expiredOhsighrus posted Today 12:59 PM
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Item 1 of 2
expiredOhsighrus posted Today 12:59 PM
KTMC 15' 16AWG PVC Vinyl Outdoor Extension Cord
$4.95
$9.90
50% offAmazon
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Deal Details
KT-MC via Amazon has KTMC 15' 16AWG PVC Vinyl Outdoor Extension Cord on sale for $4.95. Shipping is free with Prime or on $35+ orders.
Thanks to Community Member Ohsighrus for sharing this deal.
Thanks to Community Member Ohsighrus for sharing this deal.
Editor's Notes
Written by citan359 | Staff- About this Deal:
- Limited time deal, while supplies last.
- About this Product:
- 100% failure-free warranty replacement
- Rated 4.7 out of 5 stars at Amazon based on over 520 customer reviews.
- About this Store:
- Don't have Amazon Prime? Students can get a free 6-Month Amazon Prime trial with free 2-day shipping, unlimited video streaming & more.
- If you're not a student, there's also a free 1-Month Amazon Prime trial available.
- Seller KT-MC has a 100% positive feedback rating in the last 12 months, with over 195 Lifetime feedback.
Product Info
Community Notes
About the Poster
Deal Details
Product Info
Community Notes
About the Poster
KT-MC via Amazon has KTMC 15' 16AWG PVC Vinyl Outdoor Extension Cord on sale for $4.95. Shipping is free with Prime or on $35+ orders.
Thanks to Community Member Ohsighrus for sharing this deal.
Thanks to Community Member Ohsighrus for sharing this deal.
Editor's Notes
Written by citan359 | Staff- About this Deal:
- Limited time deal, while supplies last.
- About this Product:
- 100% failure-free warranty replacement
- Rated 4.7 out of 5 stars at Amazon based on over 520 customer reviews.
- About this Store:
- Don't have Amazon Prime? Students can get a free 6-Month Amazon Prime trial with free 2-day shipping, unlimited video streaming & more.
- If you're not a student, there's also a free 1-Month Amazon Prime trial available.
- Seller KT-MC has a 100% positive feedback rating in the last 12 months, with over 195 Lifetime feedback.
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Top Comments
Resistance is dependent on main 3 factors…resistivity of the conduit material, length of the conduit, and cross sectional area of the conduit.
Power dissipation is current squared multiplied by resistance.
Conduits can be considered only a small portion of resistance where the appliance determines the resistance and thus current given essentially static voltage.
V= I x R
Power = I x V
Power = I^2 x R (refactored)
Here's where it gets interesting. Say you have a toaster set to low, then turn it to high…say that halves the resistance inside the toaster leaving the cord resistance static, which essentially halves the circuit resistance and doubles the current through the circuit. This would essentially double the power at the same voltage flowing through the circuit and dissipated within the appliance BUT the resistance of the conduit between the voltage source and appliance remained static while current through essentially doubled, so while the appliance had a 2x power increase the conduit saw a 4x increase in power dissipation, where the power dissipation in the conduit (extension cord) is dependent mostly on its resistance as the current is essentially determined by the appliance.
Conduit resistance = (resistivity x length) / cross sectional area
Thus, all else equal, conduits that are longer, of smaller diameter, and which use material of lower conductivity (higher resistivity) will have have higher resistance and dissipate more total power (heat up more) given the same current.
However at the same gauge (diameter) and resistivity (conductor material) a shorter cable like a dollar store cable has lower resistance and will dissipate less total energy BUT the same energy per unit length…so temperature increase of the extension cord is resistance dependent…thus if a cord feels cooler then it is very likely lower resistance per unit length.
Aluminum is a good conductor, and often used for its lower cost and light weight in industrial applications at high voltages as it has less resistance per unit weight than copper. However in small conduits, it's inferior. Weight and usually cost isn't a huge issue, it exhibits higher stress fatigue than copper meaning it's less durable being bent often, and will result in greater losses and more heating at the same diameter and length. This is why solid copper cables are superior to aluminum or copper clad aluminum for home extension cords. In fact at longer lengths and running appliances at high current, a large diameter solid copper extension cord can notably decrease power consumption versus a narrower gauge aluminum cord, and lower cost of operation while increasing safety with higher durability as well…such as when used to power a space heater.
* many cheap cords will use narrow conductors but thick insulation to make it feel more substantial.
* * many electrical cords that DON'T say solid copper very likely aren't…and if the plug isn't copper colored it almost certainly isn't a copper cord, but if the plug is copper colored it may still be only copper plated.
Ok I'm done ranting
We are all in this together!
18 Comments
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It says 33% bigger core, I presume this implies larger diameter, which implies bigger current threshold... Yet, it is is rated at 'up to 13A'. My tiny extension cord from Dollar Tree is rated at 15A and it handles almost 1800W without getting noticeably hot. What am I missing here?
Our community has rated this post as helpful. If you agree, why not thank redaurora
That said at this price with the size of my christmas display I am in for a few
Our community has rated this post as helpful. If you agree, why not thank luckydog97
It says 33% bigger core, I presume this implies larger diameter, which implies bigger current threshold... Yet, it is is rated at 'up to 13A'. My tiny extension cord from Dollar Tree is rated at 15A and it handles almost 1800W without getting noticeably hot. What am I missing here?
Resistance is dependent on main 3 factors…resistivity of the conduit material, length of the conduit, and cross sectional area of the conduit.
Power dissipation is current squared multiplied by resistance.
Conduits can be considered only a small portion of resistance where the appliance determines the resistance and thus current given essentially static voltage.
V= I x R
Power = I x V
Power = I^2 x R (refactored)
Here's where it gets interesting. Say you have a toaster set to low, then turn it to high…say that halves the resistance inside the toaster leaving the cord resistance static, which essentially halves the circuit resistance and doubles the current through the circuit. This would essentially double the power at the same voltage flowing through the circuit and dissipated within the appliance BUT the resistance of the conduit between the voltage source and appliance remained static while current through essentially doubled, so while the appliance had a 2x power increase the conduit saw a 4x increase in power dissipation, where the power dissipation in the conduit (extension cord) is dependent mostly on its resistance as the current is essentially determined by the appliance.
Conduit resistance = (resistivity x length) / cross sectional area
Thus, all else equal, conduits that are longer, of smaller diameter, and which use material of lower conductivity (higher resistivity) will have have higher resistance and dissipate more total power (heat up more) given the same current.
However at the same gauge (diameter) and resistivity (conductor material) a shorter cable like a dollar store cable has lower resistance and will dissipate less total energy BUT the same energy per unit length…so temperature increase of the extension cord is resistance dependent…thus if a cord feels cooler then it is very likely lower resistance per unit length.
Aluminum is a good conductor, and often used for its lower cost and light weight in industrial applications at high voltages as it has less resistance per unit weight than copper. However in small conduits, it's inferior. Weight and usually cost isn't a huge issue, it exhibits higher stress fatigue than copper meaning it's less durable being bent often, and will result in greater losses and more heating at the same diameter and length. This is why solid copper cables are superior to aluminum or copper clad aluminum for home extension cords. In fact at longer lengths and running appliances at high current, a large diameter solid copper extension cord can notably decrease power consumption versus a narrower gauge aluminum cord, and lower cost of operation while increasing safety with higher durability as well…such as when used to power a space heater.
* many cheap cords will use narrow conductors but thick insulation to make it feel more substantial.
* * many electrical cords that DON'T say solid copper very likely aren't…and if the plug isn't copper colored it almost certainly isn't a copper cord, but if the plug is copper colored it may still be only copper plated.
Ok I'm done ranting
Sign up for a Slickdeals account to remove this ad.
Are there any EE majors here that can shed some light on this:
It says 33% bigger core, I presume this implies larger diameter, which implies bigger current threshold... Yet, it is is rated at 'up to 13A'. My tiny extension cord from Dollar Tree is rated at 15A and it handles almost 1800W without getting noticeably hot. What am I missing here?
Not an engineer but am pre med with some formal applied physics training.
Resistance is dependent on main 3 factors…resistivity of the conduit material, length of the conduit, and cross sectional area of the conduit.
Power dissipation is current squared multiplied by resistance.
Conduits can be considered only a small portion of resistance where the appliance determines the resistance and thus current given essentially static voltage.
V= I x R
Power = I x V
Power = I^2 x R (refactored)
Here's where it gets interesting. Say you have a toaster set to low, then turn it to high…say that halves the resistance inside the toaster leaving the cord resistance static, which essentially halves the circuit resistance and doubles the current through the circuit. This would essentially double the power at the same voltage flowing through the circuit and dissipated within the appliance BUT the resistance of the conduit between the voltage source and appliance remained static while current through essentially doubled, so while the appliance had a 2x power increase the conduit saw a 4x increase in power dissipation, where the power dissipation in the conduit (extension cord) is dependent mostly on its resistance as the current is essentially determined by the appliance.
Conduit resistance = (resistivity x length) / cross sectional area
Thus, all else equal, conduits that are longer, of smaller diameter, and which use material of lower conductivity (higher resistivity) will have have higher resistance and dissipate more total power (heat up more) given the same current.
However at the same gauge (diameter) and resistivity (conductor material) a shorter cable like a dollar store cable has lower resistance and will dissipate less total energy BUT the same energy per unit length…so temperature increase of the extension cord is resistance dependent…thus if a cord feels cooler then it is very likely lower resistance per unit length.
Aluminum is a good conductor, and often used for its lower cost and light weight in industrial applications at high voltages as it has less resistance per unit weight than copper. However in small conduits, it's inferior. Weight and usually cost isn't a huge issue, it exhibits higher stress fatigue than copper meaning it's less durable being bent often, and will result in greater losses and more heating at the same diameter and length. This is why solid copper cables are superior to aluminum or copper clad aluminum for home extension cords. In fact at longer lengths and running appliances at high current, a large diameter solid copper extension cord can notably decrease power consumption versus a narrower gauge aluminum cord, and lower cost of operation while increasing safety with higher durability as well…such as when used to power a space heater.
* many cheap cords will use narrow conductors but thick insulation to make it feel more substantial.
* * many electrical cords that DON'T say solid copper very likely aren't…and if the plug isn't copper colored it almost certainly isn't a copper cord, but if the plug is copper colored it may still be only copper plated.
Ok I'm done ranting [IMG]https://static.slickdealscdn.com/images/smilies/emot-LMAO.gif[/IMG]
(Actually, I 'liked' your explanation - impressively done.)
Resistance is dependent on main 3 factors…resistivity of the conduit material, length of the conduit, and cross sectional area of the conduit.
Power dissipation is current squared multiplied by resistance.
Conduits can be considered only a small portion of resistance where the appliance determines the resistance and thus current given essentially static voltage.
V= I x R
Power = I x V
Power = I^2 x R (refactored)
Here's where it gets interesting. Say you have a toaster set to low, then turn it to high…say that halves the resistance inside the toaster leaving the cord resistance static, which essentially halves the circuit resistance and doubles the current through the circuit. This would essentially double the power at the same voltage flowing through the circuit and dissipated within the appliance BUT the resistance of the conduit between the voltage source and appliance remained static while current through essentially doubled, so while the appliance had a 2x power increase the conduit saw a 4x increase in power dissipation, where the power dissipation in the conduit (extension cord) is dependent mostly on its resistance as the current is essentially determined by the appliance.
Conduit resistance = (resistivity x length) / cross sectional area
Thus, all else equal, conduits that are longer, of smaller diameter, and which use material of lower conductivity (higher resistivity) will have have higher resistance and dissipate more total power (heat up more) given the same current.
However at the same gauge (diameter) and resistivity (conductor material) a shorter cable like a dollar store cable has lower resistance and will dissipate less total energy BUT the same energy per unit length…so temperature increase of the extension cord is resistance dependent…thus if a cord feels cooler then it is very likely lower resistance per unit length.
Aluminum is a good conductor, and often used for its lower cost and light weight in industrial applications at high voltages as it has less resistance per unit weight than copper. However in small conduits, it's inferior. Weight and usually cost isn't a huge issue, it exhibits higher stress fatigue than copper meaning it's less durable being bent often, and will result in greater losses and more heating at the same diameter and length. This is why solid copper cables are superior to aluminum or copper clad aluminum for home extension cords. In fact at longer lengths and running appliances at high current, a large diameter solid copper extension cord can notably decrease power consumption versus a narrower gauge aluminum cord, and lower cost of operation while increasing safety with higher durability as well…such as when used to power a space heater.
* many cheap cords will use narrow conductors but thick insulation to make it feel more substantial.
* * many electrical cords that DON'T say solid copper very likely aren't…and if the plug isn't copper colored it almost certainly isn't a copper cord, but if the plug is copper colored it may still be only copper plated.
Ok I'm done ranting
(Actually, I 'liked' your explanation - impressively done.)
We are all in this together!
Sign up for a Slickdeals account to remove this ad.
We are all in this together!
Leave a Comment