Adding a 100 amp Square D Homeline Panel in Basement

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Old 09-12-17, 02:55 PM
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Adding a 100 amp Square D Homeline Panel in Basement

Hello All, First Time Poster here and I need some advice. I am installing a 100 amp Square D Homeline sub panel in the basement for future lighting and outlets. Will also run a 30 amp double pole circuit to the garage for a welder. Using my 200 amp main panel for power. I have four openings and will use two of them to power this sub panel. I am having this inspected by my local electrical inspector from Castle Rock, Colorado and had the first part of my project inspected. I ran about 28 feet of 1 1/2 inch conduit underground from the main panel and directed it to my crawlspace where I am going to mount the 100 amp sub panel on the wall between the crawlspace and the basement. The total length of run from the main box to the sub panel is about 67 feet. I bought 70 feet of 2-2-2-4 copper service entry cable. I am installing a 100 amp breaker in the main panel, and the sub panel has a 100 amp breaker in it. My question is: How do I run the ground wire in the main panel and the sub panel? None of the openings in either of the grounding bars are big enough for the #4 ground wire. Same thing for the neutral wire in the main panel. The sub panel has a big enough lug for the neutral, but nothing for the ground wire. Also, do I need to buy a grounding bar for the sub panel or is it already there?<br />
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Thanks in advance.
 
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Old 09-12-17, 04:31 PM
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SER cable is not approved to be put underground, even in conduit. You need to buy a larger add-on lug for the ground bar and neutral bar. You will most likely need a ground bar for the subpanel because the neutrals need to be isolated from ground.

Also for 100A you only needed #3 Cu.
 
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Old 09-12-17, 05:01 PM
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Most ground bars will accept up to a #4 without an adapter lug.
 
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Old 09-13-17, 07:10 AM
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Adding a 100 amp Square D Homeline Panel in Basement

What kind of wire do I need? The wire I bought is 2-2-2-4 copper wrapped in a plastic cover. Two blacks, a white and a bare #4 ground. That is no good for this application?
 
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Old 09-13-17, 08:07 AM
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There are a lot of types of cable; the exact designation should be printed on the jacket. If it's SER cable it cannot be used underground. If it's USE cable it cannot be used inside. If it's MHF cable is can be used underground, but must be in conduit indoors. If it's UF-B it can be used underground and inside.
 
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Old 09-13-17, 05:31 PM
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Assuming you have SER you can switch to individual wires of THHN/THWN of the same size conductors as in the SER using junction boxes for the run in the underground conduit.
 
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Old 09-14-17, 07:06 AM
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So I can use THHN wire in the underground conduit, run it into the crawlspace and a junction box, then use the SER cable to the sub panel? How do I connect those wires together?
 
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Old 09-14-17, 07:48 AM
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THHN/THWN has to be in conduit and can go underground. Use split bolts, Polaris connectors or splice/reducer. Split bolts and splice/reducers are the cheaper options and will need to be taped up well. The junction boxes will need to be a 12"X12" to have enough room for splicing.

Edit: You can use a 10"X10" jbox if you can find one. Basically the box needs to be 6 times the diameter of the entering conduit.
 
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Old 09-14-17, 11:18 AM
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While expensive the Polaris connectors are much easier and more foolproof than the hassle of split bolts.
 
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Old 09-15-17, 06:24 AM
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Thanks for all of your input, I really appreciate it. I had my local inspector come out and look at what I have done so far. He said that I should use THHN wire into a junction box, then go with the SER cable, just as was suggested here. Darn. Anyone need about 30 feet of 2-2-2-4 copper SER cable? I really want to ensure this is done safely and correctly, so I will bite the bullet and get the right stuff needed. Tune in later for updates...
 
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Old 09-15-17, 06:39 AM
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Don't feel bad. You are not alone. A lot of people get the wrong wire for underground use thinking if using conduit any wire will work.
 
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