safe to wire pin 30 to pin 86?

I want to cut down the number of wires that need to be routed around the dash so I was thinking that on my relays I need a 12v constant to pin 86 and pin 30.

Would it be safe to just cut a small piece of insulation from the "pin 30 to 12v constant" wire and solder in the end of the pin 86 wire. Pin 30 and 86 would still have a 12v constant and the current draw should be 10amp or below.

This would also lower the number of wires that need to be attached to the 12v constant. Which is about 8 at this point lol.

Thanks in advance!

Yep - you have just described a common 3-terminal horn relay (common +12V with switched +12V to the horn, and #85 grounded via the horn button).

But I would use spade connectors else a relay socket rather than solder the relay terminals.

oldspark wrote:

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Yep - you have just described a common 3-terminal horn relay (common +12V with switched +12V to the horn, and #85 grounded via the horn button).

But I would use spade connectors else a relay socket rather than solder the relay terminals.

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Yes I am using a relay socket so i will be soldering the wires for the pins.

Thanks for the info

btw i forgot to ask ill be using a diode for suppressing the coil voltage spike.

Does it matter if the diode is placed before or after the splice for pins 86 & 30?

Normally its across #85 & #86 (line end to the +12V #86) or "as close as possible" merely to reduce antenna length - ie, less change of inductance etc coupling.

But since "most" of the spike is electrically conducted, near enough is probably good enough. IE - you want it "between" the coil and the other circuits on that circuit (ie - before the alarm, switch, sensitive equipment).
And by "most" I mean "the worst effect" etc... IMO I've given a bad description & explanation! (Maybe others will intercede?)

Don't forget to fuse 30, 86 will be adding at most about 1.5 amps to that load.
I prefer to diode across the coil but I have a question, if 86 is constant what is the load being switched at 85? It has to go to ground through a switch. If that switch is say an alarm aux output rather than a physical 12V switch then wire the diode inline to 85, band away from the relay

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Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.

But that doesn't quench the spike - the spike could then superimpose (travel) on the +12V line.
Hence why spike suppressors (diodes) are placed across the source (in parallel). (As opposed to "blocking" diodes that are inline with the signals - ie, in series.)


But those reverse-biased diodes across #85 & #86 only quench a negative spike. But that is the coil's reaction to having its current removed - it doesn't matter which end is removed/cut/stopped, only the polarity across the coil matters - ie, Kathode = diode line-end towards the +ve end of the coil. (Yes? Or do I have to reconsider long forgotten (read: assumed or known) things? Grrr!!! IE - series blocking does not quench, it merely blocks, so instead of -200V going that way (ground), the other end becomes +200V... (??).)

Never understood it till I got the shock about 40 years ago, I haven't forgotten.
Forget the theory I just use what appears to work.

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Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.

Hmmm - it would stop the shock at the switch end, but reflect it out the other.


But honestly Howard, get with the times - you need to update with more modern experiences.....
I posted the shock I got when checking to see if my manual horn button worked. (Due to the horn-ring bush breaking off, I used fingers to short its wire to ground.)   
That was a few weeks ago. Very modern indeed!

I'd like to say it's nice reinforcing and confirming old lessons....


On 2nd thoughts, stick with older experiences. I'd argue they had better quality anyhow! (Unfortunately for me, freshness is still overriding any thoughts of shock quality. Maybe when I fully recover in a few years...)
Besides, with your modern knowledge and long experience, who the heck am I.....

Hey oldspark,

Sorry I wasn't clear in my post. But yes I will be placing a diode between the wires for pins 85 and 86. My alarm will be sending a negative trigger to the relays to pin 85.

I found a wiring schematic on this site here is the thread

https://www.the12volt.com/installbay/forum_posts.asp~TID~86348~PN~2~TPN~2

But since I am splicing pin 86 into 30 I wanted to know if the diode which crosses from pin 86 to pin 85 needs to be before the splice for pins 86 and 30 or after. But you answered that so I will wire the diode in before my splice.

howard, yes I will be adding a fuse to the wire from 12v constant to pin 30. I think a 15amp fuse should work well in this application. One relay is for the headlights and another is for the sirens and another for my trunk release.

I haven't seen any information about suppressing coil voltage spike so I was just going to wire it based on the diagram in the link I posted above. You need to scroll down to "dualsport's" post to see the diagram.

Thanks for your help everyone

It does not matter where it gets put on the wire.  It can be before 30.  I always solder the diode to the base of 85 and 86.  Place the relay on the edge of a table or bench, set the diode on the relay and bend the legs to the appropriate length, solder the legs to 85 and 86, this leaves plenty room to install the connectors to the terminals of the relay.  It makes a neat install and it is more maintenence free than soldering the diode to a wire that is subject to moving.

i am an idiot wrote:

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It does not matter where it gets put on the wire.  It can be before 30.  I always solder the diode to the base of 85 and 86.  Place the relay on the edge of a table or bench, set the diode on the relay and bend the legs to the appropriate length, solder the legs to 85 and 86, this leaves plenty room to install the connectors to the terminals of the relay.  It makes a neat install and it is more maintenence free than soldering the diode to a wire that is subject to moving.

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I hear ya, but i am using relay sockets which eliminate the chance of me doing this.

Yeah - effectively Idiot means the same - wire direct between the socket pins...

It's a pity an early post Diodes across relay coil doesn't include a simple pic like...

.. but without the RHS resistor and cap.

The diode as shown is the same as a quenching diode.


Maybe the next is better?

The last relay socket I used, you can easily remove the pins from the socket. This should give you access to the bare pin which you can then solder directly to. It is not as "stable" as soldering directly to the relay legs but as a bonus you will have a permanent diode installed for that particular socket.

At least with this method you will have the advantage of the socket holding the pins fairly snug as opposed to attaching the diode to wires only.

It's

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Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.

Sorry too fast for my own good.
Two points:
a) It's
EASY to solder the diode to the relay pins right at the base and then add the socket.
b) Those receptacles are easy to remove using the straight tool from a Snap-On or similar pick set or a thin bladed electrical screwdriver, just inset to the tab, push home the tab and out it comes.
In fact I still have loads of those receptacles and a non -insulated crimping tool.

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Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.

it's even easier to solder the diode in place if you lightly file the terminals on the outside edge with a small file. shape the diode leads like the lower portion of an 'H'...use pliers to give sharp 90 degree bends. place along outer edges then use bend the remaining tail back under each terminal. solder then trim with cutters.
you could always use a cable tie around the relay/socket combo to hold said assembly together.
mark

The diode will not affect the relay socket.  It will still go on easily.

And here I am usually recommending to solder to the socket so that you can substitute relays for testing or replace faulty ones....

Then again, soldering direct to the relay is the ideal and - with spare relays with diodes - the quickest way to replace a faulty diode (if you somehow notice it....!).
But then - make sure you stick to the -ve #85 and +ve #86 convention!! (Diode in the socket or harness doesn't matter - that simply matches the wiring...)

And I don't see that the "insecure" connection between the diode/socket and relay is much of an issue - if the spike gets to the socket, then it will be quenched.
However, I can see the unreliability of sockets. (I stopped using sockets for integrated circuits etc years ago and soldered IC for automotive applications - even they would vibrate or oxidise bad.)


Comment: So many opinions - all valid. IE - diode direct on relay pins is short; on socket or harness is "universal", etc.
But I do like the DIY diode addition - I dislike relays with internal diodes (cost; what if they blow? etc).

As I already said this you are absolutely right Mr.I, this thread is starting to get silly.

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Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.

I was going to solder a diode to the bottom of a relay to show how I do it.  I summoned a relay and a diode from the bay, they brought me a 6 amp diode.  They said we were out of 1 amp devices.  So needless to say, I have no pictures today.

so if i solder the diode to the pins, my socket will not slide all the way on. someone above suggested that i use a zip tie to make sure the socket doesnt fall off.

this will be fine right? even though the pins are not all the way in the socket?

The way I was going to do it is like in this thread linked here

https://www.camaro5.com/forums/showthread.php?p=3237546

it is the first picture of the relay socket in the thread. I found it by luck searching diode relay socket.

If someone has a picture of what this should look like that would be great.

Thanks again

i was looking at the diode i bought right now and i forgot how small the "wires" are in diameter. should be fine. the socket will be about 95% on the pins. i will just wrap it around the pin and solder it.

btw - will the heat from my soldering iron damage anything on the relay?

Not enough, you really need to install this in an epoxy sealed box conforming to IP 68.

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Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.

Place the relay upside down on the edge of a table or bench.  Bend the legs of a 1 amp diode (1n4001)  lay the diode on the relay.  Solder the legs onto the base of the pin.  (Where the pin meets the plastic of the relay housing)  I have never had trouble with or had to worry about the socket going back on the relay.  You may want to use a Dremel tool and remove some plastic from the relay and the socket to make for a diode recessed half way into the relay and the other half will be inside the socket.

New question,

I was trying to figure out what size wire I should use for my 12v constant to my alarm and I noticed inconsistencies between many sources regarding the max current different sizes of wire can handle.

For instance I wanted to use a 16gauge wire for my 12v constant and the 12volt site has this guide:

https://www.the12volt.com/info/recwirsz.asp

And it says that 16 gauge can handle 15amps

But on another page, for example:

https://bcae1.com/wire.htm

it states the max current is 7.5.

Am I missing something? Please help me understand this

Thanks

Why would you need to extend this wire?
These daft questions are really too anal and sooner or later no one's going to answer you, please use some common sense and think it through

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Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.

howie ll wrote:

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Why would you need to extend this wire?
These daft questions are really too anal and sooner or later no one's going to answer you, please use some common sense and think it through

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Firstly, I am sorry to those who feel I am asking unnecessary questions. I only ask because I feel it's important.

I understand to an experienced person who deals with these things all the time it may seem anal, but I am still new to this.

I have made an honest attempt to figure out and research what size wire I need and I cannot get consistent information regarding what size.

I'm not sure how common sense will help with determining the wire size. For example with a powerful amp I cannot just use a small wire. There must be a way to figure out how much current certain size wires can handle.

If I was able to find a consistent answer as to the current diff size wires could handle I wouldn't have asked this question.

I am not extending any wires. Not sure where you got that from??

I need a 12v constant to my alarm. I simply searched which size wire I can use and the max current wires can hold.

Can you help me understand how this is too anal? I thought this would help others in the future.

Maybe you consider it anal because alarms require very little current and any size wire should work. If this is the case then I can understand. But I am just trying to follow things by the book.

If you aren't extending the wire why even ask the question?
Don't you think DEI has researched this more than you are I and have the answers.
For your general interest 16 gauge is perfectly adequate for all alarm wiring except remote start high power (high current) outputs.

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Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.

Try this wire amps and wire gauge-12 volt circuit. It took me two seconds to find this site via Google, just try wire gauges 12volts if the above doesn't get you in
You must do your own homework
Since we use metric here rather than US gauges, I'm guessing that most wiring on DEI product is 22 gauge with the exception of power, lighting and ground which are 18-20.
Over here DEI products have a 15-20 amp rating on the lighting circuit and 5 for the alarm
Don't forget those figures aren't continuous, an alarm draws about 30 milliamps at rest and about 1-15amps when triggered (including siren and lights).
You must do your own homework before asking these generally irrelevant questions.

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Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.

howie ll wrote:

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Try this wire amps and wire gauge-12 volt circuit. It took me two seconds to find this site via Google, just try wire gauges 12volts if the above doesn't get you in
You must do your own homework
Since we use metric here rather than US gauges, I'm guessing that most wiring on DEI product is 22 gauge with the exception of power, lighting and ground which are 18-20.
Over here DEI products have a 15-20 amp rating on the lighting circuit and 5 for the alarm
Don't forget those figures aren't continuous, an alarm draws about 30 milliamps at rest and about 1-15amps when triggered (including siren and lights).
You must do your own homework before asking these generally irrelevant questions.

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I did google wire amps and other information. If you see my post above it has two links I found and am using these as examples. So claiming I haven't attempted to do some homework is nonsense in my opinion.

And you must have missed my point which was that the sources I have found are not consistent as to the max current the wires can hold. My examples show one site stating 15amps and one showing 7.5amps.

So back to part of what I wanted to know was why is it not consistent about the max amps wires can hold. If the reason is to complicated because of some in depth electrical math equations then thats fine but I just thought I would be able to find a simple answer and this is not the case.

BTW thanks I will be picking up some 16awg wire tomorrow from the local hardware store. and I understand what you mean by extending the wire. The 12v constant on the alarm is going to my 520t backup battery and I need a 12v constant source to my 520t. also I need to wire it in the rear of the vehicle for a stealth install.

I still don't understand how this is irrelevant. But I can't argue with the way some people feel. If this was irrelevant I would just run a 22awg wire that needs to handle 10-15amp load.

Your're missing the point! The rear battery won't need a CONSTANT 7.5 amps, it's drawing about 400 milliamps when it's charging.
22AWG is more than adequate. Power loss over cable length is only relevant to high current devices such as amps, headlights, horns, cooling fans and relays will take care of the latter.

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Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.

fair enough