Another electrical? Check my figures

moresmoke

Well-known Member
Location
E ND
I want to get my generator set up correctly this summer. The transfer switch is on the pole 175 feet from where the generator lives. 50A 4 wire plug on the generator. I want to connect transfer switch to a box on the wall next to the generator. Will run rubber cord between generator and wall.

My figuring says I need #2 wire. It looks like 2-2-2-4 SE is the most economical choice. Did I get this right?
 
Another thought...

Is there any way to run underground in PVC conduit?

Reason is, you are installing this as emergency back up. Running overhead, your overhead wiring will be subject to the same hazards that may have knocked the power out, ice build up, falling trees, lightening, etc.

If you do go underground, it will need to be copper, not aluminum.
 
It will be underground. No conduit, but that is normal here, no rocks to be found. Already have the rubber cord from a previous installation.
 
2-2-2-4 URD aluminum is probably the most cost-efficient for direct burial I just bought some last week for direct burial of a service to a barn. $1.25 per foot at Home Depot. $1.75 at my local electrical-supply place. No conduit required except where it enters and exits the ground (according to code in MI). I do not know of any SE or SER rated for burial. URD is what you want if putting it in the ground.
 
Dumb question:
What is the expected life of buried electrical cables? When our local RES buries a power line they expected it to be reliable for at least 15 years and would need to be replaced at about 20 years. Do buried yard cables last about the same?
 

Cab Tire, SOW etc is not for burial or use in a conduit.
Direct burial cable sounds like a food idea however it's not if, it's when it will short out.
PVC conduit is cheap and simple to install then pull in any sort of U type cable .
Grounding at the generator requires caution to avoid running neutral current through the ground system. The gen set defiantly requires grounding.
 
Rubber cord won't hold up direct burial.

It will decompose very quickly exposed to sun, moisture and rodents.

Even run in conduit it will eventually get water in it, rot it away.
 
ss55, not a dumb question!

A lot depends on the conditions, depth of installation, proper installation, protection from the elements, rodents, exposure to traffic, they are all allergic to lawn mowers! LOL

Personally I don't like direct burial cable, but again a lot depends on conditions. It might last 5 years, might go 50, who knows...

I favor PVC conduit, installed by code requirements as per depth, traffic protection, and ground penetration/termination. Then run the proper size stranded wire, THHN or THWN insulation, should last indefinitely as long as it doesn't get physically damaged. The big advantage is the wire can be pulled and replaced without having to dig the ditch again!
 
My place in northern Michigan has an underground service that was installed in 1974. It is URD aluminum with no conduit. When I bought the place on foreclosure, I found a low voltage problem on one line. Ended up someone had run a post-hole digger right through the URD cable at one time and then just twisted it together and wrapped with duct tape. NOT a great underground repair. Other then that damaged spot that I fixed with an underground splice kit-the cable looks and works fine. #2 aluminum and 43 years old. I have installed new URD in many places and never had a call-back unless it was damaged by someone digging.
 
I had a problem once with wires in a conduit underground, the conduit got water in it and when it froze it stretched the
wires until it broke one. Anyone else ever have this happen? Since then I have used direct burial with no problems.
 
Russ mn, having worked at local REC for 32 years, found several cases like that where water in conduit froze and separated the USE. We now direct bury it all, and works good until it gets disturbed.
 

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