Wiring Plan for detached garage.

[Smokingthemidwest]

Good afternoon everyone,

Got a plan for wiring and wanted to run past you all to see if i am missing anything. I have a 200amp panel in the basement of the house. Detached garage that i would like to add a 100amp sub panel in. My plan is to use 2-2-4-6 mobile home feeder cable connected to a 90 amp breaker on the main panel. The total run would be 30' across the basement and out the wall then 50' underground to detached garage and then lb into the side of the building. I believe that with mobile home feeder cable needs to be in conduit is this correct? I have been reading a lot on this forum and understand to disconnect the neutral bonding screw and install separate ground bar for grounding. Then when wiring the new shop in connect neutral wire to the neutral bar and ground wires onto the new grounding bus that is installed, does this sound correct? Install 2 grounding rods outside the new shed with wire from ground bus? I have been looking on wire and cable .com for pricing of wire. Just wanted input before ordering wire. I have some experience wiring in the house so not a total newbie. Norther Illinois if that matters. Plan to use 2" conduit for the whole run. Open to any suggestions. Thank you in advance.

 

[75gmck25]

It sounds like you understand the basic requirements.

I used 2-2-2-4 AL SER to run across the basement (no conduit needed for SER inside) and then used a 12x12 junction box at the exterior wall to transition to 2-2-2-4 AL MHF. From there I ran 2" conduit through and down the wall, underground, and then up to the sub-panel at the garage. This put the entire run of MHF inside conduit. Two ground rods and separation of neutral and ground at the sub-panel.

Make sure you are consistent with the joint direction for the long conduit runs. Then you pull the cable across the joints so it does not catch on the lip of the conduit at each junction. Also use the spray lubricant. Makes it much easier.
Use pull boxes or an LB anywhere you need to change direction in the conduit, or maybe long sweeps if you have enough space. It won't want to pull across/through any simple 90 degree elbow.

 

[sparky 1971]

Good afternoon everyone,

Got a plan for wiring and wanted to run past you all to see if i am missing anything. I have a 200amp panel in the basement of the house. Detached garage that i would like to add a 100amp sub panel in. My plan is to use 2-2-4-6 mobile home feeder cable connected to a 90 amp breaker on the main panel. The total run would be 30' across the basement and out the wall then 50' underground to detached garage and then lb into the side of the building. I believe that with mobile home feeder cable needs to be in conduit is this correct?

It's a direct bury cable and only needs to be in conduit where exposed.

I have been reading a lot on this forum and understand to disconnect the neutral bonding screw and install separate ground bar for grounding. Then when wiring the new shop in connect neutral wire to the neutral bar and ground wires onto the new grounding bus that is installed, does this sound correct? Install 2 grounding rods outside the new shed with wire from ground bus? I have been looking on wire and cable .com for pricing of wire. Just wanted input before ordering wire. I have some experience wiring in the house so not a total newbie. Norther Illinois if that matters. Plan to use 2" conduit for the whole run. Open to any suggestions. Thank you in advance.

Everything looks good. The only thing I will add is to get a panel that has way more slots than you think you will need. There's absolutely nothing wrong with using a 200 amp 40 space main breaker panel fed form a 90 amp breaker. I wouldn't go to that extreme, but I'm not the typical GJ member. I'd probably opt for a 20 or 24 space 100 amp main breaker panel, maybe a 30 space if there was one in stock.

 

[Smokingthemidwest]

Thanks for the responses. I will look into the pull boxes and getting a larger panel (good idea since the inside isn't finished yet). Sounds like i have a decent plan to attack this wiring project.

 

[sparky 1971]

Thanks for the responses. I will look into the pull boxes and getting a larger panel (good idea since the inside isn't finished yet). Sounds like i have a decent plan to attack this wiring project.

If you're using 2-2-4-6 in 2", it will damn near pull itself. Don't go over 360° (I try not to go over 270°) in bends without an access point, which an LB is. If you can't get from the panel and across 30' of basement to an LB to turn down underground without a pull box, something is definitely wrong. If you plan on using conduit underground, you might want to consider boxes instead of LB's, but I'd just direct bury the wire unless the fill is rocky.

 

[dsp1]

I did something similar but since it was going to be completely enclosed in conduit used xhhw cable instead if I remember correctly. At the time Nassau cable had really good prices on it. My ground is rocky as hell so I really didn't like the idea of direct burial. Bending 2" conduit, even the exposed schedule 80 with a heat gun is pretty easy and leaves everything looking so much better.
He's right about the spray lube, that Klein foaming spray lube works awesome and is virtually no mess compared to the gels/waxes.
You should be good with the two grounding rods just make sure they are spaced appropriately apart. Also renting a big hammer drill from Home Depot, etc. along with the ground rod adapter will make the job very fast and easy, totally worth it.

 

[Codyboy]

It sounds like you understand the basic requirements.

I used 2-2-2-4 AL SER to run across the basement (no conduit needed for SER inside) and then used a 12x12 junction box at the exterior wall to transition to 2-2-2-4 AL MHF. From there I ran 2" conduit through and down the wall, underground, and then up to the sub-panel at the garage. This put the entire run of MHF inside conduit. Two ground rods and separation of neutral and ground at the sub-panel.

Make sure you are consistent with the joint direction for the long conduit runs. Then you pull the cable across the joints so it does not catch on the lip of the conduit at each junction. Also use the spray lubricant. Makes it much easier.
Use pull boxes or an LB anywhere you need to change direction in the conduit, or maybe long sweeps if you have enough space. It won't want to pull across/through any simple 90 degree elbow.

What did you make the splice with in the 12x12 box? If I can make a solid run I'll do that.
Also I will always put direct bury wire in conduit. Dig it once and done. I've seen a lot of direct bury go bad. Sure it might go bad in conduit too. Pull it out and pull in another.
Digging a whole new trench *****.

 

[Snapped-off]

What did you make the splice with in the 12x12 box? If I can make a solid run I'll do that.
Also I will always put direct bury wire in conduit. Dig it once and done. I've seen a lot of direct bury go bad. Sure it might go bad in conduit too. Pull it out and pull in another.
Digging a whole new trench *****.

Distribution block, Polaris lug, or split bolt would be good options.

Wire nut if you're feeling froggy.

 

[75gmck25]

For the splice in the 12x12 box I used insulated Polaris-style two port multi-tap wire connectors . My junction box is inside the house, so I didn't need any weather protection.

Polaris brand connectors are very expensive (like $15-$20 each), so I may have found a similar brand, but I don't recall for sure.