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Using 2-2-4 + extra wire as I can't find 2-2-2-4 aluminum feeder

Using 2-2-4 + extra wire as I can't find 2-2-2-4 aluminum feeder

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  #1  
Old 12-01-14, 03:17 PM
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Using 2-2-4 + extra wire as I can't find 2-2-2-4 aluminum feeder

Hi all

I need 2-2-2-4 MHF to run from a 90A breaker in my main panel to a 100A subpanel 60ft away.

The only store that carries 2-2-2-4 is 2.5 hours away, which is less than ideal considering money spent on gas. Can I use 2-2-4 and run an extra wire with it?

If so, can someone explain to me which cables are the #2 and which are #4? I thought that in 2-2-2-4 the #4 was ground, but in the 2-2-4 I see on sale it's ungrounded, which means the #4 is the neutral.

If that's the case, will I just have to run a third #2 wire and colour code them to make clear that the neutral is being run as ground, and the extra #2 is the neutral?

I'm direct burying it and running it in the house, in conduit, too. The MHF here is 'triple rated' (USE, RHH, RHW-2 I think) so it's all good.

Thanks
 
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  #2  
Old 12-01-14, 04:42 PM
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I'm direct burying it and running it in the house, in conduit, too.
That's confusing.

How are you going to use direct burial mobile home wiring and run another wire with it ?
 
  #3  
Old 12-01-14, 05:25 PM
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Unless dual rated the URD cannot be run in the house.
 
  #4  
Old 12-01-14, 06:55 PM
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The only store that carries 2-2-2-4 is 2.5 hours away
Do you have a supply house near you, they can probably special order the mobile home feeder and have it in a few days. One other option I see is from a big box store, just buy the length you need for the ground in Type USE. I think this would work. Order it online from Home Depot and have it shipped to your closest store to avoid freight charges. Throw it in the ditch with the URD you can get locally just for the ground. All you really need is a #6 aluminum though so maybe you can look around and find it.

Southwire 1 Stranded Aluminum USE Wire (By-the-Foot)-27283190 at The Home Depot

Here is some #6 USE

https://www.platt.com/platt-electric...spx?zpid=69647

I still think your local supply house is the best source.
 
  #5  
Old 12-02-14, 06:38 AM
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Luckily a friend of mine is driving up around the area where I can get the 2-2-2-4, so they're going to stop by and pick it up for me.

But to the points raised already - For some reason, despite living in Tennessee which has a lot of mobile homes, the 2-2-2-4 feeder seems to be incredibly uncommon. I'm not too familiar with code, but I do know that around here they seem to enforce only the 2008 NEC, and perhaps that still allows triplex hence the scarcity of suppliers stocking the quadruplex.

I'm still confused by the whole #2/#4 issue though, could anyone clear it up for me?

In 2-2-2-4 I assume the 4 gauge wire is the ground, but 2-2-4 doesn't run ground so what's the #4 wire there? Do they intend it to be used as neutral? If so, why is neutral #2 in one and #4 in the other?

Then a follow-up, seeing as mobile home feeder is all jacketed, dual/triple rated etc etc, does that mean there's literally no difference between the wires except for the gauge/colour coding? What I mean by that is, are all wires insulated, including ground? So, if the 2-2-4 is live live neutral, and 2-2-2-4 is live live neutral ground (in that order), I could if I wanted to run a 4th wire with it (of appropriate ratings/jacket) and pick and choose which wires I use for what?
 
  #6  
Old 12-02-14, 08:02 AM
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In 2-2-2-4 I assume the 4 gauge wire is the ground, but 2-2-4 doesn't run ground so what's the #4 wire there?
The #4 is a reduced neutral. I prefer using a full sized neutral.

around here they seem to enforce only the 2008 NEC,
The 2008 NEC requires a 4-wire feed to a 120/240 volt single phase subpanel.

seeing as mobile home feeder is all jacketed, dual/triple rated etc etc, does that mean there's literally no difference between the wires except for the gauge/colour coding?
Mobile home feeder is not jacketed, are you sure you understand exactly what it is? What you describe as jacketed sounds like it might be SER cable which CANNOT BE USED UNDERGROUND.

This is 100 amp mobile home feeder with a reduced neutral.

http://www.homedepot.com/p/Southwire...3001/202316213

This is SER cable.

http://www.wireandcabletogo.com/2-3-...FepAMgod2mIACQ
 
  #7  
Old 12-02-14, 08:21 AM
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I'm still confused by the whole #2/#4 issue though, could anyone clear it up for me?
In most residential settings, the code allows the neutral to be a size smaller than the hots on the assumption of a certain amount of load diversity in the home. In the case of 2-2-4 cable, the #2s are the hots and the #4 is a shared neutral+ground. In a 2-2-2-4 cable, two of the #2s are hots, one of the #2s will have a white strip or dash on it and that is the neutral, and the #4 is the dedicated ground.

It is becoming less common to use a reduced neutral these days unless you have done a specific load calculation to prove it's safe to do so.
 
  #8  
Old 12-02-14, 08:53 AM
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Mobile home feeder is not jacketed, are you sure you understand exactly what it is? What you describe as jacketed sounds like it might be SER cable which CANNOT BE USED UNDERGROUND.

Read more: http://www.doityourself.com/forum/el...#ixzz3Kl68LFI7
My incorrect use of terminology is creating confusion.. By jacketed I was trying to say insulated/suitable for direct bury.

This is what I'm planning on using, with manufacturer specs found here.

RHH, RHW-2, USE-2 triple rated. Suitable for direct bury, and can go inside the crawlspace up to the panel in conduit, right?
 
  #9  
Old 12-02-14, 01:35 PM
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As long as the cable has the RHW-2 mark in addition to the USE-2 mark, you can run it indoors in a fully assembled conduit system. Plain USE or URD cannot go indoors even in conduit. The one you linked looks good, just make sure the cable they have in the store has both ratings marked on the conductors.
 
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