Emergency Need Truth About Direct Burial Cable

[Low IQ]

I bought me one of them new Chinese spas that are now available at such low prices. Not bad for the dough. I also bought a DIY guide on wiring it up from The Internet Electrician Online, a Canadian outfit (I am in the USA). The spa requires a 4-wire 50A service. Although I am leaving the final installation of the 50A breaker in the service panel to a licensed electrician, I am going to do most of the other work, and have my work double-checked when he hooks up the juice. I can't afford to have the electrician do everything or I would have bought an American made spa, right?

So, according to the Internet Electrician, I can use 6/3 w/ground direct burial cable for this job. (Not sure I trust his knowledge of USA rules). Here is what I plan to do: I will cut a hole in the wall near the service panel to the outside, and put a LB there and conduit down to the dirt on the side of my house. Then I will trench 18" deep over to the GFCI disconnet box, about 20 ft. Then there is a straight run from the disconnet to the spa of less than 15 ft. Conduit up to the box, and back down. In the trench I was going to lay the direct burial cable.

Now I seen posts in all kinds of forums that say I gotta use individual conductors inside rigid PVC conduit for this whole job including an insulated ground and that direct burial cable does not meet the NEC code. What is the real truth? Is direct burial cable really outlawed? Is it OK for any part of the job (like from the house to the disconnect box??) Everywhere I look on the Internet I get a totally different answer. Please, will a pro or anybody that knows what he's talking about set me straight with the real truth about the rules about wire in the dirt?

Yes, I do know that my local code here is exactly the same as the national code, I did confirm that some time ago. Right now I need to go to Home Depot and buy the supplies so I gotta know the truth. Oh, and yes I do know that the spa neutral goes to the GFCI breaker neutral, not ground bus, or the breaker will trip instantly when the juice is turned on. I do know that much, I'm not a total idiot. But I do totally appreciate advice from anybody.

I ask that God bless any responder in advance for their help.

[dave nh]

You should discuss your plans with the electrician before doing it, around here not to many electricians like to do only some of the job with there tag on the line. With that said, you shoud check if your town has adopted the NEC and if so what YEAR (important), also most towns have some guidelines for pool and spa installations. Not sure if you plan on pulling an electrical permit or not, but i would recommend it for liability/safety reasons.

With that said, to the best of my knowledge, underground feeder cable is not permitted for outdoor spa installations. Also, FYI, that stuff can be a pita to work with anyway. You are digging 18" rigid metallic conduit is cheap and you can re-run wires in the future if need be without digging it up.

Lastly, uf is a cable and is subject to derating per NEC, if for example your spa installation requires #6 cable (individual THNN in conduit), your cable size would likely need to be one size larger.

good luck with your install.

[Low IQ]

You should discuss your plans with the electrician before doing it, around here not to many electricians like to do only some of the job with there tag on the line. With that said, you shoud check if your town has adopted the NEC and if so what YEAR (important), also most towns have some guidelines for pool and spa installations. Not sure if you plan on pulling an electrical permit or not, but i would recommend it for liability/safety reasons.

With that said, to the best of my knowledge, underground feeder cable is not permitted for outdoor spa installations. Also, FYI, that stuff can be a pita to work with anyway. You are digging 18" rigid metallic conduit is cheap and you can re-run wires in the future if need be without digging it up.

Lastly, uf is a cable and is subject to derating per NEC, if for example your spa installation requires #6 cable (individual THNN in conduit), your cable size would likely need to be one size larger.

good luck with your install.

Dear Mr. Savant,

My electrician tole me "If I gotta teach ya, then I gotta charge ya." And Wilbur charges more for teachin' than doin'. Besides, he is fishing this week up at Lake Summit, so I am on my own to get the supplies and get this grunt work done before he limits out. You asked if my town adopted the latest NEC. Not sure, but my understanding is that the NEC trumps local code anyways. Town can go stricter, but not more lenient. Sorta like when there is a Federal law giving the death penalty for a serial killer, the local town can't say the penalty is just 10 days in the slammer because the poor guy had a unhappy childhood. Am I wrong (about the NEC I mean)?

Anyways, I appreciate the response. I ain't no genus, but like everybody else, I do understand why sheathed cable don't dissapate heat as good as individual conductors with air space around them, hence the possible de-rating for sheathed cable vs. wires in a raceway.

Is there anybody out there that can say for absolute sure if the NEC prohibits the use of direct burial cable for spa wiring, AND if this includes both the run from the breaker panel to the disconnect, as well as from the disconnect panel to the spa itself? -OR- is there a chance they prohibit the run to the spa, but allow direct burial cable from the house panel to the disconnect box??

[pdx_soaker]

What's wrong with using PVC just to be safe? It's not that expensive.

Make sure it runs through a spa breaker box close by (but not within reach of the tub itself)

[Low IQ]

Ain't pulling wires hard to do with a fishtape? How big a PVC for 4 #6 wires? Do I use solid copper wires or that stranded kind?

I know about the box. It gotta be at least 5 foot away so some idiot don't try to turn the spa off while in it and get fried (a lot of them did apparently).

[dave nh]

My electrician tole me "If I gotta teach ya, then I gotta charge ya." And Wilbur charges more for teachin' than doin'. Besides, he is fishing this week up at Lake Summit, so I am on my own to get the supplies and get this grunt work done before he limits out. You asked if my town adopted the latest NEC. Not sure, but my understanding is that the NEC trumps local code anyways. Town can go stricter, but not more lenient. Sorta like when there is a Federal law giving the death penalty for a serial killer, the local town can't say the penalty is just 10 days in the slammer because the poor guy had a unhappy childhood. Am I wrong?

Unfortunately he will probably charge you to come back if it is not up to local code or to his min. standard, i say better to try and work with him before you do the work even if it costs you a little more, but you know your situation best. At least around here local code rules, our town is still on 2002 NEC (thank god, did not have to deal with the new equipotential bonding requirements), plus they write there own exceptions to NEC or additions.

Like i said as far as uf cable you really need to know what edition of the code your town goes by as there are might be possible exceptions. For example i know the 2005 code requires an insulated ground to the spa, uf cable usually has a bare ground, no can do. There might be exceptions for branch circuits but feeder wires cannot be run by uf cable. Honestly, your best method all around imo is thnn in conduit. best of luck and i hope your install goes smooth.

[Dr. Spa]

Not sure, but my understanding is that the NEC trumps local code anyways. Town can go stricter, but not more lenient.

Not true at all. The NEC is not law, but recommendations, that an individual municipality can choose to adopt or not. While most municipalities do in fact adopt the NEC guidelines, they can be as far as 10 years behind the current NEC. e.g. the current NEC guidelines a municipality is following is from 1998 (actually, I once new a city that was 15 years behind).

[Low IQ]

Well that splains why they can ban the Marines down there in Frisco Bay. Well, anyways. I guess I will go with individual strands of wire and try to figger out how to use a fish tape. I sure hope it ain't hard to pull wires thru conduit. I guess I should get large PVC, but I don't know what size is best. One kid at Home Depot tole me one thing, they other guy something all different. One guy said solid copper wire, the other kid said it had to be the stranded kind. Before I make another trip down to Home Depot I got to gas up the '48 Ford pickup and hope that bald left front tire don't blow out. I should switch it out with the spare.

[Dr. Spa]

It's only the city of Berkeley.... And the "ban" is only on paper. If the marines want to go in, trust me, they will.

Stranded will pull MUCH easier. Give me the number and size of wires, and I can tell you size conduit required (conduit can only be filled 40%).

4 #8 or #6 wires needs 3/4" conduit, #4 requires 1"

Have a second person when you're pulling the wires to keep them separated and straight as they enter the conduit. No twisting or kinks. Easy as can be.

[Low IQ]

Dear Doctor,

Well, it is good to talk to somebody that knows his poop. I ain't gonna skrimp. I will go with all 4 wires (stranded kind then) of the #6 guage. Even the ground green one. Why not be safe. The cost of the 1" PVC is only a couple clams more than the 3/4". I gotta go around several 90 degree wide sweeps, so why not spend and get the 1" (I heard tell it is a lot easier to pull).

Should I slap some bacon fat on the wires before pulling them? I see Home Depot has one of them fish tape gizzmos for less than $20. I will get the neighbor kid to help me if I can pry the lazy bum away from his TV set for a few minutes. He's worthless as an accordian player at a deaf mute convention, but maybe he can learn somethin.

[Dr. Spa]

There's a special lube (water based) you could get, but I doubt it necessary with 1" conduit. If you want to save on the cost of the fish tape, you can probably pull the wire through with some heavy string. Ball up some paper to fit inside the PVC, tie the string to it, and suck it through with a shop vac. Tie it securely onto the wires (fold the wires back, making a loop and tape them together) and pull away.

[hotspringer]

Low IQ--

Attach one wire to the puller, then electrical tape the other three staggered so the whole works is tapered. Pull the wire BEFORE you bury the conduit. Much easier that way.

[Shaamus]

Something about this guy makes me think it's a joke.

[Dr. Spa]

Could it be due to where is IP number traces back too?

[Roger]

UF is exceptable, but some municipalitys don't allow it because if you dig it can be nicked easier than conduit. Imagine your suprise when you plant that bush and your shovel hits it!!...LOL

[Shaamus]

LowIQ should have known about IP logging and reverse DNS. I knew I recognized that used spa pic from somewhere.

[wireman]

You should dun put the bacon greezz on da wire wen you pullz it!

[wireman]

And on another note, there is nothing wrong with direct buried wire as long as min depth requirements are met.

[Low IQ]

Welp, I got all my goods from Home Depot, but its dark here now. Will start at sunup. I got an idea bout using a ping pong ball with the shp vac to suck a string thru the conduit, but dang it, the ball is a little too fat.

Last time I did wiring, it was knob n tube in the lean-to. Most o you young fellas wood not even know what that is.

[Shaamus]

Nebraska's state abbreviation is NE not NB. Thought you folks in WA would know that.

[Low IQ]

Nebraska's state abbreviation is NE not NB. Thought you folks in WA would know that.

May God bless you for catchin my topographical error son.

[dave nh]

And on another note, there is nothing wrong with direct buried wire as long as min depth requirements are met.

As long as it is not to supply an outdoor spa, see NEC 680.21 & 680.25. It may be acceptable in some localities that dont follow or except portions of the NEC.

[wireman]

Good point on that. In WA anything up to the hot tub disconnect is considered a feeder to a sub panel and any NEC approved wiring method is legal. The original poster seemed to think that any direct buried wire was illegal. I should have been more careful in my reply. Here's the thing. If you are doing this yourself you need to check with the local inspector and read any local codes. If you have a electrician do it make them get it inspected unless there is a reason not to.

In my opinion Sections I and II of 680 were not designed with portable hot tubs in mind ,such as most of us are using, but that's another discussion.

[Roger]

In my opinion Sections I and II of 680 were not designed with portable hot tubs in mind ,such as most of us are using, but that's another discussion.

I agree, and no matter how many times I read the codes I find nothing specific to portable hot tubs. So when I asked my local electrical inspector he said 6-3 UF was exceptable direct buried. So I would say your local municipality holds trump.

[Low IQ]

Welp, I got the ditch done. And by golly, I got a real big surprise diggin the last 2 feet. My spade hit something looked like red metal. Pulled out an old rusty Prince Albert pipe tabakky tin. Inside was about 2 dozen old Indian Head pennies oldest from 1879.

I am not messin with any direct buried cable. I seen it at Home Depot, and it looks real hard to work with and strip. The PCV pipe was cheap, and the old coins will go a long ways towards paying for a lot of this. I could get away with just about anything since my electrician's half-brother is the local electric inspector and I heard tell he sometimes looks the other way if you know what I mean. But I'm not taking any chances and doin it right anyways.