wiring size?

[doug webb]

Got to run underground in conduit for 75 feet between panel boxes for shop....15 amps twice........lights, fans and refrigerator....2 5000 btu a/c's .........wire size? thanks

[Dennis Peacock]

Copper #6 SEC (Sevice Entrance Cable). This will carry you up to 70 Amps safely as well as provide you 220V power to the shop.

[doug webb]

Many thanks Dennis......I be a dumb ol plumber but I know when to ask questions........Thanks again......doug

[Jerry Olexa]

Go w dennis's advice but always IMHO go a little MORE than you need. You don't want to have to re dig that trench. I learned at my cabin where I had to go underground about 250 ft. I added phone wire in the trench to keep that service underground too and probably overwired. Be sure to have capacity for a 240V lines for tools u may add later. My 2 cents...G Luck

[Rob Russell]

First, SE cable is specifically prohibited for underground installations per NEC article 338.12(A). You could use USE, which is Service Entrance Cable for Underground use.

Whichever cable you're talking about, there is NO WAY I'd want to pull SE or USE cable through conduit - that would be a major pain to pull. I'd run individual conductors - THWN. #6 THWN is rated for 65 amps, per table 310.16.

Dennis - where did you get 70 amps worth of ampacity for #6 SEC?

Rob

[Dennis Peacock]

Dennis - where did you get 70 amps worth of ampacity for #6 SEC?

Rob

Good Morning Rob....it's a type-o.....I meant to type 60 (sixty).
Besides that? I didn't know it wasn't cool to pull SEC in conduit. We used to do it all the time when I worked as an electrician, even up through 1/0 SEC.

Ok Doug....pull three strands of #6 copper inside your conduit. Just don't do like I guy I know and pull a #12 to his shop and burned it down. He was told to NOT run that 12 wire, but to run a #8....some folks just don't listen.

[Rob Russell]

Good Morning Rob....it's a type-o.....I meant to type 60 (sixty).
Besides that? I didn't know it wasn't cool to pull SEC in conduit. We used to do it all the time when I worked as an electrician, even up through 1/0 SEC.

Ok Doug....pull three strands of #6 copper inside your conduit. Just don't do like I guy I know and pull a #12 to his shop and burned it down. He was told to NOT run that 12 wire, but to run a #8....some folks just don't listen.

Dennis,

I'm not saying you can't pull SE in conduit - I just wouldn't want to do it. The #2 SER I've run is enough fun to work with in the basement, let alone the thicker USE through conduit.

If Doug is installing a 240v subpanel, he needs 4 conductors - not 3. If he uses a 60 amp breaker for the circuit, Doug could use a #10 copper conductor as an EGC - personally I'd use a #8.

Rob

[doug webb]

I appreciate the help from all of you and will be running the #6 wire. I will also be running a separate grounding rod to the subpanel. I am using a 60 amp breaker to feed the panel as I have nothing that pulls over 15 amps and no 220 requirements, at this time.. But who knows what the future holds? Thanks again for helping me stay safe........doug

[Ken Garlock]

Beep, wrong, but thank you for playing. (Dead poets society.)

I may be wrong, but as i understand it, you can only have ONE earth ground and that must be at the main service entrance. ANY subpanel must connect neutral and equipment ground back to the main distribution panel.

[Rob Russell]

Ken,

What is commonly required to feed another building like a shop or shed is a 4-wire feed. The neutral and grounding conductors are bonded only at the service equipment (typically the main panel). However, at the outbuilding, a ground rod or ground rods are also required and the EGC has to connect to those ground rods. The neutral and EGC are NOT bonded at the outbuilding.

Some localities want it done differently, so this is one of those "check with the inspector" types of things - see how they want it done.

Rob