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100A meter panel w/ disconnect 320 feet to mobile home 100A panel w/disconnect

100A meter panel w/ disconnect 320 feet to mobile home 100A panel w/disconnect

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Old 06-11-14, 03:06 PM
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100A meter panel w/ disconnect 320 feet to mobile home 100A panel w/disconnect

I am in a very unpopulated rural area and am installing a feed from a pole with a meter and panel with a 100A service disconnect breaker to run about 320' to a newly placed mobile home with a panel that has a 100A main disconnect.

Both disconnect breakers are rated for CU/AL.

I believe I should run four conductors, probably using aluminum mobile home feeder cable such as supplied by Southwire.

I would use NOALOX or equivalent anti-oxidation grease at the termination points.

I plan to run the cable buried 20 inches underground in schedule 40 PVC electrical grade conduit to provide extra physical protection. I would use factory bent PVC risers at either end.

The neutral is bonded to ground at the meter panel. I would keep them separate at the mobile home (as they were previously wired) but would add one properly installed ground rod.

Southwire specifies their 2-2-4-6 AL-Mobile Home Feeder cable for 100A but I am quite certain I should use heavier wire for such a long run.

Could you advise me regarding the properly sized cable for this project, the proper size conduit for it, and anything else I should watch out for?

Finally - Home Depot may carry the cable in 500' rolls but it is pricey. Any tips on the least expensive way or place to purchase such a length?

Many thanks in advance. I have read through quite a number of related threads and appreciate all the help you all have been providing folks!
 
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Old 06-11-14, 03:52 PM
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Use 3/O aluminum conductors for this distance (700' round trip) to lose no more than 3% or 7.2 volts along the way.

Install two 8' ground rods at least 6' apart at the mobile home panel.

In a conduit you can run single conductors as opposed to multi-conductor cable which may make it easier to buy just how much you need. The wire must be wet environment rated such as THWN.
 
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Old 06-11-14, 06:09 PM
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Remember that voltage drop is dictated by load. If there is no load, there is no voltage drop.

Since we don't know what the expected load will be, I would assume somewhere around 60 amp load. (I base this on experience, nothing more). If you were to use this cable: Southwire 2-2-4-6 Aluminum MHF Wire (By-the-Foot)-30163099 at The Home Depot which HD sells by the foot, here are the results:

Voltage drop: 9.46
Voltage drop percentage: 3.94%
Voltage at the end: 230.54
 
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Old 06-11-14, 07:28 PM
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I plan to run the cable buried 20 inches underground in schedule 40 PVC electrical grade conduit to provide extra physical protection. I would use factory bent PVC risers at either end.
I see no good reason at all to run the feeder in conduit other than a conduit riser at the service pole and at the mobile home. If you aren't going to direct bury it, why spend the extra dollars on direct burial wire? If you just want to use a complete run of conduit, don't buy the mobile home feeder, but go to a supply house and buy what you need in aluminum Type XHHW.
 
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Old 06-11-14, 08:02 PM
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I missed the part where the OP wants to use conduit. 320' pull in PVC? that is going to be one heck of a pull! I suggest upping your conduit size by one and use steel 90's.

I would also just use direct burial MH feeder.
 
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Old 06-12-14, 07:47 AM
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320' pull in PVC? that is going to be one heck of a pull!
Yep, that's a difficult pull for a pro. The mobile home feeder also has a slight twist from the factory to keep the conductors together for direct burial installations which adds resistance and makes pulling in conduit twice as hard. I believe if I were going to try it I'd use conduit at least 2 sizes bigger than normal.
 
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Old 06-12-14, 12:41 PM
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You'll also need to add a disconnect, adjacent to and not attached to, the mobile home. It needs to be within sight and can't be more than 30' away.
 
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Old 07-14-14, 12:58 PM
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The feed installation is complete. The mobile home is being converted to a permanent home on a foundation thus the 4-wire feed was run from the 100 A 240 V breaker on the pole 310 feet to the 100 A breaker on the panel inside the home. It was buried 30" over most of the route.

I found a source of new twisted cable short ends on Amazon and bought a 350' roll of 2/0 2/0 2/0 1 twisted direct burial aluminum cable. However I wanted it to have further protection and put it in 2" PVC conduit with sweeps at each end. The #1 cable is used for ground. I am installing two 8' ground rods with proper clamps adjacent to the mobile home panel tied to the grounding strip. Neutral and ground are bonded only at the meter panel.

The 2/0 would not fit in the breakers at either end so I used CU-AL approved split bolts and #1 copper pigtails to tie into the breakers. Antioxidant on all aluminum connections. The split bolts are wrapped with multiple layers of 3M rubber electrical tape.

Thank you to all who submitted comments on this installation.
 
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Old 07-14-14, 02:36 PM
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Sounds good. Thanks for letting us know how it was finished.
 
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