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Old 01-29-2017, 04:32 PM
Mangosteen Mangosteen is offline
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Extension cord will harm treadmill?

The electric cord that came attached to my treadmill is about four feet short of where I want to plug it in to the wall.

The manual says no extension cords should be used.

Will a short (four foot) heavy duty extension cord ruin my treadmill or burn my house down?
  #2  
Old 01-29-2017, 05:01 PM
jz78817 jz78817 is online now
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Quote:
Originally Posted by Mangosteen View Post
The electric cord that came attached to my treadmill is about four feet short of where I want to plug it in to the wall.

The manual says no extension cords should be used.

Will a short (four foot) heavy duty extension cord ruin my treadmill or burn my house down?
what's the rated current draw of your treadmill? It should be either in the user manual or printed/embossed on the treadmill near where the cord attaches.
  #3  
Old 01-29-2017, 05:22 PM
electronbee electronbee is offline
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Probably a safety precaution. In a house, the circuit breakers are rated for 100% for (I think) 15 minutes, and 50% current draw can be sustained indefinitely.

I would be surprised if it needed that much though. Any ways, I think an extension cord rated for the branch circuit would be fine, which would be 15 amp. If you want to be a belt and suspenders type person you can get one rated for 20 amp. After that the cord will have a different plug.

OOC, what make/model?
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Old 01-29-2017, 05:24 PM
jnglmassiv jnglmassiv is offline
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Quote:
Originally Posted by Mangosteen View Post
Will a short (four foot) heavy duty extension cord ruin my treadmill or burn my house down?
Heavy duty is the right thing to use here. Use a good quality 'appliance cord' that's no longer than required.

The manual says to not use them because people will use flimsy cords that get too hot or long ones that get wrapped into the tread belt and pull the family dog into the gear train. It's safer and easier for them to say to never use one rather than trying to detail which ones are suitable.
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Old 01-29-2017, 05:57 PM
Crafter_Man Crafter_Man is offline
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How much current does the treadmill draw?

Regardless, I love overkill. If you have a 20 A receptacle, I would use this extension cord.
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Old 01-29-2017, 06:02 PM
Mangosteen Mangosteen is offline
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Originally Posted by electronbee View Post
Probably a safety precaution. In a house, the circuit breakers are rated for 100% for (I think) 15 minutes, and 50% current draw can be sustained indefinitely.

I would be surprised if it needed that much though. Any ways, I think an extension cord rated for the branch circuit would be fine, which would be 15 amp. If you want to be a belt and suspenders type person you can get one rated for 20 amp. After that the cord will have a different plug.

OOC, what make/model?
Its a Precor 9.31, 8 years old.
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Old 01-29-2017, 06:02 PM
jz78817 jz78817 is online now
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as an example, the treadmill my mom has is marked 120VAC / 60Hz / 15A. which is probably the peak current, for a treadmill that would be in short "spikes." a heavy duty extension cord for that rated current would probably be OK. definitely don't want to use one of those thin, flimsy ones like for Christmas lights.
  #8  
Old 01-29-2017, 06:04 PM
Mangosteen Mangosteen is offline
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Originally Posted by Crafter_Man View Post
How much current does the treadmill draw?

Regardless, I love overkill. If you have a 20 A receptacle, I would use this extension cord.
I saw this type has a four foot cord.


https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
  #9  
Old 01-29-2017, 06:08 PM
Mangosteen Mangosteen is offline
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Originally Posted by jz78817 View Post
as an example, the treadmill my mom has is marked 120VAC / 60Hz / 15A. which is probably the peak current, for a treadmill that would be in short "spikes." a heavy duty extension cord for that rated current would probably be OK. definitely don't want to use one of those thin, flimsy ones like for Christmas lights.
Mine is marked 120 VAC 50/60 Hz 12A
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Old 01-29-2017, 06:18 PM
JKilez JKilez is offline
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Quote:
Originally Posted by Mangosteen View Post
Will a short (four foot) heavy duty extension cord ruin my treadmill or burn my house down?
To be safe, you should use an extension cord made with 14 gauge or 12 gauge wires. Most short length extension cords are 16 gauge or higher.
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Old 01-29-2017, 07:00 PM
Crafter_Man Crafter_Man is offline
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Originally Posted by JKilez View Post
To be safe, you should use an extension cord made with 14 gauge or 12 gauge wires. Most short length extension cords are 16 gauge or higher.
Yea, whenever I need to purchase a "permanent" extension cord for a "high power" device that has a 15 amp NEMA 5-15P plug on the power cord, I will first try and find a cord with 12 gauge wires. If I can't find a cord (in the length I want) with 12 gauge wires, then I'll opt for a cord with 14 gauge wires. (An extension cord with 14 gauge wires will work fine, but I like overkill. I'm weird that way.)

Keep in mind that short extension cords with 12 gauge wire will sometimes have a 20 amp NEMA 6-20P plug. So even if your appliance has a 15 amp (NEMA 5-15P) plug, the receptacle will need to be 20 A.
  #12  
Old 01-29-2017, 07:07 PM
jz78817 jz78817 is online now
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Originally Posted by JKilez View Post
To be safe, you should use an extension cord made with 14 gauge or 12 gauge wires. Most short length extension cords are 16 gauge or higher.
the nice thing is- at least at the major home improvement retailers- the packaging usually is clearly labeled with the wire gauge; you don't have to inspect the cord itself for any hard-to-see markings.
  #13  
Old 01-29-2017, 07:33 PM
RivkahChaya RivkahChaya is online now
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I have safely used extension cords with appliances, including oil-filled space heaters that say never, never use them. I always use heavy duty ones and check that they are a gauge up from the appliance. Like someone said above, the warning is mainly because people will use flimsy ones for small lamps, and they'll catch fire.

Another concern is that a long extension cord, longer than you need, should not be left coiled. It should be laid out so air can circulate around it in case it does get a little warm. It is hard to find short, heavy-duty cords.
  #14  
Old 01-29-2017, 10:07 PM
Melbourne Melbourne is offline
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Another problem with long thin extension cords with multiple junctions, is that there may be too much voltage drop during the start-up, when the motor draws 5-10 times as much current. This can, in extreme cases, cause the motor to burn out.

I dislike extension cords and power boards because they used to be involved in so many fires (i'm getting old). I would take the covers off and see if i could wire in a longer cord.
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Old 01-30-2017, 08:28 AM
ftg ftg is online now
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When they say don't do this, don't do this. The "But it worked for me." stuff is not at all good advice.

For a device like a treadmill there can be substantial loss of power in the extension cord which is hard on the motor and it will fail early. Note: the point of failure is most likely to be the treadmill, not the cord.

Corded weed cutters are a well known example of this. People use the wrong gauge extension cord and the motor burns out.

In theory you could use the a cord with the right gauge, the right plugs and the right length. Do you know how to calculate what "right" is here? I think not.

Last edited by ftg; 01-30-2017 at 08:29 AM.
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Old 01-30-2017, 08:32 AM
CalMeacham CalMeacham is offline
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But what happens if you take off?
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Old 01-30-2017, 10:05 AM
naita naita is offline
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Quote:
Originally Posted by ftg View Post
When they say don't do this, don't do this. The "But it worked for me." stuff is not at all good advice.

For a device like a treadmill there can be substantial loss of power in the extension cord which is hard on the motor and it will fail early.
If I get a short straight cord with the same gauge as what is supplying power to the socket on my wall, how far off "right" is it possible I am?
  #18  
Old 01-30-2017, 10:30 AM
watchwolf49 watchwolf49 is online now
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I'm hesitant adding anything here ... seems the manufacturer already attached a cord and did the math ... it's already at the safe limit for length and/or size ... if they say don't use an extension cord, then maybe this takes the matter over the safety limit ... perhaps the OP could describe the existing cord in terms of length and size ...

Copper wire makes for a good conductor, but not a perfect conductor ... there is a little resistance and the energy of the voltage drop is dissipated as heat ... so the longer the cord, the more resistance and more heat ... the smaller the wires, the more resistance and more heat ...

So, I'm running a little electric chainsaw at the end of 200 foot of extension cords (first 50' = 10 gauge, rest = 12 gauge) and things were getting quite warm ... like melting the plastic end caps warm ... maybe I could have caught something on fire if I hadn't cut through the cord when I did ...

My advice ... move your treadmill the four foot closer to the outlet you want to use ... it doesn't matter how low the risk of burning down your house ... the consequences of such to far far too great to chance it IMEIO ...
  #19  
Old 01-30-2017, 03:02 PM
BigT BigT is offline
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Find out the amperage, and then explicitly get an extension cord that is rated to handle that amperage. IF you can't find it, try to match the amperage that corresponds to your house wiring, usually 15 amps. Yes, that will mean the gauges mentioned above, but I would not go just by the gauge. The lower gauge, the better, however.

The reason you are told not to use an extension cord is that the vast majority are not so rated, and can get incredibly hot or short out. It is not some global restriction. It wouldn't make sense if it were--your house wiring is essentially just an extension cord that's permanently in place.

Sure, there is the added issue of the extension cord moving around. But, first off, you can minimize this yourself. Plus, the cords are usually quite thick and resist any sort of sharp bending, let alone any damage. (Still, avoid kinking the cords)

As long as the cords (including the plug ends) do not get hot, it is fine.
  #20  
Old 01-30-2017, 06:40 PM
Alley Dweller Alley Dweller is offline
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But then if I plug the treadmill into an outlet in my living room, the electricity has to run through 30 feet more wire than if I plug it into an outlet in my kitchen. Do I have to concern myself with this?

What difference does it make if the wire the electricity runs through is inside the wall (house wiring) or outside the wall (extension cord) when the wire is the same gauge?

Last edited by Alley Dweller; 01-30-2017 at 06:42 PM.
  #21  
Old 01-30-2017, 07:53 PM
K2500 K2500 is offline
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A four foot extension cord is unlikely to burn the house, or the machine, down(or up I suppose).

Name plate current ratings for consumer goods are unreliable at best, but conservatively at least. Home air compressors are the world's worst at this, or so I've noticed.

I've never owned a treadmill but if it's like most appliances the cord should be pretty easy to change for one that's four feet longer, depending on your apptitude. Changing the cord would eliminate the extra connection point, which is a common point of failure for cord and plug devices. Longer cords in multiple sizes are available with molded ends.
  #22  
Old 01-30-2017, 08:39 PM
watchwolf49 watchwolf49 is online now
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Quote:
Originally Posted by Alley Dweller View Post
But then if I plug the treadmill into an outlet in my living room, the electricity has to run through 30 feet more wire than if I plug it into an outlet in my kitchen. Do I have to concern myself with this?

What difference does it make if the wire the electricity runs through is inside the wall (house wiring) or outside the wall (extension cord) when the wire is the same gauge?
The problems occur at the connections ... the wires in your wall have no connections (or there better not be) ... all the connections should be in the boxes where they are always accessible ... and connections here are tight, complete and professionally installed ...

The problems with extension cords is where they plug into each other and/or the wall ... just them lil' prongs don't always make a great connection and that's where the heating problems occur ... in the OP's case, his 12 gauge extension cord should be fine ... but where he plugs in the whimpy 16 gauge power cord for the machine is where it will heat up ... perhaps dangerously so if these plugs are worn some ...
  #23  
Old 01-30-2017, 08:44 PM
Crafter_Man Crafter_Man is offline
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Originally Posted by Melbourne View Post
Another problem with long thin extension cords with multiple junctions, is that there may be too much voltage drop during the start-up, when the motor draws 5-10 times as much current. This can, in extreme cases, cause the motor to burn out.
True, but it is usually only a problem with long extension cords.

Let's say you have a 120 V device that draws 10 A. And you want to power it with a 100 foot extension cord.

What gauge wire should the extension cord be? Since you're pulling 10 A, you can safely use a 12 gauge, 14 gauge, or 16 gauge extension cord. But as you mentioned, there is another issue that must be considered: voltage drop along the cord. Assuming T = 70 C and doing the math we discover:

Using a 12 gauge extension cord, the voltage at the load will be 116.2 V (3.2% low).
Using a 14 gauge extension cord, the voltage at the load will be 114.0 V (5.0% low).
Using a 16 gauge extension cord, the voltage at the load will be 110.4 V (8.0% low).

The threshold is 5%. So a 12 gauge extension cord would work fine. A 14 gauge extension cord would be marginal. A 16 gauge extension cord could be bad... the voltage would be 8% low at the device. The device could be damaged, depending on what it is.
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Old 01-30-2017, 08:44 PM
Mangosteen Mangosteen is offline
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Does it help to unplug the treadmill after using it to allow the cord to cool down?

I use it 3 times a week for about 36 minutes each time.

Should I keep it unplugged when not in use?
  #25  
Old 01-30-2017, 08:51 PM
Crafter_Man Crafter_Man is offline
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Originally Posted by Alley Dweller View Post
But then if I plug the treadmill into an outlet in my living room, the electricity has to run through 30 feet more wire than if I plug it into an outlet in my kitchen. Do I have to concern myself with this?

What difference does it make if the wire the electricity runs through is inside the wall (house wiring) or outside the wall (extension cord) when the wire is the same gauge?
Indeed, the entire length of wiring between the device and the home's transformer matters. In my example above, I assumed (for simplicity's sake) the voltage at the receptacle is regulated at 120 V. This is not true, of course. A more thorough analysis would also include the length and gauge of the Romex wiring in the walls.

In buildings were there are very long runs of wiring, the electrician will increase the gauge of the wiring (to an appropriate size) to keep the voltage drop to less than 5% at maximum current. And there is the issue with temperature. It can get complicated...
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Old 01-30-2017, 09:04 PM
jnglmassiv jnglmassiv is offline
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Originally Posted by Mangosteen View Post
Does it help to unplug the treadmill after using it to allow the cord to cool down?
I use it 3 times a week for about 36 minutes each time.
Should I keep it unplugged when not in use?
IF the cord is getting warm, it will only do so when the device is in use and, most likely, when under significant load. For a treadmill, this is primarily during that initial few seconds as it comes up to speed. Unplugging the cord will not help anything powered down cool off. There may be other safety reasons to unplug it that aren't related to any electrical hazards like, say, a cat or child accidentally turning the thing on.

Go get an appliance cord from the hardware store and rest easy. Folks use these for thirsty things like microwaves and air conditioners all the time. If you're really concerned, feel the cord after a normal workout session. It may be warm but shouldn't be hot. Further, feel the blades on both cords and see if they're hot. Thinking about it, I'd make sure that the connection at the wall isn't too loose, either. It should take a solid push to insert and a similar tug to pull out.

The guy upthread using 200 feet (too long) of daisy-chained (insertion loss at each plug) cords for a chainsaw (high load device) is exactly the irresponsible behavior that compels manufacturers to say to never use extensions of any kind.
  #27  
Old 01-30-2017, 10:00 PM
K2500 K2500 is offline
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It's a four foot cord, no need for VD calculations or ambient considerations. A four foot cord for a treadmill mill? It'll work fine.
  #28  
Old 01-30-2017, 10:12 PM
watchwolf49 watchwolf49 is online now
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Originally Posted by jnglmassiv View Post
[snip] ... The guy upthread using 200 feet (too long) of daisy-chained (insertion loss at each plug) cords for a chainsaw (high load device) is exactly the irresponsible behavior that compels manufacturers to say to never use extensions of any kind.
Hey ... I'm a trained professional ... I knew exactly what I was doing ... it was just the one tree and I kept a sharp eye on matters ... everything else is within 100' and the 10 gauge cord works great ...

So, Mangosteen, just feel the cords after your workout ... if there's a heating problem you'll easily note it ... consider sliding the machine 4 feet towards the outlet as part of the workout ...
  #29  
Old 01-31-2017, 06:07 AM
Melbourne Melbourne is offline
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Originally Posted by Crafter_Man View Post
True, but it is usually only a problem with long extension cords.

Let's say you have a 120 V device that draws 10 A. And you want to power it with a 100 foot extension cord.

What gauge wire should the extension cord be? Since you're pulling 10 A, you can safely use a 12 gauge, 14 gauge, or 16 gauge extension cord. But as you mentioned, there is another issue that must be considered: voltage drop along the cord. Assuming T = 70 C and doing the math we discover:

Using a 12 gauge extension cord, the voltage at the load will be 116.2 V (3.2% low).
Using a 14 gauge extension cord, the voltage at the load will be 114.0 V (5.0% low).
Using a 16 gauge extension cord, the voltage at the load will be 110.4 V (8.0% low).

The threshold is 5%. So a 12 gauge extension cord would work fine. A 14 gauge extension cord would be marginal. A 16 gauge extension cord could be bad... the voltage would be 8% low at the device. The device could be damaged, depending on what it is.
If it's actually a 10A load for a 10A wire, then: Drawing 50 or 100A.

As I said, at startup motors often draw 5-10 times the rated current.

I would have guessed maybe a 500W motor, drawing 25 to 50 at startup.

Last edited by Melbourne; 01-31-2017 at 06:07 AM.
  #30  
Old 01-31-2017, 08:21 AM
ftg ftg is online now
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Again there's damage to the cord and then there's damage to the treadmill.

Feeling the cord tells you nothing about the extra strain that the treadmill motor is having for running at a reduced voltage.
  #31  
Old 02-02-2017, 11:43 PM
TokyoBayer TokyoBayer is online now
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Originally Posted by ftg View Post
Again there's damage to the cord and then there's damage to the treadmill.

Feeling the cord tells you nothing about the extra strain that the treadmill motor is having for running at a reduced voltage.
Electric motors are rated to be used with a tolerance of voltages.

If the OP has a good voltage from the wall, one additional connection and four feet isn't going to cause the voltage to drop significantly, and would have much less effect than somewhere which has a low voltage from the power company.
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