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I have an outdoor 240v disconnect with 6awg cable (red/white/black/green) running from the main breaker to this disconnect box. There's a 110v GFCI-protected branch circuit that goes to some wall sockets. The 240v is for a hot tub about 6' away.

We're building a deck and now want to move the hot tub about 20' further away. I do not wish to buy and pull all new cable from the main breaker to the new location, so my idea is to swap out the disconnect and replace it with what amounts (I guess) to a junction box, except the 4x 6awg cables would be joined inside (no switches). Except I'm struggling to find a suitable box - well, I can find boxes, and I can find butt splices, but I would feel more comfortable with four sets of terminal blocks that I just screw the eight wire ends into, and those terminal blocks be attached to the box.

Any suggestions please? Picture attached. Ignore the simplified wiring for the GFCI block: it's wired properly, honest! New intermediate box will also be grounded

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    It sounds like this is a really a small subpanel, or at least it should be. Upload a picture of the current box, showing wires, switches, breakers, etc. – manassehkatz-Moving 2 Codidact May 11 at 18:53
  • Search 6-20 AWG din rail assembly – NoSparksPlease May 11 at 19:59
  • @manassehkatz-Moving2Codidact it's this one, wired identically: spadepot.com/wiring-hot-tub-spa.htm . So between the home service panel and the MW GFCI Load Center would be the new box, just a simple (!) splice. Physically the new box would be where the old box is now, with the old box moved 20' further away. – GeoffM May 11 at 20:59
  • I take it the box needs to move because the old location is no longer in sight from the spa? – ThreePhaseEel May 11 at 23:19
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You can do it with din rail terminals a company called automation direct usually has good prices and you could get the rail the 4 terminal blocks ( knt2blu) these work 12-2 awg ~19$ for 10 terminals. With a terminal block style you need the rail that holds the terminals and the end blocks and clamps.

I would suggest you get 4 Polaris style splices (97102) a Morris brand I got for ~5-6$ and it can handle 14-4 awg easier install and really easier to use in this case. Big box stores and electrical stores carry the Polaris style and they would be all you need.

I would just use wire nuts with the 120v wiring, in both cases

Where you run into problems is on the box fill #6 wire is 5 cu inc each and the number 12 is 2.25 cu inch plus clamps at 5 cu inch, you only have 4 grounds so the largest possibly a #10 in the 6 awg cable but I calculate it at #6 for worst case.

49 cu inch total since the box is outside it needs to be a 3R type box (you said you had the box I just ran the numbers because DIY almost always get hit here.)

The wire nuts and splices are included in the wire size. Up to 4 grounds we only count the largest. Clamps we only count 1 for the largest again. Just to make sure your box is at least 49 cu inch, if the ground in the cable is #10 you can subtract 2.5 cu inch because #10 is 2.5 not 5.

Updated answer: suggested scrapping the 6’ wip from the disconnect and just running a new one. The disconnect needs to be at least 5’ away from the tub and within 50’ + within site to meet code. It looks like this will be the least expensive option.

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  • Thanks. I was hoping to find an electrical box that already had DIN rail fittings, much like the spa disconnect box I bought had the rails and breaker mounts already fitted. – GeoffM May 11 at 20:56
  • I do this for a living and can tell you the only way to get a box with built in DIN will be to pay about 10x (look at how much spa boxes cost). Sure I build up Hoffman boxes and terminal strips when there are a bunch of cables being spliced you will still need to purchase the correct size terminals connectors to fit on the DIN rail. To do what you asked I would use Polaris. I would change how you are looking at it leave the disconnect where it is and run a new cable from the disconnect. the disconnect can be up to 50’ away it just can’t be closer than 5’, so you scrap a 6’ wip you still save. – Ed Beal May 11 at 22:16
  • Woah, I thought the requirement was 5-10' away but in its original context it was 5' minimum (correct) and 10' suggested (NOT maximum). D'oh. So my hot tub being 25' away and within line of sight meets code. Excellent! What a wild goose chase that was. Thanks for redirecting me! – GeoffM May 11 at 23:00
  • Some times we look two deep into things because we can’t see what is going on, glad we could help. I will update the answer. – Ed Beal May 11 at 23:36
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The cheapest couplers are other things

Generally, couplers are expensive for what they are, and your desire for fixed, attached couplers won't be well supported (not least because wire bending radius rules makes it awkward/complicated).

So the most expedient way to connect four #6 wires to four other #6 wires, with isolation and fixed down in a box, will be to use a disconnect switch. Which you say you already have, so "that was easy" :)

You glossed over this part pretty fast, so I'm not sure if you are handling this properly, but a 15A receptacle is only allowed downline of a 15A or 20A breaker, you can't tap off a 50A line and bring it out to a common receptacle. You fix that by using a subpanel at that location.

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  • Probably me not explaining (and definitely not drawing) it well enough. The plan is from spadepot.com/wiring-hot-tub-spa.htm. I suppose a disconnect between the main panel and the (relocated) disconnect would work; just seemed overkill. But... if it works... if it's simple... yeah. – GeoffM May 11 at 20:47
  • @GeoffM Of course it's overkill. All you want is four pair of #6 lugs. But when all you want is a disconnect for a shop subpanel, a main breaker is overkill; it just works out as the cheapest because of economies of scale. What the Spa Depot page suggests is fine. – Harper - Reinstate Monica May 11 at 21:19

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