Spa Wiring

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Old 12-16-07, 07:40 PM
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Spa Wiring

I am wiring up a spa. Not to be rude, but I do plan on doing this myself; so please spare me the, "if you have to ask, hire a pro...." I would however really appreciate advise.

Here is my plan:
-Install a 40 AMP double breaker in my main panel. (Just upgraded to 200amp, so there is plenty of spaces.)
-Run NM cable ~10 on house interior
-Pop through the wall, install a box with my 40amp GFCI.
-Run SCH40 pvc conduit ~50ft to where the tub goes. The tub is going on top of a preexisting concrete slab. I have hollowed out underneath the slab to run my conduit under the slab.
-Run the last 6' in liquidtight conduit. This includes passing up through the slab
-Bury my PVC conduit 24-30" deep.
-Pull 4 #6 THHN wires.
-Hook it all up.


So, does anybody see any major flaws with the plan? Here are my specific questions:

1) I only see liquidtight in 1/2" and 3/4". Do I need to reduce to 3/4" for my last 6'?
2) How many expansion joints do I need for the PVC?
3) It is OK to used PVC conduit for exposed installation (e.g. for the run from the GFCI box down to the ground)?
4) Is it OK to connect the 3/4 liquidtight to the PVC under the concrete slb, or will the inspector want to see it exposed?

Thanks a lot. I really appreciate any response.

Jeff (in Denver)
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Old 12-16-07, 09:13 PM
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Wow, that's quite an introduction to your question. You must be getting a lot of hostile advice on other forums. I hope your luck is better here.

Have you already got the spa? Many spas are wired with 50-amp or 60-amp circuits, but perhaps you have a small spa that only needs 40 amps. Be sure to read the installation requirements carefully. I'll assume you already have, and that the spa manufacturer specifically calls out for a 40-amp breaker.

You said, "Run NM cable ~10 on house interior". Is there an implied "feet" after the 10?

#6 THHN is fine, as long as the neutral is white and the ground is green, and the THHN is dual rated THWN.

Schedule 40 PVC is sufficient only if the conduit is not subject to physical damage. Otherwise, use schedule 80.

You didn't mention voltage. I assume your 40-amp GFCI is a 240 volt breaker. And I guess your spa doesn't need any 120 volt power. But still, code requires a convenience 120-volt receptacle near the spa.

The inspector will want to inspect before you pour the slab.

There are a lot of bonding requirements to meet. Make sure you read the installation instructions carefully.
 
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Old 12-17-07, 08:23 AM
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Thanks for the reply. I supose I did come on a little strong at first...

Yes, I menat 10'

The Spa only needs 240V/40A. I want to run #6 though, so that if I get a new spa than the wiring can handle 50A.

The slab is already there from the previous owner. I have hand augered underneath it, and plan to drill through it to bring the conduit up through it. Will this be a problem?
 
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Old 12-17-07, 08:39 AM
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#6 is a good plan.

No, it shouldn't be a problem going under the existing slab.
 
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Old 12-17-07, 11:44 AM
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A couple of things to check

First of all, I am not an electrician, but did receive a lot of help from these boards when I hooked up my spa. I will not give electrical advice but just some practical items you might want to run by the pros on this board and perhaps your local inspector.

When I poured my pad, I had to run a solid copper wire (#8 if I remember correctly) from the reinforcing mesh to the panel in the spa to act as the bonding wire.

While I understand you have a preexisting pad, I would suspect you still need to get a bond wire into the reinforcing mesh. Again, I'll let the pros beat me up if this isn't an issue.

My other issue is your plan to come up under the slab. Are you trying to come up next to the spa or under the spa? I wasn't clear on your plan. Coming up under the spa will cause all kinds of problems as there isn't a lot of room inside of the cabinet.

Let me know how it works out and enjoy the spa.
 
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Old 12-17-07, 12:09 PM
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I plan on coming up into the cabinet. I can make it work with my current tub, but it sounds like it might coause problems if I replace the tub?

Should I come up through the slab, and enter the cabinet with a LB conduit body or similar?

Thanks for your input!!

Jeff
 
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Old 12-17-07, 05:16 PM
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Originally Posted by DenverJeffro View Post
-Pop through the wall, install a box with my 40amp GFCI.
-Run SCH40 pvc conduit ~50ft to where the tub goes.
Is there a requirement for a disconnect, and does it have to be within a certain distance? Is there a code requirement for a convenience outlet?
 
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Old 12-17-07, 05:47 PM
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Disconnect must be more than 5' but less than 10'. One outlet for servicing also more than 5' but less than 10'
 
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Old 12-18-07, 05:23 AM
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Your Call

Originally Posted by DenverJeffro View Post
I plan on coming up into the cabinet. I can make it work with my current tub, but it sounds like it might coause problems if I replace the tub?

Should I come up through the slab, and enter the cabinet with a LB conduit body or similar?

Thanks for your input!!

Jeff

The guts (piping, motors, insulation etc.) of each brand of tub are different and even vary within models of each manufacturer, so while you might be able to come in under the bottom of this current model tub, your next one might have something blocking this entry point.

I wouldn't let this deter your current installation because you shouldn't be thinking that this tub will fail anytime soon (unless you were given a used tub and then you have to wonder why it was given away!!!).

Even if you get a different tub down the road, you could always reroute the wiring at that time and even if you go in through a side access on the tub at this time, it might not work for a tub purchased down the road.

My only concern for your plan of going in from the bottom is that you triple check the entry point so you don't come in under a motor or other obstruction inside of the tub cabinet.

I regards to the disconnect, I was under the impression that the disconnect had to be "within sight" of the tub, not between 5 and 10 feet as Tolyn Ironhand stated. I'll let a pro weigh in on that.
 
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Old 12-18-07, 08:43 AM
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service disconnect has to be within sight

the convenence 125v gfci recepticle outlet is no closer then 10' no further then 20' from the inside wall of the tub.

no more then 3' of liquidtight can be used to connect to the spas panel board. so you run the pvc under, stub up, then install a female threaded adapter on the pvc and then install the liquid tight adapter to that and the spa panel. Use it as a flexable chase. Make sure you leave your wires long enough when you pull them to chase thru the liquid tight and into the spa panel for hook up.

BTW you can put your 240volt GFCI breaker in your main panel, then pull the wires to the weathertight service disconnect (non fusable) then to the spas panel board

Also you ground wire must be insulated No Bare Ground
 

Last edited by brewaholic; 12-18-07 at 09:10 AM.
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Old 12-18-07, 08:45 AM
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"I regards to the disconnect, I was under the impression that the disconnect had to be "within sight" of the tub, not between 5 and 10 feet as Tolyn Ironhand stated. I'll let a pro weigh in on that."

Sgt.
That is more or less correct. According to the provisions of article 680 (Pools, Spas, hot tubs and fountains), I am working from the 2005 NEC here; A disconnect must be located within sight, but no less than five feet horizontally from the tub. Now I have been in discussion with several fellow electricians, as to what with in sight refers to, and we all basically agree that it is within 50 feet and clearly visable. But, of course, no less than five feet from the tub.

Jeff
Allow me to give you some advice, get a copy of whichever year of the NEC your locality enforces and read article 680 very carefully. There is a lot of material there and it can get a might confusing. I imagine from your opener that you have met with a lot of resistance to you doing this work your self. There is good reason why some of us pros are so apprehensive about assisting. I have nothing against people doing things themselves, but I do ask that you do your homework first. Electricity and water have a very contemptous relationship and, at the end of the day, it's your family's safety, your friends safety(and ultimately your ass) at stake here. Take your time and make sure that you do it right.
Good luck and be careful
Ian
'getting down off my soap box now
 
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Old 12-18-07, 01:57 PM
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1) I only see liquidtight in 1/2" and 3/4". Do I need to reduce to 3/4" for my last 6'?
2) How many expansion joints do I need for the PVC?
3) It is OK to used PVC conduit for exposed installation (e.g. for the run from the GFCI box down to the ground)?
4) Is it OK to connect the 3/4 liquidtight to the PVC under the concrete slb, or will the inspector want to see it exposed?
A-1. go to the electrical supply house they have it in larger sizes

A-2. I have no idea what you mean by expansion joints?

A-3. Yes you can have the pvc schedule 40 exposed from the disconnect/panel down the wall into the trench, as long as you strap it properly and it's not in a driveway or the likes.

A-4. No you want to push a pvc 90* sweap down under the slab in the trench, then where you drilled your hole in the slab, push a glued piece of pvc down from the slab into the 90* sweap.

like mentioned by sarge if you have 10 gauge wire mesh/rebar in the poured slab, you will need to run a bonding ground wire to that and secure it with a split bolt connector or the likes. #8 gauge bare copper if not exposed to physical damage, or # 6 gauge if exposed.
 
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Old 12-18-07, 02:15 PM
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Ian- Your advice is taken to heart. I do plan on having this permitted/inspected as well. Its no place to mess around...

The 5-50ft for the disconnect was what I was interpreting. Same with the 10-20' for the convience outlet. I am planning on having the disconnect on the house, right at the 50' mark.

brew-

I like your idea using a sweep to stub out from the slab. Might take a little more screwwing around (and more augering), but it should work better and help keep me under the flexible conduit requirement.

The expansion joints are a coupling w/ 2 gaskets. The 2 halves of the coupling can slide in/out and remain seeled. That allows expansion/constraction of the PVC with the changing temps w/o building up stress. Maybe at 30" depth this is not needed?

I thought that up to 6' of flexible conduit could be used to connect to the spa. I'll have to look in the NEC for a refrence. I went someplace else last night, and did find the 1" liquidtight.


Thanks agian everybody.
 
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Old 12-19-07, 10:11 AM
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jeffro

never used that type of coupling on electrical apps.

the grey electrical schedule 40 pvc comes in 10 foot sticks with a molded bell (coupling) on one end for joining the sticks together.

I don't know if you have a code about depth and frost line requirements where you live?? Around my parts we just dig a 24" trench and glue the lengths together.

we use a torch on a 20# propane bottle and make our own bends/sweeps when needed but you can buy them pre made and just glue couplings on either end.

The couplings that I have seen that you sound like you are describing are plumbing pvc repair couplings. They are used for making repairs on underground pvc water or waste pipe. They expand so you can just cut out the bad part of the pipe and slip the coupling in between the two sections, then expand it once glued to complete the repair. they are rated to handle water pressure.
 
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Old 12-19-07, 03:06 PM
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here is some info on the expansion fittings:
http://www.carlon.com/Installation_T...IT-ISEXPJT.pdf

Looks like they are not needed. I have a short enough run and temperature change at that depth should not cause a problem.
 
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