Hot Tub Subpanel to Main wire run

This is a great forum! Thanks to all the knowledgeable posters who give their valuable time to help others. On to my first post.

I am installing a subpanel for a hot tub, which is situated on a covered, concrete porch at the NE corner of our home. The main service panel is located at the SW corner in the garage, about 80 cable ft away from the tub with all the twists and turns factored in. The cabling will have to run east from the main and exit the back of the garage, (25ft), from there it will go underground (or maybe not?) to get around to the porch (another 55ft).

The subpanel was supplied by the hot tub manufacturer and contains a 20A and 30A breaker, both of which are GFCI. Also supplied was a 50A non-GFCI breaker for the main panel.

The wiring connection diagrams are very clear, both from the main to the subpanel and from there to the hot tub. What is not clear to me are my options on physically getting the wires from the main to the subpanel.

The garage is unfinished, with all the wiring exposed. The existing cables exiting the main panel are NM type of varying guages. Nothing is run inside a conduit. So I ran to my local hardware store looking to buy enough 6-3 UF cable for the entire run (main to back of garage and underground to tub from there). But they were out of stock, so I puchased 4 ea 6AWG lengths of insulated stranded wires, marked as "MTW or THWN-2 or THHN or Gasoline and Oil resistant", with the intention of running them through a 1" conduit.

SO, after that lengthy background, here's my questions.

1) Can I use NM cable from the main to the back of the garage, and from there connect to individual wires inside schedule 40 PVC(via a condulet) for the rest of the run? Or would I have to run the PVC conduit all the to the main?

2) Is it against code to mix conduit types? ie using PVC or EMT coming down the back of the garage and then switching to rigid metal conduit so I only have to bury it 6" below my hard, root and rock filled ground?

3) Or, if I wanted to stay above ground for the outside conduit run, (I was thinking attached to the house just below the siding where it meets the foundation), is that allowable per code?

4) These are just my amatuer scenarios. How would a pro go about it? Tips or suggestions are most welcome. I'd be happy to supply a diagram if my descriptions are unclear.

 

You can use PVC, It should be schedule 80 PVC conduit. It is permissable to run this on the outside of the home. You will need a GFCI breaker in the main panel. You didn't need all the wires to be #6, but its ok. I would run the PVC all the way if at all possible and use LB's to go through any walls.
I did one the other day, and left the panel in the garage through the wallran pvc on the concrete to the crawlspace and then ran 6-3 to the spa panel.

 

Just out of curiosity,,, why would you need a gfci brkr in the main?

 

Thanks for the info. The sub-panel instructions actually only called for #8 wire from the main panel to the sub, and #10 and #12 respectively for the 30A and 20A GFI breakers from the sub to the tub.

But the stores #8 was only rated for 40A, so I went with the #6. Otherwise I stuck with the manufactures recomendations.

Is it OK to splice #6 wires at the LB box exiting the garage? And if so, can I use wire nuts or do I need something more heavy duty?

As to using a GFCI breaker in the main panel, is that really necessary, given that both of the breakers in the sub panel are GFCI? The standard 50A breaker is all the manufacturer called out.

 

You can't splice in the condulet-you'll need a nipple in the wall between the exterior condulet and a "deep" 4-11/16" square outlet box inside the garage. Use bolt-type connectors for #6 wire for the connections----do you have a Green Equiptment Grounding Conductor in the out-door conduit along with the #6?

 

Gotcha on the splicing. I'll run out and get the right stuff.

For the grounding conductor, I have green #6 of the same type (THWN) as my other 3 conductors going in the conduit. Do I need something different?

Thanks!

 

You could have used number 10 for the green,,, but I am still waiting for an answer from one of the code experts on the gfci question.

 

Dont get where you picked this up at, or did you misread it.

 

The 50 amp in the main does not have to be a GFCI, as long as the manufacture supplied subpanel/disconnect has the 20 and 30 amp breakers GFIC.
Usually a hot tub is wired with a double pole 50 amp GFI and that goes to the hot tub then internally it is seperated into circuits for the pump and heater. you dont need to worry about this scenario though.
I reccommend using a 6x6 PVC box and PVC pipe for the run.
If you use metal pipe dont look for a 4 11/16 "deep" box as opposed to shallow, all 4 11/16" boxes are the same depth.
Are you aware you must install a 120v outdoor recepticle that is no closer than 5 ft but no farther than 10 feet from the inside wall of the tub? wait.... this may have changed in the recent code I will check tomorrow.
Also you need to have a disconnecting means located within sight and at least 5 ft from inside wall, while remaining accessible for service.

 

aphares - he got that from joeh20's response to my post

I am finding that the #6 grounding conductor is too big for the ground bar terminal block. Back to the store I go... is #10 standard for this purpose? The schematic calls for #8.

For what it's worth, the wiring diagram supplied by the manufacturer (Watkins Manufacturing Corp, who makes the hot tub, not the sub-panel) clearly indicates that the main breaker is 50A NON-GFCI.

 

I see that now, It was me misreading. my fault.
MTGETS is correct on the main not needing to be GFCI.

 

hey aphares, as long as your on line tonight, you got your code book with you?
I am trying to remember the 120v recpt. rule, it has been a while since I did a tub.
But I am pretty sure you need to install a recpt. in those measurement, just out of reach but it is there for service and when the tub is being used for radios, tvs or whatever you dont have to string extension cords all over the place, am I dreaming or does this sound right to you? or anyone else too!!
It should be in NEC 680-40???? somewhere around there.

 

If it calls for number 8 use 8 then.

 

680.42 Outdoor Installations.
A spa or hot tub installed outdoors shall comply with the provisions of Parts I and II of this article, except as permitted in 680.42(A) and (B), that would otherwise apply to pools installed outdoors.


Part II. 680.22

(3) Dwelling Unit(s). Where a permanently installed pool is installed at a dwelling unit(s), no fewer than one 125-volt 15- or 20-ampere receptacle on a general-purpose branch circuit shall be located not less than 3.0 m (10 ft) from and not more than 6.0 m (20 ft) from the inside wall of the pool. This receptacle shall be located not more than 2.0 m (6 ft 6 in.) above the floor, platform, or grade level serving the pool.

Is this what your thinking of ?

 

Righty O, # 8 it shall be.

I do have an outdoor, GFCI receptacle 6ft from the tub. I have read that a hot tub is considered a pool as far as the NEC is concerned. As such, these are the codes that seem to apply:

-No poolside outlets <10ft. from water's edge (680-6a1)
-GFCI outlet. Minimum 10ft, Maximum 20ft from pool walls (680-6a2,3). '99 NEC.

So it looked to me like I have to move my receptacle another 4ft away to comply. At least to '99 code.

 

thats it!! when alot of people put in their own hot tub, they often forget about about that one, which can get into trouble with code violations from a home inspection, then they find there was no permit issued, yada yada.
Mandatory rules of the code are characterized by the use of the word "shall" NEC 90-5
No fewer than one means you must have one installed