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View Full Version : What size wire do I need to run to get a 100amps. 225ft. using direct burial wire?


GarryOne
Jun 3, 2010, 10:42 AM
What size wire do I need to run to get a 100amps. 225ft. using direct burial wire coming from a 200amp. Service? Any info. Would be appreciated.

Regards,

Garry

stanfortyman
Jun 3, 2010, 05:32 PM
What do you mean "get 100 amps"?

Is the load actually 100A?
Or is this for a 100A sub-feed?

GarryOne
Jun 3, 2010, 08:57 PM
When I say, get a 100amps, I mean get a 100amps. as close as I can to it, on a 100A sub-feed, I guess. I'm going to get a 200A service to my house from the electric co. & plan on taking a 100 of those amps. Down to the shop, which is about 225' away from the house. I would like to be able to run a welder (225A), & a 110 freezer & a couple of lights at the same time. Now I've heard you can even run aluminum for direct buriel cable. I was told that I could use #1 Ought aluminum buried in 1 1/2" foam core 3 conductor wire, as my house does not have 4 conductor wire, it was wired in 1961. I don't live in a city, so there is no code except what the electric co. might require. However I do won't to be safe. Do you think the above would be safe? If not, what would be the safest, cheapest way to go? Any info. Would be appreciated.

Regards,

Garry

stanfortyman
Jun 4, 2010, 05:04 AM
When I say, get a 100amps, I mean get a 100amps., as close as I can to it, on a 100A sub-feed, I guess. Like I implied, a 100A sub-feed is quite different than a constant 100A load. Your explanation cleared that up.


I'm going to get a 200A service to my house from the electric co. & plan on taking a 100 of those amps. Down to the shop, which is about 225' away from the house. I would like to be able to run a welder (225A), & a 110 freezer & a couple of lights at the same time.
A 100A sub-feed should be fine for that. The welder will draw maybe 50-60A max (@ 240v), but for only very short periods.


Now I've heard you can even run aluminum for direct buriel cable. I was told that I could use #1 Ought aluminum buried in 1 1/2" foam core 3 conductor wire, as my house does not have 4 conductor wire, it was wired in 1961.
Yes, you can go with direct burial, but for that distance I suggest conduit. Actually I pretty much always suggest conduit.
I have no idea what "foam core" cable you are describing. That is nothing I have ever heard of. What you describe sounds more like high-voltage primary cable.
The fact that your house has only 3-wire makes absolutely no difference. You MUST use a "4-wire" feeder to the shop. The feeder originates in the main service panel and that is where the connections are made. If you need this explained further let us know.


If I were to build this job I would use 3- 1/0AL for the feeders conductors with 1- #2AL for the equipment ground.

You also need at least one grounding electrode at the shop. Do not confuse this grounding electrode with the equipment ground run with the feeders. They are two very different things.

GarryOne
Jun 4, 2010, 08:47 AM
Ok, thanks very much. I was told plumbers use that foam core & its like conduit.

Regards,

Garry

stanfortyman
Jun 4, 2010, 01:00 PM
Plumbers do a lot of weird things.

If it's not electrical conduit don't use it.