question about minimum hole/bushing size into both main panel and sub panel boxes

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joerm64

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Does anyone have a link or know off hand what would be the minimum hole (with bushing) size required when feeding 4- 2/0 aluminum XLPE RWH USE-2 wires into the main panel box and also the sub pane box in the detached garage?
I'm going to use 2-1/2" schedule 40 PVC in the trench and come out of the ground via 2-1/2" PVC schedule 80 sweeps and LB's into the outside wall but where the wires enter the buildings (as I understand it) because of the 4 wires being RWH USE-2 XLPE they don't need conduit protection indoors? If this is true, it's going to look like a bundle of 4 seperate wires... should I zip tie them together every so often until they reach the panel? I'd like to reduce the size of the hole I have to knock out of the side of the main panel box to feed the wires as it's already fairly crowded inside the box and 2-1/2" seems excessive. Also if I may ask, if I use 2-1/2" pvc through the wall (from the LB to the inside wall) should I use a bushing flush with the surface of the inside wall? Does the empty space inside the conduit where it enters the building need to be filled with some sort of fire resistant insulating material? What would be best way to run the 4 wires where the spill out of the inside wall and on to their lugs inside the panel box?
 
joerm64 said:
...where the wires enter the buildings (as I understand it) because of the 4 wires being RWH USE-2 XLPE they don't need conduit protection indoors? ...
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Incorrect.

Type USE is not permitted for interior wiring.

And unless the each RHW conductors is listed/labeled as single conductor cable, it cannot be run exposed.

See the first Applications bullet point in this product spec' sheet: http://www.southwire.com/ProductCatalog/XTEInterfaceServlet?contentKey=prodcatsheetOEM7
 
You should call an electrician because what you are describing is a code violation.
 
Smart $ said:
Incorrect.

Type USE is not permitted for interior wiring.

And unless the each RHW conductors is listed/labeled as single conductor cable, it cannot be run exposed.

See the first Applications bullet point in this product spec' sheet: http://www.southwire.com/ProductCatalog/XTEInterfaceServlet?contentKey=prodcatsheetOEM7
Click to expand...


Thanks Smart,
I'll be sure to go ahead and run it through conduit from start to finish into the boxes.. which we're only talking about another 3' max on each end. Any thoughts on what the minimum hole/bushing size for this size wire into the main and sub panel? While the wire will be rated for 100 amps (and will connect to a 100 amp sub panel) I thought I'd connect them to an 80 amp circuit breaker in the main panel... thus over protecting the circuit?
 
joerm64 said:
btw the wire is labeled "2/0 alum 1/C XLP USE-2-8000AL" Does the "1/C" indicate it is single conductor?
It's on 2 600' reels.
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If what you just mentioned is all that is marked on the conductor - it is USE cable only and is not rated for indoor usage. It needs to also have additional rating such as RHW or RHH to be a conductor type rated to enter a building.

1/c is seldom seen but must be a single conductor and not a multiplex conductor assembly.
XLP - means cross linked polyethylene
USE - means it is type "underground service entrance cable"
-2 likely means it can be used as 90 deg C insulation
8000 is the aluminum alloy designation
 
kwired said:
If what you just mentioned is all that is marked on the conductor - it is USE cable only and is not rated for indoor usage. It needs to also have additional rating such as RHW or RHH to be a conductor type rated to enter a building.

1/c is seldom seen but must be a single conductor and not a multiplex conductor assembly.
XLP - means cross linked polyethylene
USE - means it is type "underground service entrance cable"
-2 likely means it can be used as 90 deg C insulation
8000 is the aluminum alloy designation
Click to expand...

While I haven't opened the shrink wrapped reels and inspected the wire sheathing, I did specifically ask for 2/0 alum conductor that could both be directly buried and enter a building too. When I google the item #/description from the delivery invoice the top search link is Priority cable and wire type:

Aluminum RHH/RHW-2/USE-2 600v 90c XLPE insulation.

Am I confusing "rated to enter a building" with thinking it can enter a building without conduit? Easy enough for me to enclose the 4- 2/0 wires in conduit inside the building in both buildings if so.

I'm wondering how much I can reduce the 2-1/2" conduit to something smaller where I must punch a hole in the side of the panel box.. the smaller the better I'm thinking? (while being NEC compliant)
 
joerm64 said:
While I haven't opened the shrink wrapped reels and inspected the wire sheathing, I did specifically ask for 2/0 alum conductor that could both be directly buried and enter a building too. When I google the item #/description from the delivery invoice the top search link is Priority cable and wire type:

Aluminum RHH/RHW-2/USE-2 600v 90c XLPE insulation.
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I and the inspector will probably question whether the product description takes the place of proper UL marking on the wire/cable itself.


Sent from my XT1585 using Tapatalk
 
GoldDigger said:
I and the inspector will probably question whether the product description takes the place of proper UL marking on the wire/cable itself.


Sent from my XT1585 using Tapatalk
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Assuming for a minute that it is properly UL marked does NEC describe limitations/restrictions on hole size (and matching bushing) punched into the metal side of the panel box?
 
Welcome to the forum!

Before we get into bushing size, lets back up a minute: why are you running 2/0 AL to a 100A subpanel, especially when you are going to protect it with an 80A breaker in the main panel? #4 CU or #3 Al are good for 85 and 90A respectively, and your neutral and ground do not need to be the same size as the ungrounded conductors.

2/0 Al is rated 135A @ 75*C; unless you have a hideously long run (500+'), high ambient temps (north of 120*F) and a sustained high amperage (50+A) draw expected in your subpanel, you will not need to upsize your wire that much. While you may be able to get 125/150A breakers for your panel, if your main is a 200A, you may not be able to add an 80A+ load to it.

Second, what load(s) do you plan running from this subpanel? How did you determine 80-135A (an odd range for sure based on your proposed OCPD and wire) size would be needed in the subpanel? Have you done a load calculation on your main panel?

Anyway, to answer your questions, here is an ampacity chart:

http://www.cerrowire.com/ampacity-charts

and a conduit fill chart as single conductors will require a raceway:

http://sparkyjohn.com/pipefill/pipefill.pdf

if you use different size conductors, you will need to calculate their areas, add together, and use a conduit size that is appropriate for them. 2/0 across the board as you propose would need a 2" conduit. 4 #4 conductors (or smaller for neutral and ground) can go in a 1" conduit.
 
JFletcher said:
Welcome to the forum!

Before we get into bushing size, lets back up a minute: why are you running 2/0 AL to a 100A subpanel, especially when you are going to protect it with an 80A breaker in the main panel? #4 CU or #3 Al are good for 85 and 90A respectively, and your neutral and ground do not need to be the same size as the ungrounded conductors.

2/0 Al is rated 135A @ 75*C; unless you have a hideously long run (500+'), high ambient temps (north of 120*F) and a sustained high amperage (50+A) draw expected in your subpanel, you will not need to upsize your wire that much. While you may be able to get 125/150A breakers for your panel, if your main is a 200A, you may not be able to add an 80A+ load to it.

Second, what load(s) do you plan running from this subpanel? How did you determine 80-135A (an odd range for sure based on your proposed OCPD and wire) size would be needed in the subpanel? Have you done a load calculation on your main panel?

Anyway, to answer your questions, here is an ampacity chart:

http://www.cerrowire.com/ampacity-charts

and a conduit fill chart as single conductors will require a raceway:

http://sparkyjohn.com/pipefill/pipefill.pdf

if you use different size conductors, you will need to calculate their areas, add together, and use a conduit size that is appropriate for them. 2/0 across the board as you propose would need a 2" conduit. 4 #4 conductors (or smaller for neutral and ground) can go in a 1" conduit.
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From the transformer on the pole in my front yard to the 200 amp main is 70' from there out to the detached garage is 270' for a total run of 340'. At the main I read about 240v. My plan is to over size because I will be running a large transformer based tig welder who's operating instructions suggests a 100amp circuit. I doubt the welder will ever be pushed to that extreme but should it approach an amp draw anywhere near that I'd like the 80 amp breaker to call time out well before hand. Doing a total load calculation on the 200 amp main suggests adding the 80 amp breaker should be ok. I'll be running 4 2/0 alum RHH RWH USE-2 XLPE single conductors because that is what I have available for this purpose. The conduit sizing chart indicates the most I could reduce the conduit down to is 2" so I guess I'll be punching a 2" hole in the side of my panels. I just wasn't sure if NEC allows at certain choke points along the wire run ie. Where it enters metal junction/main/sub-panels etc that larger reductions are allowed?
Thanks for your help and the links to the charts
 
Smart $ said:
Type USE is not permitted for interior wiring.
Click to expand...


joerm64 said:
Thanks Smart,
I'll be sure to go ahead and run it through conduit from start to finish into the boxes.
Click to expand...

You seem to be missing smarts point, USE cannot be used inside, not for 10' not for just 3' even if in pipe.

338.12 Uses Not Permitted.(B) Underground Service-Entrance Cable.

Underground service-entrance cable (USE) shall not be used under the following conditions or in the following locations:

(1) For interior wiring

(2) For aboveground installations except where USE cable
emerges from the ground and is terminated in an enclosure
at an outdoor location and the cable is protected in
accordance with 300.5(D)
Click to expand...

Based on your posts in this thread in my opinion your best bet is to hire an electrician familiar with residential work.

You will get a better and code compliant job the first time.
 
iwire said:
You seem to be missing smarts point, USE cannot be used inside, not for 10' not for just 3' even if in pipe.



Based on your posts in this thread in my opinion your best bet is to hire an electrician familiar with residential work.

You will get a better and code compliant job the first time.
Click to expand...

Not even 2/0 alum RHH RWH USE-2 XLPE single conductors indoors? I'll have to call the wire sale's agent Monday morning.
 
joerm64 said:
From the transformer on the pole in my front yard to the 200 amp main is 70' from there out to the detached garage is 270' for a total run of 340'. At the main I read about 240v. My plan is to over size because I will be running a large transformer based tig welder who's operating instructions suggests a 100amp circuit. I doubt the welder will ever be pushed to that extreme but should it approach an amp draw anywhere near that I'd like the 80 amp breaker to call time out well before hand. Doing a total load calculation on the 200 amp main suggests adding the 80 amp breaker should be ok. I'll be running 4 2/0 alum RHH RWH USE-2 XLPE single conductors because that is what I have available for this purpose. The conduit sizing chart indicates the most I could reduce the conduit down to is 2" so I guess I'll be punching a 2" hole in the side of my panels. I just wasn't sure if NEC allows at certain choke points along the wire run ie. Where it enters metal junction/main/sub-panels etc that larger reductions are allowed?
Thanks for your help and the links to the charts
Click to expand...

You're welcome. Sizing for welders is HIGHLY variable, they even make 6-50 to 6-15 adapter cords to run large 50A cord and plug welders on 15A circuits. Since this is your main draw/load, I would double check the instructions, even make a temporary connection in your main panel to see what kind of load you'll actually be using. What is the exact make/model of the welder?

To the main panel, the 2.5" conduit can be run to a large (12" x 12", tho dont quote me on that) j-box and the 2/0 connected to #4 CU/#3AL (on an 80A breaker) via Polaris or other suitable connectors, then run thru a 1" conduit to your main panel. If it is already kinda full, working with #4 CU will be much easier than 2/0. The 2/0 can go right thru to the subpanel lugs, but like iwire mentioned, that cable cannot be run indoors except to service or metering equipment. eta: you can use the cable you have if there are exterior mounted j-boxes on both ends. Might as well transition there to a smaller, indoor rated cable

270' is a decent distance, but barring other major loads, 2/0 is serious overkill as is 2.5" conduit. You already have the wire (tho it may be going back), if you already have the conduit, I'd send that back as well. 1.25" would be plenty for #4CU/#3AL.
 
JFletcher said:
You're welcome. Sizing for welders is HIGHLY variable, they even make 6-50 to 6-15 adapter cords to run large 50A cord and plug welders on 15A circuits. Since this is your main draw/load, I would double check the instructions, even make a temporary connection in your main panel to see what kind of load you'll actually be using. What is the exact make/model of the welder?

To the main panel, the 2.5" conduit can be run to a large (12" x 12", tho dont quote me on that) j-box and the 2/0 connected to #4 CU/#3AL (on an 80A breaker) via Polaris or other suitable connectors, then run thru a 1" conduit to your main panel. If it is already kinda full, working with #4 CU will be much easier than 2/0. The 2/0 can go right thru to the subpanel lugs, but like iwire mentioned, that cable cannot be run indoors except to service or metering equipment. eta: you can use the cable you have if there are exterior mounted j-boxes on both ends. Might as well transition there to a smaller, indoor rated cable

270' is a decent distance, but barring other major loads, 2/0 is serious overkill as is 2.5" conduit. You already have the wire (tho it may be going back), if you already have the conduit, I'd send that back as well. 1.25" would be plenty for #4CU/#3AL.
Click to expand...

Thanks, It's a Miller DialArc HF with PFC Tig welder I rescued it from a trip to the scrap yard along with a foot control pedal and water cooler for $100. Turns out in only needed a large contacter replaced :O)

The operator's manual has a graphic chart that showing the recommended fuse size for this welder.

dialarc hf.jpg
 
joerm64 said:
Not even 2/0 alum RHH RWH USE-2 XLPE single conductors indoors? I'll have to call the wire sale's agent Monday morning.
Click to expand...
What you have is insulated conductors that must be installed in a wireway, raceway, or within other acceptable enclosures.

USE is rated for direct burial. It does not have flame and smoke properties that are required for insulated conductors used inside of a building.

If the conductor has multiple ratings on it like USE/RHW/RHH, then it has properties of all three of those markings, RHW and RHH conductors can be used indoors, but the USE property still allows it to be direct buried. If you have RHW only marking it can be used both indoors and outdoors but it can not be direct buried, it can be in a buried raceway though.
 
iwire said:
Based on your posts in this thread in my opinion your best bet is to hire an electrician familiar with residential work.

You will get a better and code compliant job the first time.
Click to expand...

I agree with Bob and therefor I am closing the thread based on the forum rules.

This site is designed for:


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* This NEC� Forum is for those in the electrical and related industries. Questions of a "How-To" nature by persons not involved in the electrical industry will be removed without notice.

Knowledge and the practical application of the National Electrical Code is an essential part of all electrical installations. If it's important for you to understand the National Electrical Code, then look no further.
Click to expand...


Roger
 
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