Electric component ratings AC vs. DC

[Functional Artist]

So, (in your opinion/hypothetically) how many amps should an average "house hold" C-14 receptacle with a 250VAC 10A rating be able to handle @ 48VDC?

...how about @ 60VDC?

Not a "limb" you (or anyone) is willing to venture out on?
...totally understandable.

I know this stuff is NOT in the book
...but, there's has to be a range where "it's gotta be safe" to run DC voltage thru a conductor
(it's just a conductor)
…& (up to) a certain amount of Amps.
(even if they only have an AC voltage rating listed)

I guess were gonna have to do some testin'.
...to know for sure

 

[sikbrik]

To quote the Beavis of my youth, "yeah, fire...fire! Fire! Hehehehehehehe"

Testing is certainly in order, maybe with high speed cameras involved

But seriously, I tend to agree that there are likely components which are identical but rated only for ac or dc, so measurements and tests could identify those parts and expand the pool of locally available components.

 

[Functional Artist]

I tend to agree that there are likely components which are identical but rated only for ac or dc, so measurements and tests could identify those parts and expand the pool of locally available components.

Yes, "expand the pool of locally available components"
...that's a good way of putting it.

I wouldn't use the term "identical" though
...more like suitable, adequate or "meets the criteria"
...but, also for a "specific situation" (very important)

Let me say that again, "for a specific situation"

* When venturing "out side of the box", it's best to analyze everything closely
...or think thru every single aspect of a project (or circuit)

Then, if everything (you can think of) is accounted for
...& no RED flags (or Sid ) have "popped up" sayin "I don't think so pal"

...it's time for testin'.

 

[Functional Artist]

Testing...
I guess the procedure to test a receptacle/power coupler "conductor" would be to simply connect an appropriate voltage power source & increase the amperage (incrementally) until it fails.
...while monitoring & recording data.

What do I anticipate will fail?
Well, I can't see the "conductors" themselves failing
...so, I would have to say, melting of the (plastic) housing itself.

But, I'm not really interested in product testing, per se

I just want info on if these power couplers can "safely" withstand ELV voltages (up to 72VDC) @ 2.5A

As I've said, I've used them to charge my 48V karts many times & the receptacles never ever got hot or even a little warm.
...so, I'm pretty confident of using them @ 48VD & 2.5A

Then, I'll just have to give 'em a try @ 60VDC @ 2.5A & monitor it closely.

 

[Functional Artist]

Test?
What should we be testing?
...just the receptacle it self?
...the receptacle with fuse folder
...or the (3) way combo unit (receptacle, fuse holder & switch)

Lets break 'em down

Receptacle
The (AC only rated) C-14 receptacles were are discussing are female type receptacle that have (3) "blade" type conductors mounted in a (usually some kind of plastic) housing.
The "blades" protruding from the front side are in a house shaped enclosure & are configured to hold & support a mating C-13 plug & also align the "blades" so they can make contact with the contacts in a C-13 plug.
…& then, on the back side there are (3) spade type terminals (sometimes soldering lugs) protruding for connecting the wires (more conductors) to. ...& that's all there is to it.

Fuse Holder
A fuse holder is basically just a receptacle (conductor) with specially shaped contacts, that's also mounted into a (usually) plastic housing.
...it's just is designed to align, make contact with & hold/support a certain shaped fuse. (fuses AC vs. DC is another discussion)

So, since they're both conductors, they should have the same "ratings" ACV or DCV.

As a way to kinda confirm this, just look on the back of our example (3) way combo C-14 receptacle with fuse holder & switch.

Yup!, they are both rated 10A 250V~
...so, now, lets discuss the switch section

Switch
A switch is also just basically a conductor, when contact is maintained.
...but, as we have discussed, it is rated to the amount of flowing current it can safely "break" repeatedly with out any damage. (This switch is rated 250V~ 6.3A 2.5W)


But, this situation may be a little different.

In "this specific" situation, the switch isn't required to "actually" break the flowing current.

What do you mean?
What I mean, is the switches job/duty (in this situation) would only be to "switch" the C-14 receptacle off, when not in use.
...thus eliminating the open terminal issue.

* IMO the receptacle, fuse holder & switch should work fine in this situation
...but, for added safety, & to help make it "stupid proof" it would probably be best to find, install & use a properly rated switch with this receptacle.

...thoughts?

 

[itsid]

Not a "limb" you (or anyone) is willing to venture out on?
...totally understandable.

You still DON'T UNDERSTAND!
the C-14 receptacle handles the full rated amperage at every voltage up to 250V (ac or dc doesn't matter at all in case of connectors!)
since it's not a switch it nearly doesn't matter what voltage you have unless you reach the thermal capacity of the part.
(means.. it's made of metal.. it has a resistance.. that causes loss..which is converted to heat .. at one point it heats up too much.. that's the only limit)

Yes there is a voltage limit (you're unlikely to meet) at which you will arc through the insulation,(remember it's tested to 1100Volts DC.. maybe failtest, maybe not *shrugs*)

it's the SWITCH that causes troubles!

Also.. please do not mess up bigger > and smaller < arrows
>75V is voltages from 75.1V and BIGGER,
<60V are voltages up to 59.9V

Always assume a variable (say X) on the other end of the larger/smaller sign.

5V< X <7V are voltages between 5 and 7 (exclusively btw)
5V <= X >= 7V are voltages between 5 and 7 INCLUSIVELY

one is a typo, two consecutive wrong uses are a pattern

'sid

 

[Functional Artist]

You still DON'T UNDERSTAND!
the C-14 receptacle handles the full rated amperage at every voltage up to 250V (ac or dc doesn't matter at all in case of connectors!)
since it's not a switch it nearly doesn't matter what voltage you have unless you reach the thermal capacity of the part.
(means.. it's made of metal.. it has a resistance.. that causes loss..which is converted to heat .. at one point it heats up too much.. that's the only limit)

Yes there is a voltage limit (you're unlikely to meet) at which you will arc through the insulation,(remember it's tested to 1100Volts DC.. maybe failtest, maybe not *shrugs*)

it's the SWITCH that causes troubles!

Also.. please do not mess up bigger > and smaller < arrows
>75V is voltages from 75.1V and BIGGER,
<60V are voltages up to 59.9V

Always assume a variable (say X) on the other end of the larger/smaller sign.

5V< X <7V are voltages between 5 and 7 (exclusively btw)
5V <= X >= 7V are voltages between 5 and 7 INCLUSIVELY

one is a typo, two consecutive wrong uses are a pattern

'sid

Now, I think were getting somewhere

Yes, AC or DC doesn't matter for connectors/conductors (that's kinda what I've been sayin')
...but, NOT switches, "switches are a whole 'nother animal", apples & oranges etc.

So to be clear, ALL connectors like the C-14 receptacles (pictured below) "should" be able to handle up to 250 volts AC or DC?
...NOT just the DC rated TDK C-14 example that you mentioned earlier?
https://en.tdk.eu/inf/30/db/emc_2014/B84771.pdf

Also, if I understand you correctly, the metal that you refer to:
"(means.. it's made of metal.. it has a resistance.. that causes loss..which is converted to heat .. at one point it heats up too much.. that's the only limit)"
...is the protruding conductors that "actually" make contact, or as I referred to them earlier as "blades"
...& "if" they heat up "too much", the plastic housing holding them usually fails.

Thanks for bringing the (> & <) to my attention
...some how, I had it in my head that > meant (up to)
...kinda like (>75VDC = less than 75VDC)

* I fixed 'em & I'll try to remember & get 'er right next time.

 

[itsid]

NO, that is a Switch, that 'by incident' shares it's housing with a C-14 connector and a fuse

'sid

 

[Functional Artist]

NO, that is a Switch, that 'by incident' shares it's housing with a C-14 connector and a fuse

'sid

NOT the switch part

Yes, I understand & you have made it very clear that switches are a whole 'nother animal.

That pic as just an example of a standard (ACV rated) C-14 power cord connector, fuse holder & switch holder.
…& I now know that, if used for our DCV purposes, (& to be used as a switch) the switch would have to be replaced with an appropriate DCV rated switch. (ex: 250VDC 10A)


First, I would like to make it very clear that we are (now) discussing "pretty much" ALL standard IEC 320 C-14 (ACV rated) power receptacles (like pictured below)
…& that they should be safe to use on most ELV charging circuits (up to 75VDC & up to ~10A).

NOT just the (250VDC 10A) TDK IEC inlet filters (tested to 1,100 VDC)

I just want to be sure because here, you say:
"Yes there is a voltage limit (you're unlikely to meet) at which you will arc through the insulation,(remember it's tested to 1100Volts DC.. maybe failtest, maybe not *shrugs*)"

But, there you must be referring to the TDK receptacles because the "other" C-14 receptacles (like pictured below) are only used for ACV applications & as such they don't have any DCV ratings. ...Correct?

How about the fuse holder? (with appropriate DCV rated fuse)
...it's just a connector/conductor too.

 

[itsid]

Kevin, I know what information you are after.
You will not get that!

If a part is NOT rated or not even tested for a specific DC voltage and/or amperage,
you cannot just assume things, not even if the same manufacturer (like TDK in this case)
offers another part that looks the same or smells the same.

One can make an educated guess, based on experience and datasheets, but in the end,
you cannot rely on that either.
buy two, test one to failure, and rate the second according to made observation.
You still won't have any guarantee, but the closest you get to a good assumption.

Manufacturers do not test one part, they test thousands of parts and base their rating on that, you can't do that reasonably in your home shop, so a single test and a good enough margin will have to do.

And keep in mind that there are many different models of the very same part (covered in that very same datasheet) some with lower some with higher ratings.

I won't say anything about that switch you now posted the third time;
I can't .. I don't have one to test, I don't intent to buy one for testing.

And frankly as long as you don't even know what voltages and currents you are actually 'switching' or 'fusing' with it, there is no point to even think about it.

Chances are you switch 5V 150-200mA and keep wondering if that switch would hold 10A @ 60VDC
And that's exhausting ..
it's like constantly wondering if the tyres on your kart would hold up to speeds above 130mph
when your kart can only go 30mph...
Do as you like, but it gets boring pretty quick for everyone else.

TEST what needs to be switched, fused or connected for voltage and max amperage,
then buy matching parts.. it's not difficult really..
and all this ac/dc "assumptions" are utterly pointless,
for a handfull of parts it simply doesn't matter enough to make a difference (for homegamers)
and for others there is no way to derive any safe (yet unknown) number from any known one.

Not rated for DC voltages.. when in doubt, skip that part and move on.. look elsewhere.

'sid

 

[Functional Artist]

Kevin, I know what information you are after.
You will not get that!

If a part is NOT rated or not even tested for a specific DC voltage and/or amperage,
you cannot just assume things, not even if the same manufacturer (like TDK in this case)
offers another part that looks the same or smells the same.

One can make an educated guess, based on experience and datasheets, but in the end,
you cannot rely on that either.
buy two, test one to failure, and rate the second according to made observation.
You still won't have any guarantee, but the closest you get to a good assumption.

Manufacturers do not test one part, they test thousands of parts and base their rating on that, you can't do that reasonably in your home shop, so a single test and a good enough margin will have to do.

And keep in mind that there are many different models of the very same part (covered in that very same datasheet) some with lower some with higher ratings.

I won't say anything about that switch you now posted the third time;
I can't .. I don't have one to test, I don't intent to buy one for testing.

And frankly as long as you don't even know what voltages and currents you are actually 'switching' or 'fusing' with it, there is no point to even think about it.

Chances are you switch 5V 150-200mA and keep wondering if that switch would hold 10A @ 60VDC
And that's exhausting ..
it's like constantly wondering if the tyres on your kart would hold up to speeds above 130mph
when your kart can only go 30mph...
Do as you like, but it gets boring pretty quick for everyone else.

TEST what needs to be switched, fused or connected for voltage and max amperage,
then buy matching parts.. it's not difficult really..
and all this ac/dc "assumptions" are utterly pointless,
for a handfull of parts it simply doesn't matter enough to make a difference (for homegamers)
and for others there is no way to derive any safe (yet unknown) number from any known one.

Not rated for DC voltages.. when in doubt, skip that part and move on.. look elsewhere.

'sid

I thought we were getting somewhere

Well, I'ma gonna go at it another way

Look at the wires & connectors on a 24V YK31 speed controller. (see pics below)
The wires for the "power circuits" are (~10g.) copper strand wire
...the wires for the signal, control & charging circuits are all (~18g.) copper strand wire
…& the connectors are just a plastic housing with contacts/terminals made of copper or maybe brass.


Now, lets look at the wires & connectors on the speed controller for the Boma 60V 1,800W motor.

Notice that wires & connectors look to be the same on both the (24VDC & 60VDC) speed controllers.

Does this indicate that the same wires & connectors that meet the requirements for a 24DC system, must meet the requirements for a 60VDC system?

* Maybe to help confirm, what are the specs for
...10g. & 18g. wires?
...or them plastic connectors?

** Those specs should meet or exceed the requirements for both 24VDC & 72VDC systems.


Now, lets look at the AC input cord & DC output cord on this 60V battery charger.

Notice that they use the exact same cord/wire, with the exact same numbers (CCC A007700 60227 IEC 2x0.5mm(2) 300/300V) for both the 110V AC input plug & also for the 60VDC output plug.
(sorry pic quality is awful)
https://webstore.iec.ch/preview/info_iec60227-4{ed2.1}en_d.pdf

Does this indicate that the same cord/wires that meet the requirements for a 110V AC system, must meet the requirements for a 60VDC system?


Why am I doing all of this AC ratings vs. DC ratings research?

Most average folks don't even know there are big differences between the ratings for AC components & DC components. (I didn't)

There are thousands of these small (24VDC - 72VDC) battery chargers available & they come with a variety of different DC output plugs. The (3) pin XLR connectors seem to be popular on electric scooters but, there are also many chargers available with the C-13 for a DC output plug.


So, if the "average diy'er purchases one of these chargers & finds that it did not come with a mating receptacle? (like I did) & (none of them do)
...then, how do they connect it, to "charge" the battery pack on their e-bike, kart etc.?

Most would look around, find & buy a mating component & run with it. (like I did)


So, I wanted to try-n-figure or research to see if it seemed reasonable to assume, that most of "your average" connectors/conductors (even if they don't have an "official" DC rating) can handle/carry up to ~3A @ up to 72VDC? (ELV standards)

For this discussion on charge port/receptacles our "targets" have been
...max voltage (72VDC) & max amp (~3A)

Sorry, I'm kinda CDO
...it's like OCD
...but, with all of the letters in alphabetical order
AS THEY SHOULD BE

 

[Functional Artist]

Warning; do not use a c-14 receptacle as a dc input plug

It has been brought to my attention that using (ANY) C-14 connector, as a DC input receptacle, to charge a battery pack is a catastrophe just "waiting to happen".

NOT because of what it doesn't have (an "actual" DC rating)
...but, because of what it is (it's an AC power cord receptacle)

The C-13 is usually used for connecting AC power cords to home appliances & the C-14 is the receptacle that's usually mounted to the appliance for connecting a power cord.

As such, if a C-14 receptacle is connected to a battery pack & used as a charge port, it presents a HUGE safety risk.

WHY?

What could/would happen if someone just connected an AC power cord DIRECTLY to the C-14 receptacle?
(skipping the battery charger)
...it could/would apply 110VAC DIRECTLY to the 60VDC battery pack (& KaBoom!)

Hopefully the fuse (if one was even used) would "pop" & save the day
...but, who knows?

So, I don't understand why there are so many companies even offering a battery charger with a C-13 DC output plug.
...it's an accident just waiting to happen (& maybe a lawsuit)

I do know (IMO) IT'S NOT A WELL THOUGHT OUT PLAN
…& I won't be using them anymore

 

[Functional Artist]

Safer Alternatives

A fact like that will stop me "dead in my tracks"
Moving on
XT type connectors were suggested to me as a "safer alternative" to use as a charge port for connecting a battery charger to a battery pack.

Hmmm
...yup, I did some research

It seems that XT connectors are used by RC (remote control) enthusiasts.
They use them for connecting battery packs to powering the vehicle
...& also for connecting the battery chargers to recharge 'em too.

It looks like they come in (3) versions the XT30, XT 60 & XT 90 all have gold plated spring connectors (contacts) & the housings are made of high-temp Nylon.

They all have a 250+ AC/DC voltage rating, the main difference is in the contact size & by extension the amp ratings
...the XT30's have 2mm contacts & are rated for up to 35A (constant)
...the XT60's have 3.5mm contacts & are rated for up to 65A (constant)
…& the XT 90's have 4.5mm contacts & are rated up to 90A (constant)
https://hobbyking.com/en_us/nylon-xt60-connectors-male-female-5-pairs-genuine.html


While doing research I also came across these Molex connectors.
https://www.molex.com/molex/products/datasheet.jsp?part=active/1501761020_CRIMP_HOUSINGS.xml

The "EconoLatch" type are rated 250V AC/DC & up to 12A (depending on the wire size used)
...16AWG = 11.5A
...18AWG = 8.5A
...20AWG = 7.5A
...22AWG = 6.5A
https://www.molex.com/pdm_docs/ps/1501760001-PS-000.pdf

Both of these types are properly DC rated @ way more than enough to easily exceed our "specified operating parameters"
...& should work well for "safely" connecting most of our ELV (up to 72VDC) battery chargers.

 

[Functional Artist]

Kevin, I know what information you are after.
You will not get that!

If a part is NOT rated or not even tested for a specific DC voltage and/or amperage,
you cannot just assume things, not even if the same manufacturer (like TDK in this case)
offers another part that looks the same or smells the same.

One can make an educated guess, based on experience and datasheets, but in the end,
you cannot rely on that either.
buy two, test one to failure, and rate the second according to made observation.
You still won't have any guarantee, but the closest you get to a good assumption.

Manufacturers do not test one part, they test thousands of parts and base their rating on that, you can't do that reasonably in your home shop, so a single test and a good enough margin will have to do.

And keep in mind that there are many different models of the very same part (covered in that very same datasheet) some with lower some with higher ratings.

I won't say anything about that switch you now posted the third time;
I can't .. I don't have one to test, I don't intent to buy one for testing.

And frankly as long as you don't even know what voltages and currents you are actually 'switching' or 'fusing' with it, there is no point to even think about it.

Chances are you switch 5V 150-200mA and keep wondering if that switch would hold 10A @ 60VDC
And that's exhausting ..
it's like constantly wondering if the tyres on your kart would hold up to speeds above 130mph
when your kart can only go 30mph...
Do as you like, but it gets boring pretty quick for everyone else.

TEST what needs to be switched, fused or connected for voltage and max amperage,
then buy matching parts.. it's not difficult really..
and all this ac/dc "assumptions" are utterly pointless,
for a handfull of parts it simply doesn't matter enough to make a difference (for homegamers)
and for others there is no way to derive any safe (yet unknown) number from any known one.

Not rated for DC voltages.. when in doubt, skip that part and move on.. look elsewhere.

'sid

I understand what your sayin'
...but, when re-purposing stuff (or dealing with many Chinese components) you don't always have the luxury of ratings or data sheets.

I re-purpose stuff (& use Chinese made components) daily
...sometimes twice in the same day.

If ya think about it, everything has some type of "common" standards.
…& if an items minimum standards seem to meet or exceed an alternative uses maximum requirements...

Kinda like a paint bucket can be re-purposed, to hold most any liquid (& many solids too)
or
I don't need to know exactly what a brick weighs, to use it to hold down the corner of a tarp.
…but, if I under estimate & the tarp just slides out from under the brick. (nuthin' catches on fire- usually)


* I also understand that when dealing with electrical current & there's a lot more technical issues & variables to keep in mind
…& if things go wrong, they can go VERY wrong VERY quickly.

But, there have to be some kinda basic "signs" or indicators that we can use to our advantage.

 

[Functional Artist]

Indicators

Conductor
Remember, a conductor is simply most anything that conducts electricity.
(a wire, crimp-on terminal, the contacts (in a receptacle or switch), a piece of metal etc.)

Voltage
Most wires (conductors) are rated 300V & most wire ratings don't mention (AC or DC)
...so, the type of current must not matter. (up to a certain point)
…& by extension, I would think that this is also true for most conductors, contacts etc.

So, as far as voltage goes, it looks like most any wires, receptacles etc., should be able to be used in our (up tp 60VDC karts)
...because their ratings easily exceed the voltage requirements of our ELV (extra low voltage/up to 75VDC) systems.

Amperage
So then, it's the amperage "variable" that we need to concentrate on.

The amp requirement of a specific circuit dictates the wire size (20g, 16g. 12g. etc.), the size of fuse/circuit breaker (10A, 40A, 100A etc.), the switches used & also the size of any other conductors (wire terminals, receptacles etc.) that are needed.

Example:
1.) XT connectors
...if they have 2mm contacts, they are rated for up to 35A (constant)
...if they have 3.5mm contacts, they are rated for up to 65A (constant)
…& if they have 4.5mm contacts they are rated for up to 90A (constant)

2.) Molex connectors
...if used with 22AWG wire they are rated for up to 6.5A
...if used with 20AWG wire they are rated for up to 7.5A
...if used with 18AWG wire they are rated for up to 8.5A
…& if used with 16AWG wire they are rated for up to 11.5A

3.) Namz connectors (like used on these MY1020 motors & YK31 speed controllers) (as seen in pics below)
...the smaller ones with ~2mm (~1/8") contacts, are usually used for all of the "small power" control & signal circuits like the throttle, On/Off circuit,
…& the larger ones with ~4.5mm (~1/4") contacts are used for the "big power" power circuits like for the batter & motor.

WPI Work Piece Indicator
These indicators give us a lot of valuable info, on what size contacts & wire is used by other manufacturers to handle different types of loads (signal or power) & at what amperages.
...kinda like the WPI concept

IMO, if we compare this info & these indicators, to the info & indicators that we can find on other components then, we should/may be able to get an "good/educated" idea as to what they can/may be able to handle.

* Definitely NOT the whole picture
...but, some more pieces to the puzzle

 

[Functional Artist]

DC connectors & standards

DC Connector
"A DC connector (or DC plug) is an electrical connector for supplying direct current (DC) power.

Compared to domestic AC power plugs and sockets, DC connectors have many more standard types that are not interchangeable. The dimensions and arrangement of DC connectors can be chosen to prevent accidental interconnection of incompatible sources and loads. Types vary from small coaxial connectors used to power portable electronic devices from AC adapters, to connectors used for automotive accessories and for battery packs in portable equipment."

It seems like this means that it's best to choose & use specific DC power connectors, for specific voltages, to prevent accidental interconnection of incompatible voltages.

Like, only using XLR connectors for 48VDC systems & Molex connectors for 60VDC systems.
This way it is not possible for a 60V battery charger to be connected to a 48V battery pack.

IEC 60906-3:1994
"The International Electrotechnical Commission (IEC) has produced a standard for a system of 2-pin plugs and socket-outlets for household and similar purposes in fixed and portable applications, either indoors or outdoors. Safety extra-low voltage (SELV) plugs and socket-outlets carry up to 16 amperes, and have eight keying possibilities, to indicate 6, 12, 24, or 48 volts, AC or DC."

I knew there had to be some kind of standards. (Notice it says AC or DC)
...but, this is the standard for SELV (Safety extra-low voltage) (up to 48VDC) plugs/sockets & we need ELV (extra low voltage) standards. (up to 75VDC)

XLR Connector
"In the broadcast, film and television industries, the 4-pin XLR4 connector is the standard for 12 V power. The connectors are wired pin 1 negative, pin 4 positive. Often pins 1 and 2 will be negative, 3 and 4 positive for a higher current rating. Female connectors are used as supply and male connectors are used on loads.

The readily available XLR3 is also used by some manufacturers as power supply plugs despite their being a well-accepted standard for other purposes.

Molex connector
The connector design most commonly called a Molex connector has frequently been used to supply DC power, most frequently on personal computers."
https://en.wikipedia.org/wiki/DC_connector

I think I'm gonna designate & use the XLR style connectors on all of my 48V battery chargers
...& the (2 pin) Molex style connectors for all of my 60V battery chargers.

This way there is NO WAY me, my kids or anyone could ever connect the wrong battery charger to the wrong kart.

 

[Functional Artist]

While doin' research I came across this:
https://www.youtube.com/watch?v=XDf2nhfxVzg

That tongue test "killed me"
...I think I might have hurt myself laughing

 

[Functional Artist]

Electric arc

Electric arc
"An electric arc, or arc discharge, is an electrical breakdown of a gas that produces an ongoing electrical discharge. The current through a normally nonconductive medium such as air produces a plasma; the plasma may produce visible light. An arc discharge is characterized by a lower voltage than a glow discharge and relies on thermionic emission of electrons from the electrodes supporting the arc. An archaic term is voltaic arc, as used in the phrase "voltaic arc lamp".

"The first continuous arc was discovered independently in 1802 and described in 1803 as a "special fluid with electrical properties", by Vasily V. Petrov, a Russian scientist experimenting with a copper-zinc battery consisting of 4200 discs."
Special fluid with electrical properties
Overview
"An electric arc is the form of electric discharge with the highest current density. The maximum current through an arc is limited only by the external circuit, not by the arc itself.

An arc between two electrodes can be initiated by ionization and glow discharge, when the current through the electrodes is increased. The breakdown voltage of the electrode gap is a combined function of the pressure, distance between electrodes and type of gas surrounding the electrodes. When an arc starts, its terminal voltage is much less than a glow discharge, and current is higher. An arc in gases near atmospheric pressure is characterized by visible light emission, high current density, and high temperature. An arc is distinguished from a glow discharge partly by the approximately equal effective temperatures of both electrons and positive ions; but in a glow discharge, ions have much less thermal energy than the electrons.

Drawn arc
A drawn arc can be initiated by two electrodes initially in contact and drawn apart; this can initiate an arc without the high-voltage glow discharge. This is the way a welder starts to weld a joint, momentarily touching the welding electrode against the workpiece then withdrawing it till a stable arc is formed. Another example is separation of electrical contacts in switches, relays or circuit breakers; in high-energy circuits arc suppression may be required to prevent damage to contacts.

A low-frequency (less than 100 Hz) alternating current arc resembles a direct current arc; on each cycle, the arc is initiated by breakdown, and the electrodes interchange roles, as anode or cathode, when current reverses. As the frequency of the current increases, there is not enough time for all ionization to disperse on each half cycle, and the breakdown is no longer needed to sustain the arc; the voltage vs. current characteristic becomes more nearly ohmic."
https://en.wikipedia.org/wiki/Electric_arc

Another way of explaining, an Arc
During the opening of current carrying contacts, in a switch, the medium in between the opening contacts becomes highly ionized through which the interrupting current gets low resistive path and continues to flow through this path, even though the contacts are physically separated. During this flowing of current, from one contact to other, the path becomes so heated that it glows
...this is called an arc.

So, it looks like the size of an arc (if one is created) is dictated by the current of the circuit.
…& a low-frequency AC arc resembles a DC arc.
I also came across:

Paschen's law
Paschen's law is an equation that gives the breakdown voltage, that is, the voltage necessary to start a discharge or electric arc, between two electrodes in a gas as a function of pressure and gap length. It is named after Friedrich Paschen who discovered it empirically in 1889.
https://en.wikipedia.org/wiki/Paschen's_law

This seems to pertain...
...but, It's a little (a lot) beyond me, at this time.

 

[Functional Artist]

To be or not to be

To arc or not to arc
...that should be the question (he he)
Yup were talkin' about switches now
...but, this info probably pertains "across the board"

So, "What is the minimum amperage necessary to create an arc @ 60VDC?
...1 whole amp (1.0A) (1,000mA)?
...1/2 of an amp (.5A) (500mA)?
...1/4 of an amp (,25A) (250mA)?
...1/8 of an amp (.13A) (125mA)?
...1/16 of an amp (.07A) (62.5mA)?

It seems to me that for these low amp control circuits, if there is not enough amperage to produce an arc
...there should be no arc

& if an arc is not produced
...there should be very little possibility of damage (to the contacts)

& if there's not much possibility of any contact damage
...does it "really" matter what the "actual" rating is (if it's even known) of the switch being used?

* Remember, were talkin about 14.5mA & if we continue the math
...1/32 of an amp = .04A or 31.25mA
…& 1/64 of an amp = .02A or 15.63mA

So, it looks like (if my math is correct)
...14.5mA is only ~1/64 of an amp

Logical?

 

[Functional Artist]

Temperature issues?

Lets not forget the other main cause of damage in electrical circuits heat. (AC or DC)

Actually, it's the "build up" of excessive heat (beyond the "specified operating parameters")

But, it's NOT the conductors that usually fail, they just do the "heating up".
It's usually the insulator that fails like
...the insulation covering on a wire
...or the plastic housing that holds the terminals in a connector
...or even the housing/material that holds the contacts in a switch.

So, I guess it's time to discuss insulators a bit
First, here is some good "backstory" info
Wire
"IEC, abbr. for International Electrical Commission, is the oldest international organization for standardization. It is formed by the electro technical commissions from the countries around the world. IEC authority is world recognized.

CCC, abbr. for China Compulsory Certification, is a compulsory accreditation system in China. Its listed commodities must be approved by national indicated organization. In China, only after the acquirement of related certificate could the electrical products leave factory or custom and be sold or used in public place. Wire and cable are first class listed goods in China. Our wire product has an attached random code following the CCC mark printed upon the product and customer can identify the purchased product through inquire the random code.

Our company is a creditworthy manufacturer who is expert at the manufacture of high temperature resistant silicone rubber wire and cable. We have advanced production equipment. Our IEC 60245, IEC60245-3, IEC60245-1 and IEC60245-2heat resistant silicone rubber insulation wires are all spark and pressure test passers and ageing treated. They have outstanding insulation and mechanical performance. Our product is affordable for the trust from customers.

Huacheng is a professional Chinese standard heat resistant wire manufacturer, based in China. We offer a broad range of products, including AWM3304 high temperature high voltage silicone rubber wire, AWM 1577 heat resistant Teflon wire, AWM 5108 heat resistant electrical equipment lead wire, and more.

We are a professional VDE approved high temperature wire manufacturer in China. We also provide AWM3135 silicone rubber heat resistant wire, JGG-6KV silicone rubber insulation high voltage motor lead wire, AFP-300/500V high temperature leading wire, and much more."
http://www.wirescable.com/3-domestic-certified-wire.html

Now, we know that when we see CCC on switches & connectors this indicates that a product has a China Compulsory Certification.
…& also some more info on the "standards" that they go by

PVC Insulated Wire and Cable
"Brief Introduction
(a) Conductor
This PVC insulated wire uses the bare copper or tinned copper as the conductor. Configured with high purity copper rod, the tinned copper is designed into copper strands on request of rigid or flexible construction. It is consistent with the environmental protection rules and meets the 5 level of IEC standard, too. This conductor is flexible with extremely high conductivity.
(b) Insulator
As for the insulation part, our product uses the polyvinyl chloride, abbreviated as PVC plastic. The PVC is a kind of non-toxic eco-friendly material conforming to the RoHS rules. It incorporates a series of features like light weight, preeminent resistance performance against heat, moisture, flame, corrosion, chemical liquid, acid and alkali. Due to the excellent thermal stability, this material is capable of working as several kinds of temperature rating, like 70ºC to 80ºC, 90ºC and 105ºC.
Application
This PVC insulated wire and cable is applied to cooperate with the wire harness, lighting device, instrument, electric panel and electrical equipment working in high temperature places.

Technical Data
Voltage range: 300V, 500V, 600V
Temperature rating: 800ºC, 90ºC, 105ºC
Voltage test: 1500V-2000V
Spark test: 4000V-6000V
Color: Red, white, yellow, green, blue, black, transparent, double-color, etc."
http://www.wirescable.com/10-pvc-insulated-wire-cable.html

The (300V 105*C) PVC insulated wire is the type used in most 12V automotive circuits
...& also for most of the circuits on 24V & 36V electric scooters & go karts.

On these "lower" voltage scooters & go karts, this type of wire is used on both the "big" power "battery/motor" circuits (~10g.)
...& also for the "small" power "signal/control" circuits (~18g.) too.

On the larger 48V & 60V EV (electric vehicle) speed controllers, the PVC type of wires are still used for the "small" control circuits (~18g.)
...but, on the "big" power wires (~10g.) they seem to have "stepped it up a bit" & use wire with heat resistant silicone rubber insulation, labeled 60245 IEC 03 (YG) 300/500V 2.5mm(2).

IEC 60245 Heat Resistant Silicone Rubber Insulation Wire
"Parameters
Rated Voltage: 300/500V
Rated temperature:-60℃~+180℃
Conductor: Multi-piece or single piece nickel-coated, tin-coated, silver-coated copper wire
Insulator: silicone rubber
Applicable for high temperature environment such as electron, electrical household appliance, lamps and lanterns, combustion equipment
Wire Lettering: CCC A005640 60245 IEC 03(YG)(0.5mm2~16mm2) 180℃ 300/500V"
http://www.wirescable.com/3-1-silicone-rubber-insulation-wire.html

So, this indicates that the electrical engineers, at the Chinese factory('s) that make these speed controllers, decided that for the "smaller" voltage speed controllers (up to 36VDC) the PVC insulated thin strand copper wires was adequate to use for ALL of the circuits (big) power & (small) control.
&
The PVC insulated thin strand copper wires also seem to be adequate to use for the "small" control wires on the 48V & 60VDC speed controllers
...but, for the "big" power wires they chose to use thin strand copper wire with the heat resistant silicone rubber insulation. (must of wanted or need a higher level of temp protection)

* I also noticed that "they" use the same Namz connectors on ALL of these ELV (extra low voltage) speed controllers/systems (12V up to 60V)
…& also on ALL circuits big "power" & the small "control" ones too.

So, this indicated that they can handle (at least) 72VDC & (up to) ~20A (cont.) & ~50A (max)

Actual ratings:
Small connectors with 2mm terminals & ~18g. wire = up to 10A
Large connectors with 4.5mm terminals & ~10g. wire = up to 50A