Overhead Detached Garage feed

[serviceguy]

Hi All,

while I am aware that the best way to do this would be using a buried conduit, money and time do not allow for that at this time.

I want to feed a subpanel in my detached garage using overhead quadplex wire rated for 100A (2-2-2-2) @ 240V 1 phase and I believe that would be to code (span is about 50' more or less), just having a hard time finding a 4 conductor (3 insulated + 1 bare ACSR I believe would do) that has one of the insulated wire of a different color or that is striped (for the neutral).

Any suggestion? Can you point me in the right direction? Am I correct in my selection for the application?

I would much appreciate any input.

Thanks!

 

[pattenp]

#2 Al is 90A when used as a branch feeder.

 

[bigb56]

The few times we have done this we bought triplex and wrapped an additional sunlight resistant conductor around it. Quadplex is not easy to get in small amounts.

 

[nadogail]

Try several electrical supply houses in your nearest large city.

Look for one who supports small contractors and DIYers.

 

[wyliesdiesels]

Hi All,

while I am aware that the best way to do this would be using a buried conduit, money and time do not allow for that at this time.

I want to feed a subpanel in my detached garage using overhead quadplex wire rated for 100A (2-2-2-2) @ 240V 1 phase and I believe that would be to code (span is about 50' more or less), just having a hard time finding a 4 conductor (3 insulated + 1 bare ACSR I believe would do) that has one of the insulated wire of a different color or that is striped (for the neutral).

Any suggestion? Can you point me in the right direction? Am I correct in my selection for the application?

I would much appreciate any input.

Thanks!

Here ya go. However, #2 al has 90a ampacity.

Min qty is 100'. Maybe sell the remainder?

The lugs in the panel are not rated for ACSR, so you would either need to transition on each side, at a weatherhead, to copper or aluminum building wire. Or order the optional messenger cable made of AAC or 6201 aluminum alloy.

https://www.wireandcableyourway.com...druplex-acsr-overhead-service-drop-cable.html

If you really need 100a, you will need to upsize to 1/0 unless you can find some #1 al quadplex...

EDIT: i comment about building wire ampacity so much that i forgot this was for free air use which has higher ampacity...

The few times we have done this we bought triplex and wrapped an additional sunlight resistant conductor around it. Quadplex is not easy to get in small amounts.

yup even WaCYW has 100' min...

 

[Bert_]

#2 AL is more than enough for 100a, the ampacity is higher in free air. I'd usually use a #4 overhead wire for 100 amps, but that is with crimp connectors that are rated 90*C. I'm guessing you will be using split bolts or something rated 75*C

As stated quad is harder to find. For only fifty feet I'd be tempted to just wrap another xhhw on. You will not find quad with a white wire since it is usually intended for 3 phase.

 

[wyliesdiesels]

#2 AL is more than enough for 100a, the ampacity is higher in free air. I'd usually use a #4 overhead wire for 100 amps, but that is with crimp connectors that are rated 90*C. I'm guessing you will be using split bolts or something rated 75*C

As stated quad is harder to find. For only fifty feet I'd be tempted to just wrap another xhhw on. You will not find quad with a white wire since it is usually intended for 3 phase.

yeah, free air, whoops.

 

[Norcal]

Quadplex, Triplex, are not recognized wiring methods by the NEC. That being said, I would be extra conservative when using it since it's not a single conductor in free air.

 

[pattenp]

yeah, free air, whoops.

I didn't think about being free air when I said 90A for #2Al. Stuck in the same train of thought.

 

[pattenp]

Quadplex, Triplex, are not recognized wiring methods by the NEC. That being said, I would be extra conservative when using it since it's not a single conductor in free air.

I'm not following you on this. How does the marketed name of a wire assembly constitute a wiring method? It's not a listed cable in the NEC because it's not a sheathed cable. It's an assembly of single conductors of type USE or RHW or such, which are listed.

 

[Bob P1]

Well, I get the time & money part, every project has its price. Would you really want to do this job twice? I'd get live with what you got now, even if it was just an extension cord. Not sure how far you have to go with the trench, but you only have to do it once!

 

[Norcal]

I'm not following you on this. How does the marketed name of a wire assembly constitute a wiring method? It's not a listed cable in the NEC because it's not a sheathed cable. It's an assembly of single conductors of type USE or RHW or such, which are listed.

There are no markings on the individual conductors.

 

[pattenp]

There are no markings on the individual conductors.

I thought they had the wire type surface printed on the conductors. Is it just the aerial that doesn't have markings?

 

[alfredeneuman]

yeah, free air, whoops.

Table 310.15(B)(17) (formerly Table 310.17) Allowable Ampacities of Single-Insulated Conductors Rated Up to and Including 2000 Volts in Free Air,

Triplex and quad aren't single conductors

 

[pattenp]

I think you need to use table 310.15(b)(20).

 

[Norcal]

I think you need to use table 310.15(b)(20).

The conductors listed in that table are what I would call special purpose conductors, not going to be found in big box stores or the average supply house.

 

[grounded-b]

All Triplex/Quadplex has "identified" conductors -look for the raised ribs on the insulation, just like lamp cord. Pick one and tape it white on both ends for your neutral

 

[serviceguy]

It would have to run about 50', the only fitting one I've found so far is a Quadplex 2-2-2-2 for 3 phase drops that would cost $80 as quoted by the supplier. All conductors (minus the ground) are black, I guess I could mark the neutral with tape as mentioned by grounded-b. It's a question for the building inspector at this point.

The issue with burying the conductor is that my property is extremely rocky an one big oak is also in the way of shortest route to the garage (unless I cut through the tarmac driveway which I'd rather avoid doing).

Overhead is not ideal in any possible way, and the aforementioned oak has already pushed the current sub-par, sub-code but pre-existing 120V line to the ground during the recent snow storm with 'only' 3' of snow, but the cost seems marginal and the time involved would not be much either, which would allow me to procrastinate the real deal job to whenever...

 

[alfredeneuman]

All Triplex/Quadplex has "identified" conductors -look for the raised ribs on the insulation, just like lamp cord. Pick one and tape it white on both ends for your neutral

They're not identified as to type (THWN, XXHW, etc ), unless the identification is somewhere other than cable itself (although it's supposed be on the cable)
In order to use Table 310.15(B)(20), they must be labeled as such


The same is true with NM cable. it's apparent that the conductors are THHN, but they can't used individually because they're not marked.

 

[Bert_]

I don't want to say that we should ignore any part of the code but the conductor marking, or lack of, is nit picking. It is XHHW or more likely XLPE, rated 90*C. I would use table 310.15(B)(20) and not worry about it. #2 aluminum overhead is more than enough for 100a, I would use #2 for up to 150A.

No wonder the code book keeps getting thicker every year...

 

[Norcal]

I don't want to say that we should ignore any part of the code but the conductor marking, or lack of, is nit picking. It is XHHW or more likely XLPE, rated 90*C. I would use table 310.15(B)(20) and not worry about it. #2 aluminum overhead is more than enough for 100a.

No wonder the code book keeps getting thicker every year...

As I wrote in a earlier post, triplex, & quadplex are not recognized by the NEC as a wiring method, since it's use is intended by PoCo's & they are not under the NEC, that being said I would use it as there is no better way for a overhead drop, but only with conservative ampacities and that would be 90A for #2 AL since there no markings.

 

[alfredeneuman]

It is XHHW or more likely XLPE, rated 90*C.

XHHW insulation = XLPE

http://www.southwire.com/products/XHHWOEM.htm

 

[expedient electric]

5 years later but I use quadplex which is type (USE) with a steel reinforced bare wire for support. I bought 35ft today at an electrical supplier. As far as the buildings I connect to a 4-wire SER going from the main panel up the outside of the house, then to the quadplex overhead then back to SER to the sub panel on the garage. SER can run inside or outside without conduit above ground. Wedge connectors and glass insulators to secure the overhead to the structures. As high as possible at least 12ft. Even higher above water or driveways depending. There's a plethora of connectors you can use, I typically hit linemen up for free ones. Those alum splicer/reducers with the Allen bolts work good, fill them with noalox anti oxidant grease. I'm going to reconfirm my strategy with the inspector tomorrow but it'll probably work swell. I also use plastic splice covers from the power company that snap over my connections.