Spa Sub Panel- Also grounding Question


  #1  
Old 03-18-15, 07:45 AM
M
Member
Thread Starter
Join Date: Mar 2015
Location: United States
Posts: 6
Received 0 Votes on 0 Posts
Spa Sub Panel- Also grounding Question

Hello! My first question/thread. Here goes. I will be installing a 60 amp spa sub panel in my detached garage roughly 30' from my house, 60' from the main panel. I have a few questions.
1) The hot tub calls for 4 wire. So I should use 6/4, local electrical supply is telling me they only have MC in that size, (I think there would be a problem running that in underground conduit). Anyone know of any other type of 6/4 that would be available? (trying to go the cheapest route). I'm not sure local code if I can run direct burial, so since I'm not sure I'll just conduit it. Also, what size wire to the grounding rods for this panel?

2) The wire from the hot tub is 6/4, hitting the neutral and ground in the sub panel. Can I run 6/3 from the sub panel to my main panel? If so I run the ground to the ground bar, not the neutral to the ground in the main panel? I'd like to use the easiest wire to work with/ the cheapest. I really don't want to use MC, and I'm not all to familiar with the different jackets/types of wires on these larger sizes.

My other question is regarding grounding. I just upgraded my main panel to a 200 Amp panel. I drove in 2 ground rods, and was going to run one 3 awg bare copper from my panel to the ground rods, daisy chaining (no splices or cuts, just a direct run) from the one ground rod to the other. I briefly spoke to the inspector and he told me I need to double ground them. What does this mean? Go from one ground bar to the ground rod, and the other ground bar to the other ground rod?
Any advise would be greatly appreciated!
 
  #2  
Old 03-18-15, 08:09 AM
ray2047's Avatar
Member
Join Date: Mar 2006
Location: USA
Posts: 33,575
Received 15 Votes on 13 Posts
I will be installing a 60 amp spa sub panel in my detached garage roughly 30' from my house, 60' from the main panel.
You can not have two sources of power to a detached structure. If the garage has power for lights and receptacles that power source will have to be abandoned. You will need to install a subpanel in the garage for the garage circuits and the spa panel.
The hot tub calls for 4 wire. So I should use 6/4,
No, 6-3, ground doesn't count.

Unfortunately your plan is not even close to correct so I will leave your other questions unanswered for now It sounds like first we need to plan to run a subpanel in your garage. To do that we need to know about the loads in the garage and the actual power requirements of the spa.

Notes: MC is not always rated for wet locations. Conduit outside is always consisted a wet location. MC is not run in conduit. Best practice individual conductors are run in conduit. You can also use direct burial cable such as URD or UF-b with out conduit (except for short sleeves where it needs protection).

I would suggest you buy the book Wiring Simplified and study it so you know the basics of what you need to do.
 
  #3  
Old 03-18-15, 08:18 AM
M
Member
Thread Starter
Join Date: Mar 2015
Location: United States
Posts: 6
Received 0 Votes on 0 Posts
There is already a panel in the garage. I can mount the panel on the outside of the garage, and get around this no?? OR attach the panel to my house (avoiding the extra ground rods), and run the feed underground to the spa 30' away?? If I do that I can tap off my garage panel for the convenience outlet.

So use 6/3, then just use the 2 hot, and neutral, and cap off the ground wire from the spa??

See attached pic showing electrical requirements of spa. Name:  IMG_0075.JPG
Views: 819
Size:  36.9 KB
 
  #4  
Old 03-18-15, 08:21 AM
ray2047's Avatar
Member
Join Date: Mar 2006
Location: USA
Posts: 33,575
Received 15 Votes on 13 Posts
I can mount the panel on the outside of the garage, and get around this no??
Yes but the feed to that panel should be individual conductors in conduit. It can not be UF-b because outside you need an insulated ground for a spa. MC is really not something to even consider.
So use 6/3, then just use the 2 hot, and neutral, and cap off the ground wire from the spa??
No. The panel must have an EGC and a GEC (ground rod) if on the garage. If on the garage the EGC must be green insulated so cable can't be used. If on the house no ground rod (GEC) but if the spa is outside you need an insulated EGC.

Have you considered connecting the Spa panel to the garage sub panel?

Note all sub panels require an EGC and bonded ground bar. If 120/240 they also require an isolated neutral bar. Your Spa panel is 120/240 so both will be required.
 

Last edited by ray2047; 03-18-15 at 08:42 AM.
  #5  
Old 03-18-15, 08:51 AM
M
Member
Thread Starter
Join Date: Mar 2015
Location: United States
Posts: 6
Received 0 Votes on 0 Posts
I would really like to avoid individual conductors in conduit all the way to the panel.. I do not want to rip up my entire basement ceiling to mount conduit
 
  #6  
Old 03-18-15, 09:11 AM
Geochurchi's Avatar
Member
Join Date: Nov 2012
Posts: 5,583
Received 154 Votes on 140 Posts
What size is the panel in the garage? is it fed by conduit now?
Geo
 
  #7  
Old 03-18-15, 09:13 AM
M
Member
Thread Starter
Join Date: Mar 2015
Location: United States
Posts: 6
Received 0 Votes on 0 Posts
Its a 100 amp panel. BUT its only being fed with like 10-3 and a 20 amp circuit. There's only two receptacles and 3 lights out there...
 
  #8  
Old 03-18-15, 10:57 AM
M
Member
Thread Starter
Join Date: Mar 2015
Location: United States
Posts: 6
Received 0 Votes on 0 Posts
I know I need an insulated green, which is why I said I'm going to use 6/4.. My question was, I know I cant use MC, what other type of cable I could use?????????? I'm trying to avoid individual conductors, I dont want to tear up my basement ceiling to install conduit..
Ray, you may be trying to help but your arrogant comments like read a book, or my whole plan not even being close to correct are really just unnecessary.
 
  #9  
Old 03-18-15, 04:28 PM
CasualJoe's Avatar
Member
Join Date: Jan 2010
Location: United States
Posts: 11,151
Received 164 Votes on 147 Posts
my whole plan not even being close to correct are really just unnecessary.
But it was an accurate statement. I am not a spa expert, but unless I am mistaken, you need and insulated grounding conductor in your feeder to the spa panel as well as an insulated grounding conductor to the spa. That eliminates all non-metallic cables. PVC jacketed MC cable can be used outside and it does have an insulated grounding conductor.

your arrogant comments like read a book
This isn't arrogant at all as you don't appear to have a good knowledge of spa wiring. Whatever you decide to do, you should also consult your local AHJ inspector for his approval before you take out your permit and get started.
 
  #10  
Old 03-18-15, 05:08 PM
ray2047's Avatar
Member
Join Date: Mar 2006
Location: USA
Posts: 33,575
Received 15 Votes on 13 Posts
use 6/4.
No, as stated before 6-3, white, red, black, ground. ((6-4 is either white, black, red, blue, ground or white, gray, black, red, ground.) Not being a prick but if you are ordering cable they may be telling you they don't have it because you are asking for something not commonly stocked.
I dont want to tear up my basement ceiling to install conduit.
You don't have to. Inside you can use cable with bare ground.
 
  #11  
Old 03-18-15, 05:23 PM
CasualJoe's Avatar
Member
Join Date: Jan 2010
Location: United States
Posts: 11,151
Received 164 Votes on 147 Posts
You don't have to. Inside you can use cable with bare ground.
I don't think so, Ray. I am not positive, but I think this has been discussed before and the feeder to the spa panel must also have an insulated ground. He could use MC cable inside though and it would have an insulated ground. Hopefully, one of the spa experts will weigh in on this issue.
 
  #12  
Old 03-18-15, 07:15 PM
ray2047's Avatar
Member
Join Date: Mar 2006
Location: USA
Posts: 33,575
Received 15 Votes on 13 Posts
I don't think so, Ray. I am not positive, but I think this has been discussed before and the feeder to the spa panel must also have an insulated ground.
The answer is somewhere in this quote from the web but beyond my skill level
Indoor installations of spas and hot tubs must also comply with Parts I and II of Art. 680, except as modified by Part IV. You can use any Chapter 3 wiring method for indoor spas and hot tubs [680.43].
And this from a previous post here which my answer was based on. Source post #7 http://www.doityourself.com/forum/el...ml#post1854096
The cables can run through the interior of the house. Outside the house you need the conduit and THHN with a green insulated ground wire. Conduit should be 3/4" minimum. Again this is why a panel mounted on the exterior wall of the house is convenient: romex from main panel to spa panel on outside wall, conduit from outside subpanel to tub.
 

Last edited by ray2047; 03-18-15 at 07:40 PM.
  #13  
Old 03-19-15, 06:19 AM
M
Member
Thread Starter
Join Date: Mar 2015
Location: United States
Posts: 6
Received 0 Votes on 0 Posts
I definetely dont think I can use un-insulated ground anywhere along the way.. I'm just going to run MC inside the house, splice it to individual conductors outside. This is a small question, would be easy to do it either way. Code wise, can I run the MC through the outside wall into a junction box on the outside wall and splice it there, or should I put the junction inside and run the individual conductors through conduit in? Obv. the former would be preferred over the latter.
And 3/4" conduit is going to be a little tight on 4 6AWGs, definetely going with 1"...

Also, never got an answer on my main panel double grounding. Run one wire from each ground bar to each rod, individually??
 
  #14  
Old 03-19-15, 07:16 AM
pcboss's Avatar
Forum Topic Moderator
Join Date: Jul 2002
Location: Maryland
Posts: 15,389
Received 148 Votes on 131 Posts
IMO there is not enough knowledge for most DIY to take on a spa or hot tub project. The rules are rather complex and vary depending on if this is a feeder or a branch circuit. Some of the rules for a feeder call for a metallic conduit that rules out cables. A cable can be used for a branch circuit.

The issue of the potential need for abond grid has also not been addressed. Also the needed 120 volt convenience receptacle close to the tub.
 
  #15  
Old 03-19-15, 08:10 AM
ray2047's Avatar
Member
Join Date: Mar 2006
Location: USA
Posts: 33,575
Received 15 Votes on 13 Posts
Ask your inspector what he wants.
 
  #16  
Old 03-19-15, 09:59 AM
Geochurchi's Avatar
Member
Join Date: Nov 2012
Posts: 5,583
Received 154 Votes on 140 Posts
How difficult would it be to refeed the existing 100amp panel in the garage,then take your branch circuit from there to the spa.seems like a cleaner installation.
Just a thought
 
  #17  
Old 03-19-15, 06:32 PM
CasualJoe's Avatar
Member
Join Date: Jan 2010
Location: United States
Posts: 11,151
Received 164 Votes on 147 Posts
Also, never got an answer on my main panel double grounding. Run one wire from each ground bar to each rod, individually??
You may have to ask the inspector what he means by double grounding. The code requires a #6 copper minimum ground wire from the panel neutral bus to the first ground rod and then continuing to the second ground rod at least 6 feet away. In post #1 you reference 2 ground bars. IF you have a separate ground bar it would be separate from the neutral. You terminate the GEC to the neutral bus and not the ground bar. The grounded neutral bus is bonded to the panel box by either a strap or green bonding screw.
 
  #18  
Old 03-20-15, 08:46 AM
I
Forum Topic Moderator
Join Date: Feb 2005
Location: Near Lansing, Michigan
Posts: 10,941
Received 45 Votes on 43 Posts
Mnords, do you know which NEC revision your city / area is following? This can make a big difference in terms of what wiring methods are allowed relative to the spa and the panel(s).

There are flexible wiring methods which have insulated grounds, but they are not all that common in the US. For example a common one for hot tubs and spas in Canada is called Teck cable which is very similar to the PVC jacketed cable CasualJoe mentioned above. It can be used in the US, but in my experience it will be a special order item. There are some grades of MC cable which meet the grounding need and could also be buried, but not all MC will meet this requirement, so again maybe a special order.

Where exactly is the tub relative to the detached garage? Can you post a picture or sketch of the site with the main players (buildings, panels, tub) identified?
 
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: