# What's the best way to splice 1/0 cable?



## Randell Tarin (Jan 19, 2008)

I'm running a 100 AMP sub-panel 100' away from my main panel for an out building. I ran 1/0 direct burial 3-conductor cable to the site and allowed for enough cable to run up the wall into the new sub-panel.

For reasons to lengthy to mention, I must now locate the new panel an additional 20' away from it's intended location. What is the best way to extend this run?

1. A junction box with lugged connectors above ground? OR
2. Butt splices suitable for burial.

Thanks in advance for any recommendations.


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## 220/221 (Oct 9, 2007)

> 3-conductor cable


 

Uh oh......3 conductor with ground?

Don't splice below ground unless you have to. Water happens. Take into consideration the conditions, grade etc. If it AL wire, forget underground.


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## Randell Tarin (Jan 19, 2008)

That really doesn't answer my question. How do I actually splice the cable?
As to the ground, this is a sub-panel. It will have an isolated ground attached to a grounding rod.

I'm not sure what your issues are with aluminum, but underground aluminum is regularly used in my area.


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## jerryh3 (Dec 10, 2007)

Use big wire nuts. Just kidding. Relax for a second, he was just trying to get more information about the install. You say you're only running three wires to the building and that's a red flag that any electrician would question.


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## Andy in ATL (Aug 28, 2007)

Polaris taps.


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## Randell Tarin (Jan 19, 2008)

What are Polaris Taps?


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## Randell Tarin (Jan 19, 2008)

To Jerryh3: Must the sub panel be bonded to the main ground? I've been through this before when my main was wired. 

I live in a cabin in the woods. My meter base sits atop a 200 amp service panel with pass-through lugs. This panel is grounded with a rod. A 3-conductor wire then feeds a 200 AMP panel at the house 300 feet away. It has its own grounding rod. Wouldn't what I'm doing on this current project be the same? I plan to have an isolated equipment ground in the sub that's bonded to it's own grounding rod.


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## jerryh3 (Dec 10, 2007)

Randell Tarin said:


> What are Polaris Taps?


Polaris taps:
http://www.nsipolaris.com/pdf/polaris.pdf


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## J. V. (Jun 1, 2007)

Article 300.5 (E), Allows splices underground without the use of an enclosure. However, the splices must be approved for the location and installed according to the splice manufacturers recommendations.
Crimp butt splices are what I would use. Make sure you use the right crimp tool/setting and correct insulating method as described by the manufacturer. 
The other's are correct regarding the need for 4 wires. If you have two hots one neutral and one ground you are okay. If not, you can use an NEC exception making the sub panel a new service panel without the need for a another meter. (different subject).
Aluminum direct burial is also prevalent in my area for residential. What type of cable is this? It will marked on the jacket.

Andy.....Got any pics of the polaris taps. Never used them before. Thanks in advance....John

ps...Just saw the link. Go with Polaris. (Blue)


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## jerryh3 (Dec 10, 2007)

J. V. said:


> Article 300.5 (E), Allows splices underground without the use of an enclosure. However, the splices must be approved for the location and installed according to the splice manufacturers recommendations.
> Crimp butt splices are what I would use. Make sure you use the right crimp tool/setting and correct insulating method as described by the manufacturer.
> The other's are correct regarding the need for 4 wires. If you have two hots one neutral and one ground you are okay. If not, you can use an NEC exception making the sub panel a new service panel without the need for a another meter. (different subject).
> Aluminum direct burial is also prevalent in my area for residential. What type of cable is this? It will marked on the jacket.
> ...


Exceptions 250.32(b)(2)?


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## J. V. (Jun 1, 2007)

Randell. Looks like your cabin set up is the exception in the NEC for sub panels. They basically made both panels main service panels. I will have to look at the requirements to meet that standard. Someone here may have the requirements in their head.


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## Randell Tarin (Jan 19, 2008)

I had to go and look....

AWG 1/0 AL TYPE USE 2 80 MILS XLP INSULATION 600 VOLT
PHASE AAAAA DW


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## J. V. (Jun 1, 2007)

Thanks jerryh3.


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## nap (Dec 4, 2007)

as one poster stated, try to stay away from undeground splices. It is just trouble waiting to happen in the future. Even when done correctly, they tend to cause problems at times.

I would suggest not using polaris connectors unless you want to spend money. They are expensive and provide no real benefit for your situation. If available, I would use a crimp on splice but since this is a one time thing, obtaining the crimp tool may prevent this from being realistic. I am kind of cheap and would simply use split bolts if I could not use crimp on splices. Make it so your joints are in a j-box.


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## Randell Tarin (Jan 19, 2008)

Is there a j-box that has attached lugs for this purpose?


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## jerryh3 (Dec 10, 2007)

J. V. said:


> Thanks jerryh3.


Just checking. I had to reference that chapter a lot with my house.


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## nap (Dec 4, 2007)

You don't need lugs. A split bolt, polaris connector, or butt splice is all you need. 

I would prefer a permanent splice (crimp) is possible as you do not want to open this connection under any normal situation. 

With this, all you need is an wide open junction box (attached to a wall or such) that encloses the splices and then put a lid on it.


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## bigMikeB (May 31, 2007)

Why not just mount a disconnect on the outside of the building and go from there?


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## Randell Tarin (Jan 19, 2008)

I had thought about using a disconnect, but I wanted to put it underground, if possible, to provide a neater installation.

I like the idea of the Polaris Taps. If I can locate them, I'll probably go that route. I'm not so concerned about the cost as I am about the appearance. This is going to a guest cottage and I'd prefer not to have any exposed electrical systems. Kinda spoils the rustic-ness of the place.

Thanks everyone for your input!:thumbup:


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## jerryh3 (Dec 10, 2007)

Randell Tarin said:


> I had thought about using a disconnect, but I wanted to put it underground, if possible, to provide a neater installation.
> 
> I like the idea of the Polaris Taps. If I can locate them, I'll probably go that route. I'm not so concerned about the cost as I am about the appearance. This is going to a guest cottage and I'd prefer not to have any exposed electrical systems. Kinda spoils the rustic-ness of the place.
> 
> Thanks everyone for your input!:thumbup:


Is there metal plumbing run to it?


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## chris75 (Aug 25, 2007)

Randell Tarin said:


> I'm running a 100 AMP sub-panel 100' away from my main panel for an out building. I ran 1/0 direct burial 3-conductor cable to the site and allowed for enough cable to run up the wall into the new sub-panel.
> 
> For reasons to lengthy to mention, I must now locate the new panel an additional 20' away from it's intended location. What is the best way to extend this run?
> 
> ...


You need a disconnect to meet code anyways, so either put it on the outside of the building or inside at the nearest point of entrance of the conductors... nec 225.32


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## Randell Tarin (Jan 19, 2008)

Does the code require a specific disconnect or do I use some similar to an AC disconnect but rated at 100 amps?

Wouldn't the 100 AMP Main breaker serve as the disconnect?


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## nap (Dec 4, 2007)

> You need a disconnect to meet code anyways, so either put it on the outside of the building or inside at the nearest point of entrance of the conductors... nec 225.32


He has a farm stand installation so he can get away with 3 conductor feed. Personally I prefer a 4 wire install but hey, it is what it is. and yes, you need a disconnect (main breaker in the panel is acceptable)

The neutral and the ground and GEC system must all be bonded at the remote install when using a 3 wire feed. There must be a GEC system which can vary but it must include metal water pipe, if available, concrete encased electrode (foundation rebar) if it is a new building, and if you do not have the foundation ground, you need to supplement the water pipe with a ground rod (or similar electrode). 

Polaris connectors are also know by the manufacturer name NSI Industries. They mnaufacture Polaris connectors. IN my area they are now labled with the NSI name instead of Polaris.


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## chris75 (Aug 25, 2007)

nap said:


> He has a farm stand installation so he can get away with 3 conductor feed. Personally I prefer a 4 wire install but hey, it is what it is. and yes, you need a disconnect (main breaker in the panel is acceptable)



In 2008 it will be all 4 wire no matter what anyways..


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## nap (Dec 4, 2007)

chris75 said:


> In 2008 it will be all 4 wire no matter what anyways..


I presume you are referring to the '08 code. I am from Michigan so that means we won;t have to deal with that until somewhere around 2011, if they are typical in their actions.

I do understand there are some jurisdictions that have already accepted the '08 code though. Michigan tends to be a full cycle behind.


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## chris75 (Aug 25, 2007)

dont feel lonesome...


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## Randell Tarin (Jan 19, 2008)

nap said:


> ...The neutral and the ground and GEC system must all be bonded at the remote install when using a 3 wire feed. There must be a GEC system which can vary but it must include metal water pipe, if available, concrete encased electrode (foundation rebar) if it is a new building, and if you do not have the foundation ground, you need to supplement the water pipe with a ground rod (or similar electrode).


So, if I understand correctly, the neutral and ground are only isolated in the SUBPANEL when the MAIN and SUBPANEL are metallically bonded as in the case of a 4th wire or metallic conduit? That makes sense now. In the 3-wire install, the SUB essientally becomes a new MAIN panel.

I'll be driving two 8' electrodes into the ground and connecting this to the panel via a #6 bare copper wire. All my plumbing entering the structure is PVC and the foundation is post and beam.


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## Randell Tarin (Jan 19, 2008)

Thanks Stubbie! That approximates what I have with the exception of the neutral bar bonded to a water pipe. The soil around here has a high iron content and is fairly corrosive on iron pipe, so I have PVC running from the well and nowhere near the power drop.

To avoid cutting trees(we built in the woods), I elected to go with a 200 AMP mobile home drop with pass-through lugs. It has a grounding rod connected to it. Neutral and Ground are bonded in the box.

To my house, I ran 3 conductor wire underground and have it wired the way you have shown above. For my grounding electrodes, I have two 8 ft. rods in the ground about 25' apart. These are attached 2 ft. below ground by a #4 bare copper wire. 

The power company looked at it and said everything was copasetic. I ran #000 aluminum 3-conductor cable for a 300' run at 2' deep. I ran a voltmeter check on both the meter and the box at the house. At the meter, I was getting 244 VAC. I put a load on the other end and got a reading of 246 VAC. I would say I sized my conductor appropriately.


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## Randell Tarin (Jan 19, 2008)

Found the Polaris connectors. You guys were right...super easy. I put the last 15 feet of the run in 2" PVC and have this connected to a PVC Junction box. I used the connectors, sealed the lid, and presto, a successful splice.


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## 220/221 (Oct 9, 2007)

If your PVC box is below grade you might want to drill some weep holes in the bottom.. Water WILL get in (condensation....thru the open end of the 15" piece....etc) and you want to let it out.

AL wire does NOT like water.


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## Randell Tarin (Jan 19, 2008)

Thanks for the heads up. I haven't buried it yet. It's in sand, so the surrounding soil should drain away any moisture quickly.

The Polaris connectors are rated to directly go in the ground, so with the added protection of the junction box, I should be O.K.


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