle 10A at 12V.
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On Sunday, April 19, 2015 at 8:28:29 AM UTC-5, trader_4 wrote:

This, of course, is not true for the reason YOU gave before...DC is NOT the same as AC. The AC 10A rated contacts would burn-up using it for DC. Your area of expertise is clearly not in evidence here.
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On Sunday, April 19, 2015 at 9:37:59 AM UTC-4, bob_villa wrote:

Really, burn up? With *any* DC voltage or current? I never said relay contacts rated for 10A, 120VAC could handle 10A, 120V DC. When you have contacts rated for both, the DC amperage rating will be substantially less at the *same voltage*. But were talking about going from 120V to 12V at the same time, a factor of 10X, in which case, the contacts rated for 120V, 10A, can probably handle the 10 amps at just 12V. And even more to the point, he's actually going from 120V to 12 volts and from 30A to just 1 amp.
But the right answer is that the relay should be rated for the application. And it would probably be more productive if he told us what he's really trying to do.
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On Sunday, April 19, 2015 at 9:18:28 AM UTC-5, trader_4 wrote:

What IS the point in even responding to your drivel...you add more words, beleaguer the point and say the same thing...never admitting you're wrong. Stick it!
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On Sunday, April 19, 2015 at 10:55:35 AM UTC-4, bob_villa wrote:

I guess the point would be to clarify WTF you're talking about. Typically switching contacts rate for AC can also be use with DC at derated voltage and/or current. So, contacts rated for 120V AC, 10A, will probably be OK at 12V DC, 10A.
Here's an example of a common relay data sheet that shows exactly that:
http://www.digikey.com/product-detail/en/MKS3PN5AC24/MKS3PN-5%2520AC24-ND/2663288?WT.z_cid=ref_ihs_dkc_buynow
Note that the contacts are rated for 10A, 250V AC or 30V DC, it's one example of a relay that does just what I said. It would be fine at 12V and 10A.
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trader_4 wrote:

There is mobile electronics, 12V DC specific relays every where.
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