[JaLu]

I'm running power to a shed / barn. NOT in the city, so code is not a problem, but I DO have an NEC book. I need to go 300' -- and want to use best cost effective.

240v not needed, but I was considering 2/2/2 aluminum anyway.

Question: Is SEU rated... or at least acceptable.. for direct burial? There are places it says "Service Entrance Underground" -- but the Alcan Cable says their "Stabiloy" "Type SE style U" is "above ground service only"


What cable do I need to bury it ?

JaLu

[tkrussell]

Even thou you are not in a large city, I am sure the state you reside in has jurisdiction over any and all new electrical installations, and have adopted the National Electric Code, along with their own modifications.

SER cable is neither rated nor acceptable for direct burial.

300 feet is quite a distance to deliver 120 volt. 3- #2 al will work fine to keep the voltage drop at an acceptable level for a 20 amp load.

Any more load that that will cause the Vd to rise above the recommended 3%.

You can find a direct burial cable, 3 wire for hot ,neutral, and equipment ground, called URD.It is a cable assembly with all 3 or 4 wires twisted, ready to bury.

Or you can find aluminum wire with USE insulation. This will be individual wire, that you will need 600 feet of, cut into thirds, and lay the 3 wires in the trench.

Since this is residential, the trench needs to be a min of 18" deep. Best to lay a 6" bed of sand, then the cable, and then another 6" layer of sand. Very rocky soil conditions would need a large conduit as a sleeve for extra protection, and could allow for easy replacement or upgrades.

[JaLu]

Thanks TK,

There is a GraybaR ref that calls the SEU "Service Entry Underground"... and says the individual wires within -- they're XHHW rated, and the Code book calls them "wet" rated. I really don't know why they say that "underground". Not "direct burial" like it implies.

BUT, I did go out today and got 330' of Triplex URD cable. It's the "Stephens" type (aluminum) with 2 ea #2's and a #4. (pretty good price, $1.03 per foot. Sure beats the heck outa the biggest UF "Romex" I could find -- #6 copper at like $2 / ft.)

I have no need for 220/240 in my little barn, so will use just one leg.

It LOOKS like code for residential at or below 120v is only 12'. BUT, I'm going to get a little trencher and put it at least 24 to 30" deep.

Thanks again. J

[tkrussell]

I did not mention the 12" allowance for residential 20 amp 120 volt maximum circuit as it is only allowed under the condition that the entire circuit is GFI protected.

A GFI protecting a 300 foot circuit would experience nuisance trips due to the excessive capacitance.

[cochise7969]

I would just get it from this place, Burial Cable Low Voltage they have it all the telephone, fiber, data, coax. Nice

[stanfortyman]

Cochise,

A) What you link is all low voltage cable.

B) This thread is almost two years old.

[cochise7969]

I'm sorry it's the end of the day and I did not notice that. It's been a long day.

[JaLu]

Jeez ! Thanks guys. Im amazed that the thing still popped up a message telling me there is a reply after this time!

I DID run a 2/2/4 URD to my barn. 330' -- and the house is actually about 150' from the kettle -- i.e. the Transformer. I've got a 300a panel, but never really looked if they ran 000 or 0000 to the house. Works perfectly. I'm retired from a power company, but sort of debated if I should keep the ground and neutral separate.

I DID consider it as a sub-panel and just used one leg -- 120 hot on one #2 -- the Neut on the other #2 -- and tied to the main panel gnd with the #4.

I was using an old circ saw as I finished stuff up in the barn. It draws from 11 to 12 amp!

I've got an old Tripplet panel meter out of an ancient power plant -- about a 10 inch thing with 120v at center scale -- and the circ saw (after the normal inductive load start dip) will drop the normal voltage from 122 down to 119. AND that's with all the lights on -- five times 200w = a kw there, so that's 8 amp of lumens too!

Plenty good enough for guvm't work!

I DO wish I'd run a phone line in there though -- and one of those PEX water lines even.

Oh well. JL

[garys7]

I'm running power to a shed / barn. NOT in the city, so code is not a problem, but I DO have an NEC book. I need to go 300' -- and want to use best cost effective.

240v not needed, but I was considering 2/2/2 aluminum anyway.

Question: Is SEU rated ... or at least acceptable .. for direct burial? There are places it says "Service Entrance Underground" -- but the Alcan Cable says their "Stabiloy" "Type SE style U" is "above ground service only"


What cable do I need to bury it ?

JaLu

I would check with a local Electrical supply house. Home Depo carries some under ground wire but I've never seen larger than 12/2.

[stanfortyman]

I would check with a local Electrical supply house. Home Depo carries some under ground wire but i've never seen larger than 12/2.

Once again, the post you are quoting and answering is almost TWO years old, and on top of that the OP graciously just returned to explain how he already did the job.

[tkrussell]

There is no debate,

but sorta debated if I should keep the ground and neutral seperate.

Once a feeder leaves the Main Disconnecting Means, the neutral and equipment ground must always be separated.

You did separate them, so you are all set.