Power cord become so hot

[imanep]

Hello there,

Lately i have purchased 5 antminer S9 with bitmain Power supply.
I have purchased exactly same power cord on all my S9. All S9's are working just fine except one of them. if i turn on one of them after 5 min the power cord become so hot that you cant even touch the cable. I did replace the cable with another working machine and again  same thing happening.

Could you please help me in this case.

Regards

[Raymond_B]

Hello there,

Lately i have purchased 5 antminer S9 with bitmain Power supply.
I have purchased exactly same power cord on all my S9. All S9's are working just fine except one of them. if i turn on one of them after 5 min the power cord become so hot that you cant even touch the cable. I did replace the cable with another working machine and again  same thing happening.

Could you please help me in this case.

Regards

You need to provide more info. What size circuit are you running these on? Are all 5 on one circuit? Is it 220v or 110v? Are you running a PDU or some sort of power strip, etc, etc.

[EncoreMining]

Guessing something is wrong with your power supply. Hot cords are bad. Warm cords are ok. There might be a loose wire somewhere in the loop. I would switch out power supply’s with one of your others and see if the issue still occurs.

[HoleShot]

To find the faulty piece you can always exchange one component at a time with one from a known working system.

When the problem moves to the other system, you'll have identified the faulty piece which is the one you moved.

[lrowland21093]

Wow, hot power cords are bad - to me even a warm power cord is concerning.  Why use something that has a chance of causing a fire.

Usually cords will have a amperage rating on this or they will be labeled with the gauge of wire.  Many IEC PSU style cord are only 16 (max 10A) or 18 gauge (max 7A).  If you are running on 110V with an S9 it will pull about 1500W which is nearly 14Amps.  Running anything that close to or over its max rating is VERY bad idea - it is how lots of house fires are started.

You should run the S9 from a 220/240V circuit or at least get a power cable rated for at least 15A  (14 gauge and 10 feet or less).

Here is a 14 gauge one that is very affordable if you are running on 110V (it will still get warm but not hot):
https://www.amazon.com/Tripp-Lite-Heavy-Duty-IEC-320-C13-P007-006/dp/B0027JRMD0

[QuintLeo]

16 AWG is actually rated for 10 amps, not 13 - and AWG 18 is rated for 7 amps IIRC.
It is RARE to see "amperage" rating on a power cord, usually if there is such a rating it's on one of those "wrap-around label" things that tend to get torn up or removed over time.


 If the power cords are all the same and the one on a specific power supply is getting hot when the others are not, check to make sure you don't have hot air blowing ON that cord - otherwise you probably have a faulty power supply.

[lrowland21093]

QuintLeo, thank you.  I edited it so there is not bad information posted.
The funny thing is I have a 16AWG PSU cable here with a 13A paper tag on it!  It is some nameless brand so it has to be mislabeled.  I double checked and you are right about the ratings.
Again, thank you.

[EncoreMining]

Alsways bigger cord. Always.

[QuintLeo]

QuintLeo, thank you.  I edited it so there is not bad information posted.
The funny thing is I have a 16AWG PSU cable here with a 13A paper tag on it!  It is some nameless brand so it has to be mislabeled.  I double checked and you are right about the ratings.
Again, thank you.

 Some cheap manufacturers don't like living within the NEC, especially those from areas that are not covered by the NEC like China.
 It might be labeled "correctly" for the area it's FROM (except that they don't USE the same type of power connectors outside of the USA except possibly in Canada and Japan).

[HoleShot]

https://www.ebay.com/itm/BYBON-6ft-14-AWG-SJT-Universal-Power-Cord-for-computer-printer-White-UL/112637947916?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649

I bought these via ebay and they are awesome.

I measured 0.1 ohm resistance on each conductor and am running S9s on them. They stay cool.

They have a 105F rated insulator instead of the typical 60F.

[QuintLeo]

Nothing uses 60F rated insulation. It doesn't EXIST.
Insulation is also rated in C not in F, and is COMMONLY 80C or 105C depending on the specific type.
I've never seen 60C for any sort of insulation in use in the last 35+ years.

Then there's Teflon, for when you need REAL high temp resistance (but it's expen$ive so it's rarely used outside of high-temp industrial gear or some Mil-Spec stuff).

[lrowland21093]

In my experience the failure on a hot cord rarely happens on the cord (unless a curtain catches fire).  The failure is normally at one of the two ends.
I actually saw an old HP server that had the IEC connection fused with the power supply a few years ago.  Of course, everything usually just stops working once the magic blue smoke is released.

[big al]

Since the cable has already been swapped I'm going to guess the PSU is shorting to ground somewhere.  Is the PSU getting hot?   

[HoleShot]

Nothing uses 60F rated insulation. It doesn't EXIST.
Insulation is also rated in C not in F, and is COMMONLY 80C or 105C depending on the specific type.
I've never seen 60C for any sort of insulation in use in the last 35+ years.

Then there's Teflon, for when you need REAL high temp resistance (but it's expen$ive so it's rarely used outside of high-temp industrial gear or some Mil-Spec stuff).

I just bought a Trip-Lite 3' SJT power cable with +60C printed right on the jacket. I also just bought 250' of 10/3 from home depot with +60C right on it. I'd say it's very common in residential applications.

I use 90C and 105C in commercial applications. 

[fanatic26]

I just bought a Trip-Lite 3' SJT power cable with +60C printed right on the jacket. I also just bought 250' of 10/3 from home depot with +60C right on it. I'd say it's very common in residential applications.

I use 90C and 105C in commercial applications. 

Your last post mentioned 105F and 60F as the temp ranges. I think thats the confusion.

[HoleShot]

ah yes, was up kinda late there.

[QuintLeo]

Nothing uses 60F rated insulation. It doesn't EXIST.
Insulation is also rated in C not in F, and is COMMONLY 80C or 105C depending on the specific type.
I've never seen 60C for any sort of insulation in use in the last 35+ years.

Then there's Teflon, for when you need REAL high temp resistance (but it's expen$ive so it's rarely used outside of high-temp industrial gear or some Mil-Spec stuff).

I just bought a Trip-Lite 3' SJT power cable with +60C printed right on the jacket. I also just bought 250' of 10/3 from home depot with +60C right on it. I'd say it's very common in residential applications.

I use 90C and 105C in commercial applications. 

 Might depend on the area and local codes, or the type insulation used - I honestly can't remember seeing "new" 60C rated insulation EVER, just on older wiring that we were ripping out to upgrade or replace.
 Power cords I've not paid attention to the temp rating though, since they're not in an enclosed space commonly routed in/through/next to insulation where heat retention is a major issue - 60C rating on THOSE wouldn't be any shock to me.

 I would NOT say that 60C insulation is common in residential applications - I'm not sure if it's even LEGAL under the NEC and in those locations that have adopted the NEC as part of their local code requirements (most of the USA) for in-the-wall wiring.

[HoleShot]

Nothing uses 60F rated insulation. It doesn't EXIST.
Insulation is also rated in C not in F, and is COMMONLY 80C or 105C depending on the specific type.
I've never seen 60C for any sort of insulation in use in the last 35+ years.

Then there's Teflon, for when you need REAL high temp resistance (but it's expen$ive so it's rarely used outside of high-temp industrial gear or some Mil-Spec stuff).

I just bought a Trip-Lite 3' SJT power cable with +60C printed right on the jacket. I also just bought 250' of 10/3 from home depot with +60C right on it. I'd say it's very common in residential applications.

I use 90C and 105C in commercial applications. 

 Might depend on the area and local codes, or the type insulation used - I honestly can't remember seeing "new" 60C rated insulation EVER, just on older wiring that we were ripping out to upgrade or replace.
 Power cords I've not paid attention to the temp rating though, since they're not in an enclosed space commonly routed in/through/next to insulation where heat retention is a major issue - 60C rating on THOSE wouldn't be any shock to me.

 I would NOT say that 60C insulation is common in residential applications - I'm not sure if it's even LEGAL under the NEC and in those locations that have adopted the NEC as part of their local code requirements (most of the USA) for in-the-wall wiring.

†Allowable ampacities shown are for general use as specified by the National Electrical Code,
2005 Edition, section 310.15 unless the equipment is marked for use at higher
temperatures the conductor ampacity shall be limited to the following:
60°C - When terminated to equipment for circuits rated 100 amperes or less or marked for
size 14 through 1 AWG conductors. MTW wet locations or when exposed to oil or coolant.
75°C - When terminated to equipment for circuits rated over 100 amperes or marked for
conductors larger than size 1 AWG. THWN-2 when exposed to oil or coolant. MTW dry locations.
90°C - THHN dry locations. THWN-2 wet or dry locations. For ampacity derating purposes.

So now you know what is legal in the NEC.

If your wiring is rated as THHN or THWN-2 if wet, then you can use the 90C ampacity chart.

And yes, wiring not THHN rated is available.