Is it safe to use 22awg wire with RTX 30?

[danielzy]

Hi, hoping to get some love from @jonnyGURU but of-course would appreciate anyone's else comment!

 

The situation is like that -

I am making a custom cable for my 3080FE using the official Astron terminals which supports up to 9A.

The datasheet of this terminal by nVidia says you should use a 16g wire (link above) - but I don't understand why.

 

My 3080 never pulled more than 350W so about 60W per terminal, in a 12V circuit that's not even 5A.

A UL1007 22AWG seems to support up to 10A @ 86F so theoretically I should be able to use that gauge without any issues, right?

 

I was thinking that nvidia doesn't know what every single manufacture will do, some can try to wire all 12 pins to a single 8 pin socket, which in this case, 16g may be required.

 

My PSU is an SF750 and I will of-course use two 8 pin connections.

[--SID--]

No. Even the worst PSU with PCI-e connector don't use 22awg. Use 13A HCS connectors and 18awg at least.

[danielzy]

7 minutes ago, --SID-- said:

No. Even the worst PSU with PCI-e connector don't use 22awg. Use 13A HCS connectors and 18awg at least.

I am not taking a side in the arms race of PSU manufacturers.

I am asking about a specific scenario (each pin in the GPU is wired to a single pin in the PSU) and hoping to get some real answers.
If you say I can't do that, please provide some actual data to back your answer.
Saying don't do X because everybody else does Y doesn't help me much.

[OhioYJ]

33 minutes ago, danielzy said:

A UL1007 22AWG seems to support up to 10A @ 86F so theoretically I should be able to use that gauge without any issues, right?

Did you forget to include wire length and perhaps voltage drop in your calculations? There is no way I would want to run 10 amps across a 22 AWG wire for any length of time. That's not safe (IMHO).

[danielzy]

1 minute ago, OhioYJ said:

Did you forget to include wire length and perhaps voltage drop in your calculations? There is no way I would want to run 10 amps across a 22 AWG wire for any length of time. That's not safe (IMHO).

I did not, I checked several calculators and read several articles about the subject.

I also edited the main post to provide some more reasoning - 

 

My 3080 never pulled more than 350W so about 60W per terminal, in a 12V circuit that's not even 5A.

A UL1007 22AWG seems to support up to 10A @ 86F so theoretically I should be able to use that gauge without any issues, right?

 

For example: https://www.wirebarn.com/Wire-Calculator-_ep_41.html

[--SID--]

22awg is rated for 3A

16awg is rated for 10A

22awg has a 3 time higher resistance than 16awg.

 

With 22awg you're making a fire hazard of your excellent PSU.

 

[danielzy]

2 minutes ago, --SID-- said:

22awg is rated for 3A

16awg is rated for 10A

22awg has a 3 time higher resistance than 16awg.

 

With 22awg you're making a fire hazard of your excellent PSU.

 

Thank you this is why I created this thread.

What I don't understand is how come the picture you attached is so different than something like this, for example: https://docs.rs-online.com/4471/0900766b813a26c2.pdf

[Guest]

2 hours ago, danielzy said:

Thank you this is why I created this thread.

What I don't understand is how come the picture you attached is so different than something like this, for example: https://docs.rs-online.com/4471/0900766b813a26c2.pdf

Yeah. There's definitely something misleading about that table. 

 

Your going to see significant voltage drop using 22g.

 

I mean, look at the differences I found just between 18g and 16g.

[danielzy]

1 hour ago, jonnyGURU said:

Yeah. There's definitely something misleading about that table. 

 

Your going to see significant voltage drop using 22g.

 

I mean, look at the differences I found just between 18g and 16g.

I searched both in your website and through threads you started and couldn't find it, mind sharing a link?

Also - I ruled out 22g and focusing on either 20g (preferably) or a 18g with a very thin isolation (which will probably be very expensive)

[Guest]

2 hours ago, danielzy said:

I searched both in your website and through threads you started and couldn't find it, mind sharing a link?

Also - I ruled out 22g and focusing on either 20g (preferably) or a 18g with a very thin isolation (which will probably be very expensive)

Why are you opposed to just using 16g like you're supposed to?

 

 

[danielzy]

2 minutes ago, jonnyGURU said:

Why are you opposed to just using 16g like you're supposed to?

 

 

Very simple - it can't be sleeved as nicely.

Correct me if I'm wrong but without the pigtailing there was only a very small voltage drop changing the 16g to the 18g.

Also - if I am not mistaken nvidia says that up to 8% in drop in voltage is harmless, no?

We also don't know the quality of the 18g compared to the 16g...

[Guest]

1 hour ago, danielzy said:

Very simple - it can't be sleeved as nicely.

Correct me if I'm wrong but without the pigtailing there was only a very small voltage drop changing the 16g to the 18g.

Also - if I am not mistaken nvidia says that up to 8% in drop in voltage is harmless, no?

We also don't know the quality of the 18g compared to the 16g...

If you can't nicely sleeve 16g wire with paracord or whatever you're using, you're doing something wrong.  I have plenty of the 12-pin and even 12+4-pin connectors that use 16g wire and are absolutely gorgeous.

 

Maybe the problem is not the gauge of the wire, but the quality of it.  The higher temperature wire that Nvidia and Astron use for their 12-pin and 12+4-pin connectors is a completely different material and is much thinner than your "typical cable" despite being rated for up t 125 degrees C.

 

[danielzy]

3 minutes ago, jonnyGURU said:

If you can't nicely sleeve 16g wire with paracord or whatever you're using, you're doing something wrong.  I have plenty of the 12-pin and even 12+4-pin connectors that use 16g wire and are absolutely gorgeous.

 

Maybe the problem is not the gauge of the wire, but the quality of it.  The higher temperature wire that Nvidia and Astron use for their 12-pin and 12+4-pin connectors is a completely different material and is much thinner than your "typical cable" despite being rated for up t 125 degrees C.

 

I can sleeve the 16g no problems but because the connector of the FE is so narrow it makes it looks like a funnel (a row of six 16g wires with sleeves is much wider than the 12p connector) and I don't like that look. 

 

Yes there will be some voltage drop, yes it is definitely not "best practice" - but will it actually be resulted in real life difference?

 

I can also use PTFE 18g wire which has a very think insulation, but they are a bit more difficult to get.

 

Bottom line the question is if I can safely use a 20g wire for my 3080FE given that I don't do any pigtailing and will use a high quality wire.

Tell me there is a fire hazard, or that I will experience crashes or something like this - and I will ditch the 20g and get the 3-4 times more expensive PTFE 18g.

[A Beautiful Lie]

PSA: While they offer international shipping also, in the US, custom / DIY sleevers have success using Lutro0 / MainFrame Customs thin-jacket insulation 16awg & 18awg wire in black or white (among most other basic cable & wiring supplies: connectors, terminals, sleeve, tools etc), all at affordable cost ... scroll to see MainFrameDave's custom 3090Ti 12pin FE cables

 

Get their 16g if it's size will work, or 18g --> ditch the 20g (ewww)

 

 

[Guest]

11 hours ago, danielzy said:

I can sleeve the 16g no problems but because the connector of the FE is so narrow it makes it looks like a funnel (a row of six 16g wires with sleeves is much wider than the 12p connector) and I don't like that look. 

 

Yes there will be some voltage drop, yes it is definitely not "best practice" - but will it actually be resulted in real life difference?

 

I can also use PTFE 18g wire which has a very think insulation, but they are a bit more difficult to get.

 

Bottom line the question is if I can safely use a 20g wire for my 3080FE given that I don't do any pigtailing and will use a high quality wire.

Tell me there is a fire hazard, or that I will experience crashes or something like this - and I will ditch the 20g and get the 3-4 times more expensive PTFE 18g.

The voltage drop will require the card to draw more current. The increase in current will increase the cable temperature.  With 16g wire, you're already pretty close to spec.  I'm guessing you're also looking at 85C wire as well.

 

If your cable looks like a "funnel" then you're not using the right parts.  

 

I'm not going to recommend anyone use anything that far out of spec.  There's a reason everyone uses only 16g and 18g (17g at the thinnest for the 12-pin connector).

 

The PSUs use 18g and 16g cables for a reason.  If they wanted to save money and go with 20g and 22g, they would (it would save a lot of money), but because they're not stupid and don't want to set a bunch of fires, they don't.

 

I'm done here.  You do whatever you want.

 

[danielzy]

29 minutes ago, jonnyGURU said:

The voltage drop will require the card to draw more current. The increase in current will increase the cable temperature.  With 16g wire, you're already pretty close to spec.  I'm guessing you're also looking at 85C wire as well.

 

If your cable looks like a "funnel" then you're not using the right parts.  

 

I'm not going to recommend anyone use anything that far out of spec.  There's a reason everyone uses only 16g and 18g (17g at the thinnest for the 12-pin connector).

 

The PSUs use 18g and 16g cables for a reason.  If they wanted to save money and go with 20g and 22g, they would (it would save a lot of money), but because they're not stupid and don't want to set a bunch of fires, they don't.

 

I'm done here.  You do whatever you want.

 

Thank you for taking the time. I appreciate that. I will go for 18g PTFE.

[danielzy]

7 hours ago, A Beautiful Lie said:

PSA: While they offer international shipping also, in the US, custom / DIY sleevers have success using Lutro0 / MainFrame Customs thin-jacket insulation 16awg & 18awg wire in black or white (among most other basic cable & wiring supplies: connectors, terminals, sleeve, tools etc), all at affordable cost ... scroll to see MainFrameDave's custom 3090Ti 12pin FE cables

 

Get their 16g if it's size will work, or 18g --> ditch the 20g (ewww)

 

 

That's where my problem started. I don't have time to tell the whole story, but tl;dr MAINframe 18g can't be used with the combs I wanted despite them being designed for that very same cable (a miscommunication between manufacturers).

 

I came here to ask for more opinions, not to argue, and it seems everyone including people that really know what they are doing are really against it, so I am ditching the 20g idea. Will go for a Teflon insulated 18g despite the cost.

[ForceWorx]

14 hours ago, jonnyGURU said:

Why are you opposed to just using 16g like you're supposed to?

 

 

So after a lot of research I found some 20awg wire that has the following specs

 

APPLICATIONS:

• All hi-temp or hi-rel application
• Used in critical, high performance; military; commercial; racing

 

FEATURES:

• Available in 26, 24, 22, 20, & 18 AWG
• Silver plated copper conductor
• Teflon insulation
• 26 & 24 AWG are 7 strand, all other gauges are 19 strand
• Resistance to oils, alkalies, acids, flame, and moisture
• Meets Mil 16878/4 specs

 

SPECIFICATIONS:

• Voltage Rating:  600 Volts
• Insulation:  Teflon
• Max. Temperature:  200°C
• Colors:  Black, Brown, Red, Orange, Yellow, Green, Blue, Violet, Gray, White
• Spools:  25 and 100 feet

 

I called and spoke with the engineering department and they siad its rated for 5 to 11amps temperature dependent.

 

 

https://www.digikey.ca/en/products/detail/nte-electronics-inc/WT20-00-25/11653052

 

So this wouldn't work?

Should I avoid?

For reference I have a 3090 FE and an in win Classic Series C1250W

Just want to check.

 

Thanks

[danielzy]

7 minutes ago, ForceWorx said:

So after a lot of research I found some 20awg wire that has the following specs

 

APPLICATIONS:

• All hi-temp or hi-rel application
• Used in critical, high performance; military; commercial; racing

 

FEATURES:

• Available in 26, 24, 22, 20, & 18 AWG
• Silver plated copper conductor
• Teflon insulation
• 26 & 24 AWG are 7 strand, all other gauges are 19 strand
• Resistance to oils, alkalies, acids, flame, and moisture
• Meets Mil 16878/4 specs

 

SPECIFICATIONS:

• Voltage Rating:  600 Volts
• Insulation:  Teflon
• Max. Temperature:  200°C
• Colors:  Black, Brown, Red, Orange, Yellow, Green, Blue, Violet, Gray, White
• Spools:  25 and 100 feet

 

I called and spoke with the engineering department and they siad its rated for 5 to 11amps temperature dependent.

 

 

https://www.digikey.ca/en/products/detail/nte-electronics-inc/WT20-00-25/11653052

 

So this wouldn't work?

Should I avoid?

For reference I have a 3090 FE and an in win Classic Series C1250W

Just want to check.

 

Thanks

As you can see @jonnyGURU is really against it, and probably for a valid reason.

Voltage will drop, current will increase, and we don't know by how much without testing. 

[ForceWorx]

3 minutes ago, danielzy said:

As you can see @jonnyGURU is really against it, and probably for a valid reason.

Voltage will drop, current will increase, and we don't know by how much without testing. 

Fair I just want his opinion on this particular wire, and if he has any dealings with Alpha wire,

from what the engineer I talked with claimed it should be perfectly fine... I am no expert so

wanted to see what @jonnyGURU thought about it.

[A Beautiful Lie]

Interested readers: high GPU 'power concerns' peaked w/ the release of the AMD R9 295x2 way back in 2014: TDP 450w / TBP 500w (pushing the limits of dual-8pin power); Tom'sHardware breakdown at the time ('A lot has been written about AMD’s flagship violating standards and specifications') message clear: forget 20g, 18g minimum, 16g preferred --> The Math Behind GPU Power Consumption And PSUs ... easy to apply that same lesson to today's Nvidia 3000/4000 

[Dogzilla07]

4 hours ago, A Beautiful Lie said:

easy to apply that same lesson to today's Nvidia 3000/4000 

Even more for the new Nvidia/AMD cards, they spike much more, the R 295x2 didn't.

[danielzy]

13 hours ago, A Beautiful Lie said:

Interested readers: high GPU 'power concerns' peaked w/ the release of the AMD R9 295x2 way back in 2014: TDP 450w / TBP 500w (pushing the limits of dual-8pin power); Tom'sHardware breakdown at the time ('A lot has been written about AMD’s flagship violating standards and specifications') message clear: forget 20g, 18g minimum, 16g preferred --> The Math Behind GPU Power Consumption And PSUs ... easy to apply that same lesson to today's Nvidia 3000/4000 

That's not at all what the article said.

Also 20g wires are being used in the automotive industries for up to 10A where the stakes are significantly higher.

 

Anyways, in the last week I discussed this with a lot of people, one of them actually works as an electrical engineer at nvidia in one of the boards design team, here is the summary:

- not all cables are the same

- nothing can be decided without reading the specific cable specification

- one should not transfer more than 80% of the wire specification current

- the higher the current the higher the temperature

- there is nothing wrong with high temperature wire as long as it is built for that

- one should not get wires from china to save a few bucks, those are much bigger fire hazard than 16\18\20g

- voltage drop can easily be calculated using the wire's resistance which is written in its spread sheet

 

One thing to consider is that the gpu doesn't guarantee to pull an even amount of current through each 12v wire.

I checked this with a multimeter (at the GPU side of-course) and indeed under full load (my 3080 is slightly undervolted):

 

Using a single original cable from the PSU with pigtailing:

3 wires - 3.75082577A

3 wires - 3.14656269A

 

Using two cables from the PSU:

3 wires - 3.74289246A

3 wires - 3.17399056

 

As you can see half the wires transferred significantly more current than the other half.

 

Bottom line, 20g should be fine if you know what you are doing, is it best practice? no, of-course not. 

But the fact that 16g is better than 20g doesnt make 20g bad.

I guess that with thicker wire one have much more room for errors.

 

Personally - I decided to go on the safer side and bought a thin, Teflon insulated 18g wire from Alpha, despite the fact that 20g would have probably been perfectly fine too.