How come extension cords are rated different then home wiring?

[paperfist]

So 50' of Romex is called 12/2 with a ground wire. So 3 wires total...

http://www.homedepot.com/p/Romex-50-ft-12-2-Soild-SIMpull-CU-NM-B-Wire-28828222/202316374

But 50' a extension cord is called 12/3, but with 3 wires total...

http://www.homedepot.com/p/Husky-50...rd-with-Standard-Plug-747-123050H31/205377752

The extension cord is also only rated for 15 amps at 12 gauge vrs 20 amp for Romex at 12 gauge. Is that because one is a solid wire and the other a stranded wire?

 

[Blain]

Is that because one is a solid wire and the other a stranded wire?

Yes.
Are you considering a higher rated extension cord or just curious about the differences?

 

[herm0016]

the rating of the extension cord also takes into account the connections at each end and the insulation type. romex does not have connections and has better insulation generally.

 

[paperfist]

Yes.
Are you considering a higher rated extension cord or just curious about the differences?

I am looking into buying a 10 gauge, 100' extension cord for a generator. While researching them I just noticed the different way they label Romex and extension cords and it made me curious as to why.

 

[paperfist]

the rating of the extension cord also takes into account the connections at each end and the insulation type. romex does not have connections and has better insulation generally.

But still with Romex even though it has 3 wires, 1 being a ground it's labeled as 12/2 whereas with the extension cords the don't call out the ground as separate, but instead call it 12/3 wire.

 

[echo4747]

I am looking into buying a 10 gauge, 100' extension cord for a generator. While researching them I just noticed the different way they label Romex and extension cords and it made me curious as to why.

When selecting whatever cord you are going to use not only do you need the proper gauge you also need the appropriate insulation for the exposure/conditions the cord will be exposed to. Here is a handy guide to deciphering insulation types (i.e soow; sjo etc.)

S – Service, which means the portable cord has been rated for 600 volts.
J – Junior. Junior is short for Junior Service, which means the portable cord has been rated to 300 volts.
T – Thermoplastic. This refers to the material the cord jacket is made out of. Click here to learn more about Thermoplastic material. Thermoplastic material is light-duty and can be used as consumer grade portable cord.
E – Elastomer, which is short for Thermoplastic Elastomer. It also refers to the jacket material but it is different from plain Thermoplastic. Thermoplastic elastomer material is medium-duty and performs better in colder temperatures than thermoplastic. If a portable cord does not have a ‘T’ or an ‘E’, it is made of thermoset material, which makes it heavy-duty.
O – Oil Resistant, and the single ‘O’ means that only the outer jacket is oil resistant.
OO – Also Oil Resistant, but this time both the portable cord’s outer jacket and the insulation are oil resistant.
F – Fixture Wire, which means the cable is rated to 90°C.
P – Parallel. This cable is parallel-jacketed and is sometimes called “zip cord.”
H – Heater cord. This is used in UL cord types such as HSJ, HS, HSO, and HSJO.
V – Vacuum cord. “V” is the UL marking in parts like SVT and SVO. This is light-duty portable cord.
RD – Range or dryer cord. Product examples include SRD, SRDE, and SRDT cord.
W – Weather Resistant. Portable cord with a W means it’s approved as weather (sunlight, moisture, etc.) and water-resistant and can be used indoors or outdoors.

 

[Greenman]

It is a bit confusing. With romex they don't count the ground because it isn't normally a conductor. I'm not sure why the rules change with extension cord.

 

[Carson Dyle]

Speaking of extension cords:

I recently bought one for use in my garage that has an LED that lights at the socket end when the cord is plugged in. I can see how this would be handy on a job site or similar environment, but I'd prefer to leave the cord plugged in so I can just grab the socket end and go. With the little light, I'm inclined to unplug it each time I use it.

 

[stormkroe]

It's because cabtire (SO cable) can come in many different configurations and is sometimes used without a ground conductor connected. Because there is no wire purposed specifically for grounding/bonding (even though there is usually a green you can order any color combo), all conductors are counted.

 

[Red Squirrel]

I've been caught with this too. Bought 12/2 extension thinking it would have 2 current carrying conductors and a ground, nope, it's just two current carrying conductors. Doh.

 

[Raizinman]

I'm pretty tough on my extension cords; so I either make them myself (when I have time) or purchase at Harbor Freight. I find their cords pretty tough and the price very reasonable (always use a 20% off coupon) and get a free flashlight just for coming in!!

 

[Blain]

I am looking into buying a 10 gauge, 100' extension cord for a generator. While researching them I just noticed the different way they label Romex and extension cords and it made me curious as to why.

Wow, a 100' generator cord will cost you. Are you moving 120 or 240v?

 

[paperfist]

Wow, a 100' generator cord will cost you. Are you moving 120 or 240v?

Yeah big bucks no whammies! 120V. They are around $100 - $150. I think I've settled on a Flexzilla cord as I have their water hoses are they always uncoil flat and never tangle up.

I'm pretty tough on my extension cords; so I either make them myself (when I have time) or purchase at Harbor Freight. I find their cords pretty tough and the price very reasonable (always use a 20% off coupon) and get a free flashlight just for coming in!!

I see they have some great deals, but I'll never step foot in that store again. I returned a defective inverter generator and they charged me a $100 restocking fee.

It is a bit confusing. With romex they don't count the ground because it isn't normally a conductor. I'm not sure why the rules change with extension cord.

Makes sense. With Romex you can't really use the ground to carry electricity and it's not insulated. With an extension cord the ground has the same wire size and insulation that the other 2 wires have.

 

[echo4747]

Yeah big bucks no whammies! 120V. They are around $100 - $150. I think I've settled on a Flexzilla cord as I have their water hoses are they always uncoil flat and never tangle up.

out of curiosity, are you using this generator more as a jobsite unit ( for power tools) or to try and power a few items ( fridge, lights) in the event your home loses power?

 

[paperfist]

out of curiosity, are you using this generator more as a jobsite unit ( for power tools) or to try and power a few items ( fridge, lights) in the event your home loses power?

Jobsite.

 

[JEDIYoda]

I see they have some great deals, but I'll never step foot in that store again. I returned a defective inverter generator and they charged me a $100 restocking fee.

awwwwwww