Running service wire in crawl space AND underground

[justinae]

Hi all. I've been doing a lot of research and tried to answer this question myself but can't seem to get a clear answer.

First, I live in Portland, OR have a detached garage and a new 200 amp panel in the house. Feeder wiring will run in interior wall about 5', through the crawl space about 35', underground about 5', and then up the garage wall about 5'.

It seems I can run 2-2-2-4 service wire by itself in the walls and crawl space, but I am not allowed to run that in conduit in the ground, nor direct bury it (according to an electrician I talked to). A suggestion was made to run the 2-2-2-4 to the end of the crawl space and then using a jbox and split bolts, splice individual conductors and run them underground in PVC conduit.

The other option suggested is run PVC conduit from panel to panel and run individual conductors the whole way.

Is there an option that I'm missing? I'd rather not do the splicing, and it seems odd that there wouldn't be a bundled option that allows me to run underground a few feet.

Many thanks in advance.
Justin

 

[matt151617]

Correct... you cannot run SER in conduit. You need individual THWN wires; or the easier option is mobile home feeder. It is much easier to run SER to a box, transition to conduit, and then run conduit right into the subpanel.

 

[justinae]

Ok. That's good to know. It just seems odd that there isn't one type of wire that fits this very common scenario. Considering 3 #2 and 1 #4, and using split bolt connectors wrapped in what looks like a ton of tape, what size j box would you recommend? Can I use a non metal box to avoid having to ground it?

Thanks!

 

['04 Cummins]

Ok. That's good to know. It just seems odd that there isn't one type of wire that fits this very common scenario. Considering 3 #2 and 1 #4, and using split bolt connectors wrapped in what looks like a ton of tape, what size j box would you recommend? Can I use a non metal box to avoid having to ground it?

Thanks!

Use these connectors instead of split bolts:

Purchase them at any electrical supply house, sized for your wire. Split bolts require rubber splicing tape, then 3M #33. There is a proper way tape them, and many improper ways.

Use a PVC box w/ gasketed cover, say 8x8x4...


Personally, I would run conduit the entire way and use THWN conductors.

 

[justinae]

Those look way easier. What are they called?

I'll be pricing out conduit and individual conductors vs. spliced system.

Thanks

 

['04 Cummins]

NSI Polaris lugs. You would want part number IT-1/0.

Here's a Fleabay link for further details: http://www.ebay.com/itm/NSI-Polaris-IT-1-0-2-Port-Insulated-Wire-Connector-double-barrel-cable-connector-/110927543132?pt=LH_DefaultDomain_0&hash=item19d3cbfb5c

 

[pattenp]

I did the 2-2-2-4 SER from my main panel to a junction box and transitioned to 2-2-2-4 Mobile Home Feeder (MHF) which I ran in 2" PVC conduit to the panel in the detached garage. It is perfectly fine to do a splice. I used splice/reducers and used shrink tube to insulate. The Polaris connectors are very expensive.

 

['04 Cummins]

A quick look at prices puts the polaris lugs a bit more, but not by much when you factor in tape or heat shrink... Plus they're so damn easy. When I'm in a crawl space, I want easy, but that's just me

 

[brewchief]

A quick look at prices puts the polaris lugs a bit more, but not by much when you factor in tape or heat shrink... Plus they're so damn easy. When I'm in a crawl space, I want easy, but that's just me

It's not just you, I prefer easy if I can, I've used the Burndy version of the Polaris connectors and it's a lot easier then split bolts and tape.

If you can run conduit the whole way from panel to panel that's great, just remember no more then 360 degrees of bend before a pull point.

 

[justinae]

Yep I'm going to line out the pricing. For what it's worth, I'll report back what I find.

I wonder what you all have found easier. Running conduit in a crawl space and pulling through vs. running SER and a junction.

I've never run conduit before. It seems straight forward, but could you explain a "pull point"?

Thanks

 

[justinae]

It came out about $25 cheaper to run conduit all the way. At this point my question is about installation. I have post and beam construction with a crawl space, no rim joist so I don't think I have enough room for one of those long sweep 90s to get into the crawl. I plan to use 2" conduit. Is there an offset or some other kind of method to navigate the sill plate?

Thanks

 

[matt151617]

If a 90 bend won't fit then put a LB fitting. They're huge, but it'll allow you to make a sharp turn.

 

[pattenp]

These are conduit bodies such as LB's, LL's etc. and are used as pull points.

 

[ishiboo]

I did the 2-2-2-4 SER from my main panel to a junction box and transitioned to 2-2-2-4 Mobile Home Feeder (MHF) which I ran in 2" PVC conduit to the panel in the detached garage. It is perfectly fine to do a splice. I used splice/reducers and used shrink tube to insulate. The Polaris connectors are very expensive.

I used this to splice my service entrance, worked well. They have kits at the local BORG stores with the connectors and matching heat shrink.

 

[justinae]

These are conduit bodies such as LB's, LL's etc. and are used as pull points.

Can the #2 wires make that sharp snaking turn? So you pull it through the LB and then how do you pull through the next runs of conduit when they are not connected to the LB? Sorry if that is obvious.

Thanks!

 

[ishiboo]

Can the #2 wires make that sharp snaking turn? So you pull it through the LB and then how do you pull through the next runs of conduit when they are not connected to the LB? Sorry if that is obvious.

Thanks!

It's a pull point... you basically have to pull all you need to the LB, and then stuff the wire and start pulling it through the next "segment"... you won't be able to pull through multiple LBs. If you screw up, you can manually adjust at an LB though.

If the wire fits, anything can be done when you have accessible LBs and sweeping corners. The difficulty pulling is directly related to the degress of bends/etc., sharp corners (bad), use of lube, and the diameter of your conduit... as you'd expect.

Remember that the professionals use a pull line (NOT push the wire) and like any electrifying activity - use plenty of lube!

 

[justinae]

What kind of lube is best?

 

[matt151617]

What kind of lube is best?

They make lube specifically for pulling wires, available in Lowes/Home Depot. I used dish soap but it probably wasn't the best idea. But it did work.

 

[70z rex]

I just finished a jacuzzi install and i 2nd the use of polaris plugs, So simple and such a cleaner job for me anyway. I paid 16 dollars each at California Electric in El Cajon CA.

Rex

 

[justinae]

OK, I'm ready to run my wire. I decided to use the SER wire instead of conduit. Here is my plan.

Run 2-2-2-4 from inside 200 amp panel down wall and through crawl space.
Junction using Polaris plugs (or similar) and put in junction box
Transition to 1 1/2" PVC conduit
Run 1 1/2" PVC conduit the 4 feet from house to garage at 24" below ground level
Use LB fitting to get inside garage

This is where I'm confused. Since I'm running individual wires from the junction box in the crawl space, do I have to have conduit all the way to the panel in the garage? I'm assuming so. So how do I get conduit through the wall without it being ugly?

Install 100 amp breaker in 200 amp panel in house.

Any advice on the plan would be appreciated.

Thanks!

 

[pattenp]

Yes you have to use conduit all the way to the panel in the garage if using individual wires. Otherwise you'd have to do the same in the garage as you did in the house and use SER for the short run inside of the garage.

If you are using 2-2-2-4 aluminum then you can only over current protect it at 90 amps.

I can't help you on the ugly conduit issue.

 

[justinae]

Thanks Pattenp. Makes sense on the conduit to the panel. You're right about the 90 amp, I forgot that. The panel in the garage is 100 amp with main disconnect, but if I get a 90 amp breaker in the panel in the house I'm fine right?

 

[pattenp]

The panel in the garage with a 100A main disconnect is okay. The feeding breaker in the house main panel needs to be no more than 90A. Have you determined that you need the 90A? 60A may be all you really need and a 60A breaker is a lot cheaper than a 90A. Usually around $11-13 vs $40-45.

 

[justinae]

Yes I do only need 60 amp, but for another $25, plus the cost of wire, I think 90 will be good. I do run a woodshop and who knows what the next owner will want.

Thanks.

 

[justinae]

Can the panel be a stud bay over from where the conduit comes into the garage?

 

[pattenp]

The panel can be in any stud bay you want. The issue is getting the conduit to it with out butchering the studs.

 

[justinae]

I would only be going through one stud and it would be similar to running plumbing. I can always strap if I need to.

 

[wyliesdiesels]

There's one problem with drilling studs for conduit. Building code only allows u to drill out a certain amount of the stud, I believe 40%, for a load bearing wall and a little higher for a non load bearing wall. With a 1 1/2" ID conduit, you will need a hole somewhere between 1 3/4" and 2". On a 3 1/2" wide stud, that might be too big of a hole leaving only 3/4" on each side of the hole. Check your building/framing codes before you make a mess of your framing!

 

[justinae]

Yeah it's a 1 3/8" maximum hole for load bearing wall, which it is. Could I get by with 1 1/4" conduit instead of 1 1/2".

 

[justinae]

According to this calculator: http://www.electrician2.com/calculators/rf_calculator.html

I can use 1 1/4". It's a very short run of conduit so I think fishing won't be too much of a problem with a smaller conduit. I'll 2 long sweep 90s, one regular 90 and 1 LB.

 

[wyliesdiesels]

Yeah it's a 1 3/8" maximum hole for load bearing wall, which it is. Could I get by with 1 1/4" conduit instead of 1 1/2".

What size and number of conductors and what type of conduit are u using again? I will check my conduit fill charts!

 

[justinae]

(3) THHN #2 and (1) THHN #4

Thanks!

 

[wyliesdiesels]

The #4 is for EGC? Are u using cu or al? And how long is the total run? If the #4 is for the egc and the run isn't too long, then u can step that ground wire down to a #8 cu or #6 al with a 100amp branch circuit. That should save u some trouble when pulling!

 

[justinae]

I'm assuming EGC means the ground. Yes it is for that. Well I've got about 35' of 2-2-2-4 in the crawl and then it's individual wires in the conduit for about 10' to the panel.

It's all aluminum.

 

[justinae]

It's also going to ultimately be a 90 amp.

 

[wyliesdiesels]

Yes, egc= electrode grounding conductor and yes 1 1/4" sch 80 should work! If u haven't bought the #4 al yet, u can go with #6 al or #8 cu for your egc to make it a little easier!

 

[justinae]

Oh really? That's cool. Does it matter that I've got #4 in the SER cable?

 

[pattenp]

Oh really? That's cool. Does it matter that I've got #4 in the SER cable?

Personally I'd stick with the #4 for the equipment ground. The 3 #2 and 1 #4 will fit fine in 1 1/4 conduit. The aluminum should be compact conductors.

One thing you need to clarify is the wire type. You stated THHN, I assume it's dual rated with a THWN rating? Most wire of this type carries both ratings but I'd hate to see you use the wrong wire under ground.

 

[pattenp]

Also is 2-2-2-4 Mobile Home Feeder not available in your area? It may be cheaper than buying single THHN/THWN wire. The MHF is already assembled with a white marked neutral and a green ground where as the THHN/THWN you need to mark at the terminations.

 

[justinae]

Yes. I'm not 100% sure of which wire to use. There are tons of options. I stated THHN as it seems most common but planned to make sure I get the right one when it came time to order.

Do I need THWN?

What do you mean the aluminum should be compact conductors?

Thanks!