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Running 2 Circuits in Same Conduit - 1/2" LNFC - Is This Permitted?

Running 2 Circuits in Same Conduit - 1/2" LNFC - Is This Permitted?

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Old 12-01-17, 09:57 AM
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Running 2 Circuits in Same Conduit - 1/2" LNFC - Is This Permitted?

I was going to add 1 20A receptacle at my outdoor subpanel, but I decided that I'd like to add 2 if possible. I was planning to house them in a 2-gang weatherproof box. Can I run two separate circuits in the same conduit, or does each one need to be in its own? I am using 12AWG THHN/THWN with 1/2" LNFC. I was thinking about using 3/4", but it appears that 1/2" is acceptable. Thanks for any input.
 
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Old 12-01-17, 10:42 AM
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You can share the same 1/2" conduit. The two circuits can share the same green or bare ground, but should have separate black hots and white neutrals. You can use either solid or stranded THHN.
 
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Old 12-01-17, 10:52 AM
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Thanks for your response. I have the THHN with the hot, ground, and neutral pretwisted together. Is itís okay to run 2 grounds and pigtail them all together in the weatherproof box?
 
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Old 12-01-17, 10:58 AM
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Yes as long as all of the grounds are connected together.
 
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Old 12-01-17, 11:35 AM
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You are also supposed to group the wires together or mark them in the box and panel so that they you know which neutral goes with which circuit.

Note you could also just go with a single neutral and do a MWBC off of a double pole breaker.
 
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Old 12-01-17, 05:49 PM
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THHN can not be used outside. You need THWN. Most wire BigBox calls THHN is actually dual rated THHN/THWN.
 
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Old 12-01-17, 07:13 PM
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Since 1977 when I first became familiar with THHN wire I have never seen any of any size that wasn't dual rated as THHN/THWN-2.
 
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