I have a 10' extension cord 14 AWG. Load is MAC5200 compressor with 14A on the nameplate.

Cheers

 

Oh my, the cord is 16 AWG not 14.

 

Ampacity of 14g = 15amps.
16awg = 10amp

 

Ampacity of 14g = 15amps.
16awg = 10amp

What kind of damage would you expect from use a smaller conductor? Being 14 amp is between the two obviously 14 gauge is the minimum..

 

I was in a pinch today and had to use this cord. The compressor says 13.8A at maximum pressure which it was not at. The unit also had a thermal breaker. Hopefully little damage was done to my poor compressor.


Also, wouldn't a motor like this only draw the rated current at startup then drop?

 

This is from the manual. Evidently my 10' 16 guage cord is within tolerance. I'll be using a larger conductor in the future but I'm still scratching my head at the differences in numbers found on different units and the internet.

 

It won't hurt your compressor motor. The resulting fire from an overloaded cord may cause some damage however.

 

The nameplate current for most motors is at rated load. So the current after starting will depend on the pressure being delivered. An undersized cord will allow more of a voltage drop, but unless the motor has to struggle when starting you should have no problems unless you are loading the motor to it's rated output.

 

The resulting fire from an overloaded cord may cause some damage however.

7.9 watts of heat over 10 feet of wire is going to start a fire? I doubt a human hand could even tell that that cord is warmer than ambient.

 

7.9 watts of heat over 10 feet of wire is going to start a fire? I doubt a human hand could even tell that that cord is warmer than ambient.

and yet that is a major contributor to fire data. If your air consumption is high, your cable heat increases, and if covered with a flammable material, it may become another statistic

 

Just don't coil or cover the cord, until you can get piece of mind using a bigger cord.

Personally I would use 12 gauge from a well known company, and BTW most problems are caused at the plug or outlets of the cord.

Edited 10 to 12 gauge.

 

Thanks to everyone for the comments. The pressure was at around 80% of maximum and the duty was far less than the 50% maximum specified in the manual.

I monitored the setup all day even though it was outside. Indeed I could not detect any warmth in the cord after the on cycle ended.

I know cords are a major cause of issues but I've seen guys abuse their same brand compressors far worse than I ever will and they still function! The point of this topic is to try and see at which point there is truly an element of danger. Obviously there should always been some breathing room but I often wonder how much was added by the manufacturers to prevent dummies from blowing themselves up.

 

7.9 watts of heat over 10 feet of wire is going to start a fire? I doubt a human hand could even tell that that cord is warmer than ambient.

Ever grab a 3W night light while it's been glowing for a while? You'll let go pretty quick at first. Then in anticipation of the heat you may touch the bulb in short increments while unscrewing it from its base. Then bobble it back and forth in your hand until it cools sufficiently. 8W is pretty warm. And like others have said, under a rug or other flammable material and you're asking to become a part of the statistics.

 

8W is pretty warm.

What an odd statement. Watts is not a measure of temperature. The human brain dissipates about 30W. Perhaps that is why there are so many hotheads on this forum (myself included.)

 

I once worked for a dude that tried to get me use an angle grinder that had a short on a small cord. The irony is he has an electrical engineering degree. I had to argue with him about the safety of this.

The moral of the story is people do dumb things when their objective isn't logical or effective. In his case, he thought he was smart and is cheap. I'll never forget this because his actions laid the foundation for me to be electrocuted.

 

Long before there is any major heat issue there will be an obvious performance degrading that is hard to ignore.

Of course another option will be to get a longer air hose and move the compressor closer to the power source. We should have thought about that much sooner.

 

Long before there is any major heat issue there will be an obvious performance degrading that is hard to ignore.

Of course another option will be to get a longer air hose and move the compressor closer to the power source. We should have thought about that much sooner.

There are benefits to shorter air lines. I lugged my last compressor to the panel every time and it still crapped out less than 2 years old. I blame the CEO at Home Depot.

 

 

Some compressors of the noisy universal motor type are only intended for home use in pumping up bike tires every other month during the summer. Those units will never last when used for normal commercial duty. A very few of them list the maximum duty cycle, mos do not bother. I have been asked to repair a few of them and when the problem is a failed motor it will cost more to repair than to replace. An induction motor , or possibly a brushless DC/AC motor, is the only way to go. Unless some more exotic type like repulsion/induction is selected.

 

A lot of times these construction type compressors won't get up to speed with too small of a cord. It's pretty obvious if you listen, but if you don't realize what is happening there is a chance of overheating the motor. Most likely the cord will go before the motor, but under the right conditions it will destroy the motor before the cord.

They don't have a big tank, but will deliver more air than most single stage compressors. They aren't built the same.