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Based on the answer to my recent question "How to wire a 240V disconnect panel for spa that does not require neutral", I need to run another wire from my main service panel to my spa disconnect panel to serve as neutral.

Current Situation

I began wiring already and noticed my problem halfway. Oops.

  • I have three 6 AWG wires running from my main panel to my 60A spa disconnect panel:
    • hot red
    • hot black
    • grounding green
  • All are THHN/THWN-2 rated
  • In locations where conduit is required, I'm using 3/4" liquidtight flexible nonmetallic type-B

Proposed Fix

Re-purpose the grounding wire and make it my neutral instead. I would then need to run an additional wire for ground.

My goal is to run the new grounding wire in the same 3/4" conduit I already have if possible. After reading NEC table 250.122, the grounding wire requirement for a 60A panel is 10 AWG copper.

I would put white tape (and a note) around the re-purposed green wire to prevent future confusion.

Questions

  1. Can the grounding wire be bare if it's in conduit, or does it also require THHN/THWN-2? There are wet locations along the run.
  2. Can I run the new 10 AWG grounding wire in my 3/4" conduit which already has three 6 AWG wires?
Community
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Scott Lin
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1 Answers1

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You CANNOT re-purpose a green wire smaller than #4 as a neutral, even if it is insulated. Is the #6 ground green all the way? If so running a new neutral in this case is your only option.

The ground wire in the outside portion of the wiring for a hot tub in conduit CANNOT be bare. It MUST be green insulated.

I would use a GFI in the main panel and a regular breaker in the spa disconnect. Easy-peasy.

Speedy Petey
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