sizing junction box

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iwirehouses

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I am running a 100 amp subpanel to a garage. The scenario goes like this...SER from the main panel. Where it exits the house, it will be in 2 inch conduit, underground, to the garage. My question is, what size junction box do I need to go from SER to 2 inch pvc? I will be coming in the top of the box with SER and going out the back with 2" PVC. 12"? 16"?
 
mdshunk said:
12" in any case. I do these all the time for 200 amp in 12x12x4 with no problem. Your 100 amp will be cake.
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If you're coming in the top and going out of the back the box wouldn't the box need to be larger than 12" to have a 6X dimension between the raceways?
 
infinity said:
If you're coming in the top and going out of the back the box wouldn't the box need to be larger than 12" to have a 6X dimension between the raceways?
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Maybe, depending on how you popped the knockouts in, but why would you do that? We're doing one cable and one raceway here anyhow.
 
so a 12" J-box? I guess I can LB and bring the conduit in the bottom of the box instead of the back. I'd rather go in the back tho, since the j box maybe be surface mounted and not flush mounted. Thes ser will be inside nailed to the Beam...not in conduit. $ #2 conductors will be in the conduit, with no sheathing.
What code prevents me from just coming in the house with 2" conduit, going into an LB, gluing a hub onto it, twist in a big cable connector, and exit the LB with SER? #2 isn't that big. You could splice it in a 2 inch LB and fold it over once. As far as I know, you can make a splice in anything that states the cubic inches.
 
The j box size is the least of your wories at this point.

If you are using aluminum #2 is too small. Either fuse it at 75 amps or run 1/0.

You can't use ser underground anyway so it doesn't matter what size you run..
 
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iwirehouses said:
#2 isn't that big. You could splice it in a 2 inch LB and fold it over once. As far as I know, you can make a splice in anything that states the cubic inches.
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Are we talking copper or aluminum? SER is only rated 60c in the 08 Code. If it's copper then you are good for 100 amps as long as the load is not greater than 95 amps.
 
The inspector told me to use #2 aluminum or #4 copper. Maybe I should down size the breaker for saftey reasons. Its not ser in the conduit. It's rated for underground use.
 
2-2-4-6- is small, I would use 1 1/4 pvc into a 60 amp NFD, then leave with Moble home feeder. slap a 60 amp breaker on it and go. leaves plenty of room for VD. 14kw should be more than enough for a garage
 
iwirehouses said:
The inspector told me to use #2 aluminum or #4 copper. Maybe I should down size the breaker for saftey reasons. Its not ser in the conduit. It's rated for underground use.
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If this were a service conductor for a dwelling then #2 aluminum would be okay but for a 100 feeder to a garage sub panel it is not.
 
A disconnect is a pretty good Idea. I think I will use a 60 amp disconnect to go from conduit to ser. then downsize the main breaker. No problems with that, right? Thanks
 
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