Underground electrical splice

[mkirsch]

I have two outbuildings, a 10x15 shed and a 24x32 pole barn.

The previous owner buried a #6 cable from the house to the small shed, about 200'. Later on when he built the pole barn, he buried a #10 wire between the small shed and the pole barn, about 30 feet away.

I want to tear down the small shed and run the #6 all the way to the pole barn.

Is there a way to splice on to the existing buried cable and extend it, keeping the splice safely buried, that isn't a code violation?
 

[Pete_5959]

MK,
We had similar issue at our hunting camp a few years ago. I stripped and twisted two inch long and soldered. Used brush on tape from lowes. then individually wrapped with black tape. Over black tape used stretch 3M tape and covered with scotch coat. zero issues to date. I would bet the only code solution is going to bring the splice point above ground in a box.....
 

[buickanddeere]

Only way is to bring the cable to the surface and connect to
terminal blocks inside a weather resistant enclosure.
An underground splice is spelled " Boom- Sizzle".
It's difficult enough to keep non-spliced cable from shorting
out underground.
Better yet are those power pedistals with a breaker box and
spaces for receptacles. To use as a junction box in the yard.
Equipment and vehicles that are not parked inside can be
plugged in for winter starts. Not a bad place for a welder plug
either. A lot less smoke and heat when welding outside.
40amp load at the shed would be lots with #6 and that
distance.
Neutral and ground shall not be bonded at the junction box
or at the shed. The shed and junction box need ground rods
connected to only the ground wire/ground lug.
 

[Paul from MI]

Check with a good electrical supply co. I think there are UL approved underground splice kits available, might be a bit pricey. If not, think about putting up a pole with a mercury light & set a junction box on it.
 

[4010guy]

Get a splice kit and clamp it together or whatever and then just put a heat shrink over it...not like new but should work..
 

[jackinok]

underground cable can be spliced/repaired. but it takes special connectors and things to keep them watertight.what we used to do was use a underground waterproof crimp connector that used a silicone type paste to keep water out.wrap that in rubber tape,cover that in plastic tape, cover the whole works with a liquid tape type coating.
 

[onedeere37]

Get a ul listed splice kit and what i call a flower pot Witch is
an access panel to get the splice kit the pot sits flush with
the ground u can't really see it unless your looking for it
 

[Zachary Hoyt]

I got a kit from ebay with a connector with set screws and a really
heavy duty shrink tube to go over it. It has worked fine so far for
me.
Zach
 

[MisterT]

I wouldn't even attempt any kind of splice because that #6 is too small anyway. Needs to be minimum #2 for that distance.
 

[John T]

Check with your local electrical supply house, ifffffff thay have a UL approved underground splice kit, go for it butttttttttt I agree with the others, instead of splicing underground, Id at least consider bringing it above surface and splice in a weatherproof junction box. Your money your choice.

If the chart I looked at is correct, if thats No 6 copper wire and you pull 40 amps the voltage drop would be 6.5 volts !!!!!!!!!

Under older codes, for 120/240 volt single phase three wire service to a remote outbuilding you could get by with only three wires (L1 L2 Neutral), but nowadays most jurisdictions require four wires (L1 L2 Neutral Equipment Ground)

You may want to check with local authority if any exists where you live or your utility provider OR DO IT AND CHECK WITH NOBODY, YOUR CHOICE NONE OF OURS HERE.

Of course, the barns electrical service requires proper earth grounding (driven rod or rods, metallic utility pipes etc) REGARDLESS if three of four wire.

Post back any questions, check your local electrical supplier, consider checking with your utility provider or local authority, insure the barns service is earth grounded, take a look at your loads and see if voltage drop becomes an issue with 200 feet of No 6 wire???

Check to see how Billy Bob and Bubba would wire it???

John T
 

[Kirk Grau]

I only have a single experience with a UG splice, but it only held up for 2-3 years. This was a heated waterer in a pasture that my wife wanted moved (most of her reasons were good, but it did make for some work.) Spliced into the existing feed to the waterer. Maybe 2 years later have a dead short somewhere in the line. Can't say for certain it was the splice, but seems likely to me. Abandoned that branch circuit and installed new.

I like the idea of setting a pole light and haveing a box to make the splice, but that might not fit into your plans. As others have noted, you don't have an abundance of capacity in the existing wire, but if you are only looking for a few lights and a convenience receptacle or 2 it should be fine.

Good Luck whatever you decide,

Kirk
 

[RMinVa]

Made a lot of splices over the years and some
underground. I'd make the splice connection with
split bolts sized for the wire unless you have
access to lugs and a crimper. Keep it clean. After
each split bolt connection is made use Scotch
Varnished Cambric Tape and cover all the exposed
area and up the insulation about 2 inches and at
least 3 wraps. Keep it clean. Then use Scotch
Linerless Rubber Splicing Tape. This tape is made
to stretch as it's being applied. Cut each piece
about 5 inches long and stretch as applied to
cover all the area with at least 2 complete wraps
and extend up the insulation past the Cambric
about 1 inch. Keep it clean. Then apply Scotch
Super 33+ Vinyl Electrical Tape. Tape over the
linerless with 3 full wraps and up the insulation
another inch past the linerless.

Don't settle for other brands of tape. This is
the best I know of and have used it for over 25
years. The linerless will become a ball of rubber
and seals really good if applied proper. The
Cambric is used basically so you can get all that
tape off the connection if need be later. If you
don't use the Cambric and have to get back in that
connection later you'll wish you had used it. The
linerless is really hard to cut once it's applied.
It has to be cut to be removed. If you have to cut
some you can most of the time feel when the blade
goes through the Cambric. Then you can use channel
lock pliers and roll the tape wad off.

Use heat shrink over all that.
 

[John T]

Yearssssssss ago I made such a similar splice and had even more coats of epoxy and silicone and tape etc etc and its never went bad yet KNOCK ON WOOD LOL

John T
 

[Glen SW Wi]

Check with your local hardware store. Ace used to have an underground connection sealing kit. It consisted of a plastic cover that went over the splice and then was filled with a insulating material. Something like liquid electrical tape.

When I worked offshore in the Gulf, we used a similar system to seal the splice for the subsea pumps. Never had any problem with anything shorting out. These pumps were 25 ft under the surface.
 

[RMinVa]

Many years back I had one to blow out. Guess that was my classroom. Working in heavy industry you throw code out the door at times to get back running. There's some old repairs that we never got back to and are still good today. I wouldn't dare try that with 4160 but have several times on 480.

I've always been amazed at the spray paint insulation we use now on 4160. Course that's all in a dry J-box and I still don't trust the stuff completely and use the other wraps with it. But it works and with 4160 I use anything that helps keep that stuff in the insulation.

Few years back we upgraded to some mining cable running 1000 hp motors that moved in a aligator tract as the carriage made it's stroke. This cable had an extra layer if graphite inside and the guys on night shift didn't see it printed on that wrap. It was left in there right against the lugs. Started that big boy up and by the 4th stage of the start cycle it blew the door off that 4'x4' 2' deep junction box. Hinges and all. Some more of that true classroom work. LOL 4160 takes time to prep. We don't rush that work at all.