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Recommended wire gauge for JVS & Model 3 harnesses?

kazuo

kazuo

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I recently had some custom harnesses made for a bunch of different use cases:
* Sega PSU to JVS
* Mean Well PSU to Model 3
* Harnesses to swap between the two above, because I’m lazy

The seller appears to have used what looks to be either 20 or 18 gauge wire; I can’t tell for sure, because the sheath doesn’t seem to have the AWG wire gauge printed on it. Instead. It seems to have some other thing printed on it: 0.5 KHD LFV
I found a data sheet, but unsure how useful this actually is. Just says the max voltage is 300V, nothing about amp draw.
https://khd.co.jp/assets/product/pdf00000009.pdf

Looking at a few harnesses I have here, including a Sanwa Model 3 harness and a Capcom JVS harness, they all seem to use 16 AWG wiring. I feel like they didn’t do it “just because”, but I’m not an expert, which leads me to my question: is ~20-18 AWG wire safe to use for JVS and Model 3 power wiring? Am I overthinking this? I’m not an expert, which is why I thought I’d ask all of you for some opinions/technical observations.

Some pictures of what I am working with below. I’ve left notes so you know which harness(es)/wire(s) are which. Thanks!

HJ9E8x5m.jpg

0.5 KHD custom on left, 16 AWG Sanwa Model 3 on the right

YhWyC3m.jpg

0.5 KHD custom on top, 16 AWG Sanwa Model 3 on the bottom
 
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It really depends on how many wires you intend on using in your harness. You can probably get away with 18AWG if you use two wires for 5V and two for 3.3V. (12V can be on 18AWG). If you’re only going with one wire for each voltage, use 16AWG. Using a thicker gauge wire will never harm your setup but using too thin wires may result in voltage drop. Grounds are very important too. Use as many ground wires, (and same gauge) as you have power wires.

For what it’s worth, most arcade harnesses used 600V UL1007 wiring from the manufacturers.

Edit: you can also get away with 20AWG if you used four wires for 5V, and four for 3.3V, (two for 12V) but you’re probably better off using fewer thicker wires.
 
0.5mm2 cross-sectional area is 20AWG. How long are these wires?

Also, what is going in that last pic? Where does that connector plug into?

Looks pretty bad for custom work.
 
Sorry, I admittedly made that post in a bit of a hurry, and I left out some details.

The last two pics are attempts to compare the wire gauge of the custom harnesses with wires off other harnesses where I know for sure what the wire gauge; the third picture was comparing to an 18 AWG wire from a wire roll I had laying around, and the fourth photo (with the molex power harness that presumably led to the question!) was comparing the custom harness wire gauge to another 18 AWG wire off said molex power harness. Both the 18 AWG wires I had were slightly different thickness such that I was having trouble deciding if the custom harnesses were 18 or 20 AWG. To be clear, the last photo that led to your question was of two different harnesses, which is where I think the confusion came from. Sorry about that.

Since it sounds like we’re sure they’re 20 AWG at this point (thanks to you, nem!), I've deleted those last two pics to avoid any further confusion on this point.

I don’t have access to the harnesses at the moment, but I’m pretty sure they’re ~0.6m or less. Might be 1m at most. I’ll update once I’ve gotten a chance to look.

Thanks for all the feedback so far!
 
Depends on how long you want to make them, but in general I would never use smaller than 18AWG, unless you like voltge drop - use 2x18AWG for 5V, 3.3V and GND (important..).
 
Thanks, zim! Sounds like you and kikaso have similar feedback... might try to reach out to the seller and see if they can re-do the harnesses with either 16 AWG, or x2 18 AWG for each of the power leads. The harnesses are all around 0.6m - 0.8m, so under a meter. Not sure if that impacts things at all.

I don't really mind cranking up the PSU a bit to compensate, but I do kinda worry about other risks at play here. Perhaps just asking for a do-over is the right way to go. No idea why he used 20 AWG - I probably should've asked for 16 AWG, but that's what I get for assuming he'd use thicker wiring for this.
 
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kazuo said:
The harnesses are all around 0.6 cm - 0.8 cm, so under a meter. Not sure if that impacts things at all.
Click to expand...
Always try and use the shortest possible harness for power. Longer wires introduce more resistance potentially leading to voltage drop.
 
kazuo said:
No idea why he used 20 AWG - I probably should've asked for 16 AWG
Click to expand...
Hi, is it possible they used AWG 20 because it’s easier to crimp the terminals on thinner wire?
AWG 16 is thicker copper so more difficult with the same male/female crimp terminal.

At my work we use always AWG 20 to put terminals on, then goes in a molex connector.
But this is to connect leds to a PS, no high power is drawn, 500 - 700 mA.
I would say : thicker wire = more safe

I notice : metal is outside the connector on the left ?
 
Wire gauge will be limited by the connector used.
Generally the housing will support a range of wire sizes and the pins themselves will support a smaller range
the Filter Board on model 2 and 3 hardware is all JST NH Series which supports a 30AWG - 22AWG range
and there are two pin sizes for this family connector, the smaller pin size supports 30AWG - 28AWG and the larger one supports 28AWG to 22AWG
https://www.jst-mfg.com/product/pdf/eng/eNH.pdf?63b5deb63e408

This is the reason these games use LOTS AND LOTS of pins on the power connectors, because being limited to 22AWG per wire means you have to use many wires in order to carry the current needed to run the system.
 
sammy_v said:
I notice : metal is outside the connector on the left ?
Click to expand...

Yes. Long story short, we ended up using through-hole connectors for the male end because I goofed up and ordered the wrong connector. That particular pin is a NC, it was left floating. I suppose it'd be "better" to snip it off, but it's a NC on both ends so I'm not that concerned about it.
 
kazuo said:
Yes. Long story short, we ended up using through-hole connectors for the male end because I goofed up and ordered the wrong connector. That particular pin is a NC, it was left floating. I suppose it'd be "better" to snip it off, but it's a NC on both ends so I'm not that concerned about it.
Click to expand...
If it’s not connected on both sides you may as well remove it, it has no function.
The last thing you want is making a short- circuit.
This aside, best wishes for the New Year !

Sammy
 
I use 18 but I feel like you could get away with 20AWG.

I usually go 18 for anything power and 22 for signal stuff

edit: I should say I run all available voltage leads to where they need to be. So for something JVS I never single lead a voltage at 18 AWG. I still would highly presume 18 would be sufficient for the power draw of most stuff, but I never use 1 wire per pin
 
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