Spade terminals power/voltage rating

Thread Starter

James 26

Joined Mar 26, 2020
10
Hi,

Just a quick question, I have the mains supply lead on a sandwich press and just have a question about suitable terminal connectors.

I only have automotive spade crimp terminals rated at a minimum of 10amps but I am unsure if they have a voltage rating. I know the appliance does not draw any more than 4 amps due to testing with my clamp meter.

I am however unsure about any power or voltage rating of the spade terminals, would I be correct in my thinking if I have terminated them correctly ie. Sufficient surface area at the join and tightly there will be minimal power dissipated at the connection so it shouldn't be an issue ie. P=I^2R
 

Ian0

Joined Aug 7, 2020
9,668
Their voltage rating is the voltage rating of the insulation. If they are uninsulated then there is no voltage rating.
 

MisterBill2

Joined Jan 23, 2018
18,176
There would not be a voltage rating for single terminals, other than possibly there might be a rating for the insulation if they have it. Only the current handling rating matters though, The current rating is applicable only if the terminals are crimped to the specification.
 

MrAl

Joined Jun 17, 2014
11,389
Hi,

Just a quick question, I have the mains supply lead on a sandwich press and just have a question about suitable terminal connectors.

I only have automotive spade crimp terminals rated at a minimum of 10amps but I am unsure if they have a voltage rating. I know the appliance does not draw any more than 4 amps due to testing with my clamp meter.

I am however unsure about any power or voltage rating of the spade terminals, would I be correct in my thinking if I have terminated them correctly ie. Sufficient surface area at the join and tightly there will be minimal power dissipated at the connection so it shouldn't be an issue ie. P=I^2R
Hi,

Anything labeled for automotive use is usually rated for 30v.
There may be exceptions but if they are not rated for what you intend to use them for then its always a risk even though they may appear to work right at first. There could be something about them that you are not aware of until something goes wrong.
 

MrChips

Joined Oct 2, 2009
30,711
Spade terminals are very common in appliances. I wouldn't be too worried about it. Just make sure that you use the correct wire gauge and that it is securely crimped. Do not add solder on the bare conductor.
 

GetDeviceInfo

Joined Jun 7, 2009
2,192
Corrosion is often the downfall of spade connectors. Add strain relief as required. We soldier them for EV applications, and use a anti corrosion grease
 

MisterBill2

Joined Jan 23, 2018
18,176
Max, the downside of those "wonderful" crimp connectors is that they are not field repairable. And the correct crimper is seldom available in an urgent situation. And those 125 amp crimp connector pins are never in stock, anyway.
So for my clients I always soldered the crimp pins onto the wires. Then I could remove the pin when the wire broke, unsolder the broken stub of wire, Solder that pin, or a replacement on, and have the cable assembly repaired in just a few minutes, instead of three days for a super-hot rush replacement cable. My client was very pleased and even more amazed that it could be done like that.
 

MaxHeadRoom

Joined Jul 18, 2013
28,618
Max, the downside of those "wonderful" crimp connectors is that they are not field repairable.
You buy the right one, you don't need to worry.
I swear by Weidmuller, OK they are $$$'s, But when used for your professional use it is unbeatable.
They will out wear me.
Power carrying cables are not allowed to use solder pocketed lugs for a reason.
 

MisterBill2

Joined Jan 23, 2018
18,176
You buy the right one, you don't need to worry.
I swear by Weidmuller, OK they are $$$'s, But when used for your professional use it is unbeatable.
They will out wear me.
Power carrying cables are not allowed to use solder pocketed lugs for a reason.
Wires can be damaged no matter how good the terminals are. Not pulled out of the terminal, but broken or sheared. And I have re-installed a 28 pin connector on a 28 conductor cable that was slapped in two by a whipping high pressure hydraulic line that had broken. Fortunately nobody was injured. Quite high pressure in that one inch line.
 

MrAl

Joined Jun 17, 2014
11,389
Max, the downside of those "wonderful" crimp connectors is that they are not field repairable. And the correct crimper is seldom available in an urgent situation. And those 125 amp crimp connector pins are never in stock, anyway.
So for my clients I always soldered the crimp pins onto the wires. Then I could remove the pin when the wire broke, unsolder the broken stub of wire, Solder that pin, or a replacement on, and have the cable assembly repaired in just a few minutes, instead of three days for a super-hot rush replacement cable. My client was very pleased and even more amazed that it could be done like that.
Hi,

One of the differences between a crimp and a solder is the crimp allows the wire to flex a bit more which reduces breakage if it has to move or vibrate.
The solder forms a somewhat sharp edge (although not too too sharp) that can cause the wire to start to fray little by little if it has to flex near the solder joint or vibrate a lot.
I like solder joints myself, but in my car, I use crimps because my 12v soldering iron is not very powerful.
 

MisterBill2

Joined Jan 23, 2018
18,176
Solder in a connector with support back from the pin does not allow much flexing or vibration win the shell. Possibly in aircraft and rockets , but those are often encapsulated after assembly.
Also, it is entirely possible to not solder all the way to the outer end of the lug barrel.
 

Ian0

Joined Aug 7, 2020
9,668
Hi,

One of the differences between a crimp and a solder is the crimp allows the wire to flex a bit more which reduces breakage if it has to move or vibrate.
The solder forms a somewhat sharp edge (although not too too sharp) that can cause the wire to start to fray little by little if it has to flex near the solder joint or vibrate a lot.
I like solder joints myself, but in my car, I use crimps because my 12v soldering iron is not very powerful.
The metallurgy is also important. When soldering copper wire an brittle alloy is formed around the area when the soldered part ends. Earopean standards require that any soldered wire is also mechanically supported by another means.
A good crimp is best, but a crimp with the wrong size lug, the wrong sort of cable or a poor crimp tool is asking for trouble.
 

MrAl

Joined Jun 17, 2014
11,389
The metallurgy is also important. When soldering copper wire an brittle alloy is formed around the area when the soldered part ends. Earopean standards require that any soldered wire is also mechanically supported by another means.
A good crimp is best, but a crimp with the wrong size lug, the wrong sort of cable or a poor crimp tool is asking for trouble.
Hi,

Yeah, so many pitfalls in both methods this is an area where you really have to understand what is going on.
I recently purchased a new crimper too, and was a little bothered by how much it squeezes the plastic part of the lug. If i need to, i also use a piece of heat shrink over the wire before installing the lug terminal, then slide it over the plastic part and heat shrink it. Makes a nice higher voltage insulation.
 

MrAl

Joined Jun 17, 2014
11,389
Solder in a connector with support back from the pin does not allow much flexing or vibration win the shell. Possibly in aircraft and rockets , but those are often encapsulated after assembly.
Also, it is entirely possible to not solder all the way to the outer end of the lug barrel.
Hi,

Yes i guess we are talking an extra wire support besides the solder alone.
A good example of this is when soldering an alligator clip to the end of a test lead. There is also a crimp that has to be made, and that crimps to the insulation over the wire, not the copper itself, so it provides a little more support before the stress to the copper part of the wire encased by the solder. The insulation acts as a micro movement damper as the wire bends outside of the alligator clip end.
I have also experimented with an extra solid wire that extends out the back of the alligator clip where the wire with insulation wraps around before the copper part goes into the clip end and is soldered. That handles a LOT of stress but it's a little difficult to implement on small alligator clips. I can envision custom made alligator clips that almost never have the wire break off of the back end of the clip. In fact, i can envision special lug terminals made like this too although the big wire gauges would look strange with an extra loop of wire at the end of the terminal, and would add bulk to the finished crimp.
 
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