Crossing Stream with Electric Line

[CurlyDave]

I need to cross a winter creek with a 120 volt electric line.

The basic question is do I go over it, or under it?

The stream bed is 10-12 feet wide and at some times the water is 12" or so deep.

I can burry a plastic conduit up to about 6' deep if necessary, but I worry about any small leak causing it to fill with water.

Another possibility is to erect two poles and cross with an overhead line.

I also have some spare 20' sections of 6" steel well casing. I could cross with one of these with a vault at either end and run plastic conduit inside the steel casing. I would go underground to the two vaults. This actully seems like the safest and best way to me, but I also think it is totally non-standard and would not meet any building code known to western civilization. The steel well casing would be about 12" above the high water line.

Any other ideas? Direct burial cable?

Suggestions for which way to go?

 

[PAexcavator]

I would use direct burial cable and put it in either the steel or plastic as a conduit. If you use steel make sure the casing is grounded.

 

[vallyfarm]

I had the same problem several years ago, I put a T-post on either side of the stream to carry the wire well above the water. That must be around 10 yrs ago, and it's still there. Haven't had a problem yet. Easier than digging, and next to imposible to short out, but Martha Stewart might not like the view. Mike

 

[WhyNot]

I would just put in direct burial cable if it is deep enough I would think that the cable would be just as damp as if it was 3' under your yard. The conduit would be a waste unless you wanted it for peace of mind or to be able to replace the cable without having to dig up the stream bed. I say this because I have pulled a lot of cable through buried conduit and the conduit is always full of water. Seems as though there is no way to seal it good.

 

[randy41]

i think the conduit is not to keep the cable dry but to protect it from being cut by either abrasion or digging. so bury it in conduit.

 

[CurlyDave]

I have pulled a lot of cable through buried conduit and the conduit is always full of water. Seems as though there is no way to seal it good.

I have pretty much the same experience. The conduit seals well enough to keep water in, it just doesn't keep water out.

 

[tallyho8]

Either way, I would be sure to have the line protected with a gfi.

 

[EddieWalker]

Hey Dave,

I'd put it in conduit and bury it if I could. To keep moisture out, I'd fill the ends of the pipe with silicone before glueing them together. Even if you have perfect seals in conduit, the air that's in the lines will form condensation and you will have water puddle at the lowest point. Some guys just blow out the lines every know and then, but I'm not gonna do that myself.

I like to seal up each section of pipe knowing that the only condensation I'll have is what's in that length of conduit.

Eddie

 

[gordon21]

Use a GFI breaker AND GFI outlets at all locations at the end of the line. There's no sense killing anyone over $40 in parts. I would put the UG cable in conduit to protect it from abrasion, roots, etc.

 

[SPIKER]

I didn't see anything about this being a temp thing or perminate thing?

You can go either way but personally I wouldn't waste a lot of effort on 120 volt line unless this is something that HAS to run 24/7 365days a year. for simple light or to go to a gate or back to something used rarely I wouldn't bother burrying it...

mark M

 

[tommu56]

Dave
I would burry conduit and a spare 3 ft below bottom of stream bed fill trench back up with concrete holding conduit so it will get encased conduits 1 foot all aroud pipes use tw type wire.

Bring the runs to surface about 10 to 15 ft back from each bank of the stream put in a grade level pull box (Quartsite with open bottom work good) and make splice in each box that way when you have to trouble shoot it it will be just pull cover and check out.
When it gets washed out mabee it would come apart at splices and not rip out the rest of the system.

tommu56

 

[CurlyDave]

I didn't see anything about this being a temp thing or perminate thing?

Right now I am thinking of having the line energized 24/7.

The line would go to an RV pedestal to power my motorhome when we are not traveling in it, which would be most of the time. We have relatives with RVs, and when they come to visit we would move ours & let them park there.

Now, we have been parking it for years without power, but one of the advantages of moving to the country is having enough space to park the RV at home instead of in a storage yard.

 

[Buckeye_Jim]

Dave,

With the intended use now clear, you need to be careful about choosing the correct size of wire. I believe that you would be needing a 30 amp service to the RV, but you might call a RV park and ask which capacity of feed they use.

Several posters recomended direct buiral wire. You may not be able to get that in your required wire gauge. That would probably be 8 AWG stranded. This is something that the NEC will print tables to determine the correct size, based upon distance and that the cable is confined inside a conduit. A ground rod at RV side is also probably required. We have a supplier in Grass Valley who generally has prices for the power cables used for submersible pumps that is below the wholesale electrical dealers. That's A to Z Supply. I would recommend plastic 2" conduit with pull boxes on each side of the creek.

Good Luck,

Jim

 

[CurlyDave]

I was searching the internet for this and found a supplier last night.

I need about 100' of wire.

It looks to me like I can get 8-3 submersible pump wire for $3.04 /foot Submersible water well pump wire for use with submersible water well pumps. or I can get UF wire. If I got UF wire UF Direct Burial Wire Cable for underground power to your water well., which is quite a bit more expensive, it looks like the best deal there would be a 125 foot rool @ $4.41/foot.

Does anyone know why UF is so much more expensive than submersible pump wire?

It seems to me that if it goes in a conduit, which might end up full of water, submersible pump wire would be the better choice, but then logic does not always work in these areas.

Clearly I would also check local supply houses, but this gives me an idea of pricing.

 

[Dusty]

Can't say for certain, but I have used both, and the well wire is rubber jacketed and very pliable. The direct burial wire is very heavy plastic coated and extremely difficult to work with. You actually have to remove the roll from the box and then unroll it on the ground, being careful not to get any twists in it. If you twist it, it can be a bear to get it to straighten out and lay flat. I always put any underground wires in conduit on the assumption that I might have to replace it some time in the future. As for putting any electrical cable under water, I know that in CT, it generally isn't allowed. My guess is that the liability is the biggest factor, if there were a break and the water became electrified. I know of a housing development that has a stream that crosses the entrance road. The power is all underground except where they came out of the ground to an overhead pole and crossed the stream. Then they went underground again.
Dusty

 

[Dargo]

Does anyone know why UF is so much more expensive than submersible pump wire?

It seems to me that if it goes in a conduit, which might end up full of water, submersible pump wire would be the better choice, but then logic does not always work in these areas.

I used the direct bury UF wire when running electric to the island in my lake. It is in a conduit that is 1 piece and thick walled, but I assume that it will eventually be full of water. They used a boring machine to run the conduit. When I had the electrician out a few months later, we were surprised to find that there was no water at all in the conduit. Blowing high pressure air into the conduit only blew dust out on the island. Anyway, the electrician told me that, per code, I should use the UF wire in that conduit with GFI outlets. It's been there for 4 or 5 years now with no issue. Supposedly the UF wire will "never" have an issue even if my conduit fills with water. I couldn't tell you if there is any truth to that, but that's what I was told.

 

[Buckeye_Jim]

Dave,

I purchased last January #8 cable with 3 conductors plus a 4th #10 ground wire for my well, it's stranded, of course submersible, and cost $ .93 per foot. By far the best price I could find.

Jim

 

[MikeD74T]

Does anyone know why UF is so much more expensive than submersible pump wire? QUOTE]

UF wire has a tough outer layer that provides mechanical protection & ultraviolet light protection that well pump wire is not exposed to by virtue of being in a conduit and/or well casing. More insulation = more cost.
If you factor in conduit costs the UF would usually be cheaper, at least in the smaller sizes. MikeD74T

 

[midlf]

Pump cable is not code for anything but a pump. UF will pass code and, as stated is much more rugged. UF is waterproof. All the plastic used for protection is why it is so hard to work with.

 

[Buckeye_Jim]

Pump cable is not code for anything but a pump. UF will pass code and, as stated is much more rugged. UF is waterproof. All the plastic used for protection is why it is so hard to work with.

UF cable is tough to work with because it's a solid insulation incasing insulated wires. It also uses solid conductors. You use it for direct burial wire applications, but no need to use it in conduit. I am unaware that you could not use submersible pump cable in a conduit for a 100' run to bring service to an RV pedalestal. Before purchasing it for that application, I would call the local code authority to ask. The issues are voltage, current and temperature. By specifying one size larger (#8 instead of #10 for a 100' run on a 30 amp max load) you are giving more margin for heat.

Jim