I just want to make sure I am purchasing the correct wiring for a hot tub that was given to me. It's a 3-wire tub but I plan on plan on pulling 4 for when this one dies.

From the main panel (in the garage) the shortest path to the pad is through the basement above the drop down ceiling, outside under the deck, then 18" under ground for 12' to a disconnect/GFCI box mounted on a wood post, then back underground 10' more to the concrete pad where the hot tub will be.

Given that routing, my understanding is 6/3 NM-B will be fine inside (bare ground). Then in a junction box before going outside we'll switch to four #6 THHN/THWN wire protected in pvc conduit under deck and underground.

Just checking that my shopping list is accurate.

I guess another question is if I used the #6THHN/THWN wire inside it would also need to be protected in something? correct?

Thanks for the help

 

Any time you run individual THHN/THWN conductors they must be in conduit whether they are inside or outside. The conduit can be EMT, IMC, Rigid heavywall or PVC, but never PVC plumbing pipe.

 

Yippee! Your wooden post is a "seperate structure." You must use a grounding electrode. If you pour concrete over rebar you must use that electrode. Otherwise, it's ground rod time!

PVC is cheap and easy. 3/4 inch schedule 40 is ok. Switch to 1 inch sch. 80 above ground. Esp. at the post for wild rider mower mishaps. 1 inch the whole run for easier wire pulling. 18" to top of pipe means dig a 20" trench.

Use electrical duct seal any time a conduit ends in a box or panel.

Ground rod tips: copper is better. Use an acorn clamp. Dig a 6" hole. Pound rod thru bottom of hole to 1" under grade. When you fill in the hole ground rod will disappear! Put the clamp on, tight, without the wire, before you pound. Otherwise you'll never get it over the mushroomed end. Sleave the ground rod wire in PVC above ground.

Post tip: Use a plastic fence post for that never will rot, designer look.

 

BTW, your wire has lots of extra capacity for lights, radio, bug zapper, surge suppressor, etc. Use the same GFCI breaker for the spa in a MLO(main lug only) panel with a couple or four extra spaces. Expandability and choices for the future.

 

I'd use the 60A GFCI beaker in the main panel, so the entire subpanel is GFCI'd.

 

Good way to think safety Justin. Challenges are:

GFCIs become more sensitive the longer the circuit. It's a long way to walk if the breaker nuisance trips.

His spa probably requires a 50A GFCI.

Some spas require two double pole GFCIs. A 30A and a 20A.

If he pipes the run the whole way, he could legally use a 70A breaker at the main.

A GFCI convenience outlet is required within 20 feet of the water's edge, but no closer than ten feet from the water's edge. I doubt he has one. He'll need to run one from a single pole breaker at the post panel.

GFCIs in series don't play well together.

 

Wow! Great info. Yes a single 50a breaker is required. Thanks for the info on grounding my post. So, for the gfci outlet 10-20' from water I should be able to mount that on the same post as the gfci disconnect box.

 

Sure. Just mount it in a weatherproof box with an in-use cover.

 

Interesting. Never heard nor experienced that before.

 

Wow! My projects take FOREVER!!! Anyway, I finally got the wire (thhn 6 gauge red, white, black, 10 gauge green) ran through conduit through the house then outside and down the side of the house, in a 20" deep trench and into my separate structure (post) holding my hot tub panel. From the panel it goes back underground for another 12' to where the hot tub will eventually land.

I had an electrician come and make the connections in the main panel in the house and the hot tub panel out back. I am trying to attach a picture of the connections made in the hot tub panel to make sure they are as they should be.

The wires on the left are from the house. Right, to the hot tub and center to GFI outlet on same post. There's an extra green (lighter green from hot tub) that is connected but shouldn't be. That was run as a bond per hot tub manual but it appears bonding is not longer required for portable hot tubs.

One thing in particular is I put in an 8' ground rod but the electrician didn't connect anything to it.

I had such a great response from the first part of this thread I thought I would try to continue it on in hopes the previous posters would contribute again.

Thanks

 

Romex should not be used for the convenience recp. if this is outside, also it would be wise to use a 20 amp breaker for leaf blowers weed whackers and lawnmowers.

 

Ok, i can change the romex. It runs about 12" in my enclosed "post" which amounts to two 2x4's sides with front and back panels. All wires run from under ground inside my "post" to and from the Hot tub panel

 

Use uf-b or conduit.........

 

ok, i'll rewire the gfi outlet with uf-b. What about the whole post is a seperate structure but its not connected to the copper ground rod I drove into the ground

 

It should be connected to the ground bar in the subpanel on the post. I would use #6 bare copper.

 

ok, i wasn't sure if connecting the green ground from the main panel and a bare wire to a new ground rod would cause problems or if that was the way it was supposed to be done.

Am I correct that I should put another ground rod at least six feet from the one I've already put in the ground and connect the two?

Thanks again for all the replies

 

That's the way it should be done.

Yes. Use one piece of #6 bare copper to connect to both rods.

 

Check with your AHJ, it's not a NEC requirement.