3000W Chinese Gensets Info.

TKMJ wrote:
Now lets look at cord coding. The type of cord stampped on the jacket. Each letter of the code means something different. Most standard extention cords are coded type SJW.
"S" means standard rubber or plastic cord jacket.
"J" means junior grade. The jacket is thin and should not be left outside in use for long periods of time. The jacket can crack from heat and sunlight. It is also easy to nick and will not take much abuse.
"W" means simple enough "waterproof"
Now there is another code letters "O"
"O" means outdoor use.
Being a certified master electrician and the owner of TKMJ Productions a sound production and audio recording company, all of my cords are marked "SOW" (standard, outdoor, waterproof) This is the coding you want on your cords. "SOW" cords are very heavy with thick insulation and a very heavy jacket. They can take a lot of abuse of cars and trucks running over them. You can pull them thru gravel parking lots without worry. They are also very heavy in weight. About the only thing you can't do to them is run them over with your lawn mower.

Stay away from any cord for your RV or genset that has the "J" marking unless it is used in an area that will not have traffic walking on it. Type "J" cords are "very light duty" and do not take a lot of abuse.

So lets get back to your cord in the backyard. I would recomend a "SOW" cord if you plan on letting it set outside for long periods of time (longer then a week) or a "SO" type cord if you are going to run the cord out when the power fails and put it away when power is restored. "SO" cord can set outside for a few days without a worry.

Extremely good information on cord types. Thank you.

But, I feel you are giving the "J" designation cords a bad rap. Please allow me to add to the explaination.

The first letter, in this case "S", actually refers to a portable appliance cord with a rubber outer jacket, stranded conductors, cotton between wire and insulation, and jute fillers.

After the first "S" you may encounter one or more letters.

Following the "S" the letter "J" (like SJ) indicates medium duty with (some type of) outer rubber jacket. It is good stuff, UV resistant and will last a long time. It is not good if you are going to drive over it or leave it outdoors on a l*o*n*g term basis.

SV type cord is for light service. Not advised for your project. This is the one you should stay away from!

The "O" suffix indicates a neoprene cover. Really tough stuff, oil resistant, highly UV resistant. Stays flexible at cold temps.

The "W" indicates wet applications. i.e. Outdoor in rain and snow.

Some brands may omit the "J" giving a designation of SOW (like TKMJ uses). As suggested, this would be a good choice for your application. Do not be shocked at the per foot price. It ain't cheap!

For more on cord chacteristics you might want to cruise General Cable's Catalog.