#2ga Aluminum in PVC?

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Old 01-31-19, 08:07 PM
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#2ga Aluminum in PVC?

I am replacing a small subpanel in a outbuilding with a 100amp Eaton and using #2 aluminum , 2 conductor and 1 neutral bare.
The run is about 25-30 feet may I run the 2 wires in a PVC conduit so it will not be exposed?
The run will be mostly attached to the ceiling (8' tall wafer board) of one shop to another adjacent building using PVC all the way.
Is this possible and not out of code.
will use a bare copper for a ground rod but on in this conduit.
Thank you
Ron
 
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Old 01-31-19, 08:25 PM
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By code..... a 120/240v sub panel requires two hots, a neutral and a ground.
It sounds like you are sleeving an aluminum cable underground in PVC. Not only does the cable need to be 3+1 conductors..... it must be rated for underground use.
 
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Old 01-31-19, 08:37 PM
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No, nothing underground , only on ceiling if shop #1 into ceiling of shop #2.
Using #2 ga. aluminum with 2 insulated conductors and one bare neutral.
The copper ground will NOT be sleeved in the PVC conduit it will take a different route to ground.
Only need to know if I can sleeve the 3 aluminum wires together in a PVC conduit from one panel to the other and attach to the ceilings of the shops.
Plan on 1 1/4" PVC?
Ron
 
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Old 01-31-19, 08:45 PM
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2 conductor and 1 neutral bare
You need three insulated (H-H-N) and a ground.
Only need to know if I can sleeve the 3 aluminum wires together in a PVC conduit from one panel to the other
No, because you need four wires not three (hot-hot-neutral-EGC ground) as PJMax wrote:
the cable need to be 3+1 conductors
 
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Old 01-31-19, 08:50 PM
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I can only endorse a code accepted method. A sub panel requires 4 wires between it and the panel it's being connected to. A ground rod is not a grounding method. It is for lightning protection and is required if the shop is a separate building. If the shop is attached.... no ground rod is needed.
 
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Old 01-31-19, 08:54 PM
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In addition, all conductors need to run in the same.cable.or.raceway.
 
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Old 01-31-19, 09:01 PM
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Now that you bring it up, the shops are only connected by a piece of 1" rigid conduit of about 3'. nothing else touches the two shops, they are about 3 feet apart.
So I need another length of #2 ga. aluminum to put with my other 2insulated hots and use the #2 bare aluminum as the ground and not a neutral?
Put them 4 thru a 1 1/4" electrical PVC?
 
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Old 01-31-19, 10:06 PM
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So I need another length of #2 ga. aluminum to put with my other 2insulated hots and use the #2 bare aluminum as the ground and not a neutral?
Yes.
Put them 4 thru a 1 1/4" electrical PVC?
Yes,

Note normally you only need #6 for ground but oversize is okay.
 
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Old 02-01-19, 05:50 AM
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Thanks Ray, the 3 conductors ,and a single stranded bare are all #2 Aluminum. None are in a sheath, I think the guy I bought it from stated it was called Triple AC ? and I need to add a #6 as a ground?
put all 5 of these in a 1 1/4" grey PVC from panel to panel running along an interior wall and ceilings about 25 feet.
 
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Old 02-01-19, 07:31 AM
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It sounds to me the wire you have is aerial service drop cable. The 3 phase conductors should all be black and the neutral is the bare. You can use the bare as the ground but you need to tape the ends on one of the blacks as white to identify it as the neutral. The #6 you have will be the grounding electrode(rod) conductor and goes from the panel in shop #2 to a ground rod outside shop #2, it does not go through the conduit between shops.


Edit: #2 Al is only good up to 90A as a subfeeder, so you are not to use a 100A breaker as the feeding breaker. Also the neutral in the subpanel is to be isolated, not bonded, to the panel/ground.
 

Last edited by pattenp; 02-01-19 at 07:50 AM.
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Old 02-01-19, 08:07 AM
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Yes, it is new service drop wire that the local utility uses here for residential drops.
Its is new off the spool, I usually use white shrink sleeve on ends and every few feet in between.

It is OK to use this type wires in a PVC conduit?

Yes going to use a 75amp main breaker in new panel for connection.
Nothing much over a light and one tool at a time that runs anyway just ran out of breaker space in 2 breaker panel.
OK, clear now on all the 5 wires, bare #6copper to my copper ground rod and not thru the conduit, and the other 4 thru the conduit back to panel #1, for 2 hots, & one neutral all insulated conductors, and the stranded bare aluminum to Ground in the #1 panel
 
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Old 02-01-19, 09:20 AM
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I see no issue putting it in conduit. The 1.25" conduit is the bare minimum for four #2's if a certain insulation is on them. The aerial cable may have a thicker insulation and require 1.5" conduit to meet fill requirements. Is there rating letters you can see stamped on the wire? Regardless, I recommend no smaller than 1.5" PVC conduit.
 
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Old 02-01-19, 09:32 AM
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I can buy 1.5" PVC I am pretty sure here, but will look at the wire more closely and advise if there is any writing on it
Thanks
 
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Old 02-01-19, 10:07 AM
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written on the conductors is
General Cable PowrServ (R) WP June 18 2018 3:08:34 #2 AWG AL XLPE 600V 90C
 
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Old 02-01-19, 11:20 AM
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If it is only a short distance as you previously wrote and the triplex you have was cheap given the triplex was never correct for your purpose I'd suggest just go with three #4 THWN and a green #8 copper instead.
 
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Old 02-01-19, 12:12 PM
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What brand panel do you have? 75A breaker is an odd egg.

Not seeing the insulation rating in the info you listed. XLPE is the material type of the insulation. I'm not sure if the wire insulation is fire resistant rated for inside installation.

Edit: The more I look for info on the wire you may have I'm not seeing that it should be used for where it may enter the structure. It's stated use is from the power pole to the service head.
 

Last edited by pattenp; 02-01-19 at 12:27 PM.
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Old 02-01-19, 12:53 PM
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Eaton is the brand, as I have a couple case lots if new BR type breakers. Not sure if I have a 75, but I may have? if not a 90?
Ray I not sure I follow your post, do you mean ,NOT to use the #2 Aluminum and buy some " three #4 THWN and a green #8 copper instead"? Ron
 
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Old 02-01-19, 02:01 PM
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Yes, what you have was never intended for what you are doing. #4 copper will be ok for a 75a breaker.
 
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Old 02-01-19, 03:10 PM
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Actually #4Cu is 85A and can be on a 90A breaker.
 
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Old 02-01-19, 09:57 PM
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This is a description of the wire, it is a tripex #2 AWG AL with insulation XLPE
this is the link to specs

https://html5.dcatalog.com/?docid=3b...535744&page=24

Would like to know if I can use it for burial between Main which is on outside wall to Sub that is on inside but only behind the Sheet tin of the outside wall.

mine is this one with 2 conductors and the bare ground, #2 gauge

https://html5.dcatalog.com/?docid=3b...535744&page=28
 
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Old 02-01-19, 10:44 PM
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Do you mean in conduit along with a fourth wire? I have to wonder how well the bare messenger intended for use in free air will hold up if buried.
 

Last edited by ray2047; 02-01-19 at 11:05 PM.
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Old 02-02-19, 07:50 AM
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The OH service drop cable you have is not to be used underground, even in conduit. All conductors need to be insulated with the proper insulation for below ground/wet location installations. The data sheet specifies what application the cable is to be used.

Edit: Being a service drop cable the bare conductor is designated as the neutral.
 
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Old 02-02-19, 08:15 AM
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And bare neutral isn't allowed in most cases past the service drop.
 
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Old 02-02-19, 08:17 AM
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Yes, ELMINATING the bare Ground being used underground in a conduit of correct size for burial , but by substituting the bare neutral , replacing it with another conductor to the package the same as the 2 hots ,only by marking it appropriately, making the bundle of 3 insulated conductors I neglected to state that below.

Other than the bare ground I see no differences in the cable as far as size, thickness number of wires or insulation all seems the same for overhead and Underground except for the bare ground wire which can be replaced. Insulation on both are XLPE and same thickness.
Does a bare copper ground have to be ran back to the main when it is used for a grounding rod both on the main and one at the sub?

I appreciate and heed your advise.
Ron
 
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Old 02-02-19, 08:25 AM
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The feeder needs the equipment ground going between panels. The electrode grounding conductor for the ground rods is for a totally different purpose, it's for lighting strikes, not for fault current clearing. The equipment ground is for fault current to insure the breakers trip on a fault. In separate structures with their own panels need separate grounding rods. You don't want a potential lighting strike out at the shop to travel back along the equipment ground to the main panel.
 

Last edited by pattenp; 02-02-19 at 11:09 AM.
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Old 02-02-19, 08:28 AM
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The feeder ground will need connect to the service panel as well as the conductor to the ground rod.

The subpanel sticky at the top of the forum can answer most of your questions.
 
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Old 02-02-19, 08:33 AM
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OK , understood, then I would have to run an insulated ground ( for underground use) thru the conduit of 3 insulated conductors also to connect both panels together even though the same bar on each panel will have its own ground rod also.

If I were to use the 90amp breaker in the sub, what gauge insulated ground wire between manels should be used?
 
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Old 02-02-19, 09:00 AM
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Thank you PCBoss, those are some great illustrations, I appreciate that, I copied and stored them for all my future reference. When you do not do this day in and day out you forget, and this is something that would get you into trouble if not just right.
 
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Old 02-02-19, 09:05 AM
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For 90A the equipment ground needs to be a #8 Cu or #6 Al

Remember any subpanels need to have the neutrals isolated from ground. Usually subpanels require the addition of a ground bar in the panel so only the neutrals are on the isolated bar.
 
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Old 02-02-19, 11:40 AM
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Remember any subpanels need to have the neutrals isolated from ground. Usually subpanels require the addition of a ground bar in the panel so only the neutrals are on the isolated bar.

Yes,, I keep extra bars as I have had to add them.
thank you
 
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