Exterior packaged hot tub

[grasfulls]

We have typically run a #8 equipment bond to hot tubs. In this situation we ran a 6/3 NMS cable (has a #10 bare ground) to a unit to be installed on a balcony off a residence. I have ordered the #8 and I was plannning on installing it when I read this:

2005 NEC section 680.42 subsection (C):
(C) Interior Wiring to Outdoor Installations In the interior of a one-family dwelling or in the interior of another building or structure associated with a one-family dwelling, any of the wiring methods recognized in Chapter 3 of this Code that contain a copper equipment grounding conductor that is insulated or enclosed within the outer sheath of the wiring method and not smaller than 12 AWG shall be permitted to be used for the connection to motor, heating, and control loads that are part of a self-contained spa or hot tub or a packaged spa or hot tub equipment assembly.

Does this mean I may just use the #10?

[ August 05, 2005, 08:33 PM: Message edited by: grasfulls ]

 

[websparky]

Re: Exterior packaged hot tub

Are you confusing "bonding" with "equipment grounding"??

 

[grasfulls]

Re: Exterior packaged hot tub

*sigh* probably, but I do not see what there is to bond, whereas the equipment must be grounded, yes? If you can clarify, it will help.

[ August 05, 2005, 08:35 PM: Message edited by: grasfulls ]

 

[bphgravity]

Re: Exterior packaged hot tub

Equipment and devices need an effective fault path to carry fault current back to the source. This is accomplished by the equipment grounding conductor. In some cases, such as pools and hot tubs, equipotential bonding is required to reduce the possibility of touch and step potential voltage by intentionally connecting all conductive parts together. This bonding does not serve to remove fault currents.

 

[grasfulls]

Re: Exterior packaged hot tub

Thanks bphgravity.

I believe this bonding is done to potential current carrying metal parts such as rebar, but would not include those items connected to an equipment ground. Why connect a small equipment ground to something that already has a large bonding jumper connected to it? The bonding makes all metal parts a compnent of a grid, hopefully eliminating any potential, whereas the equipment ground is for those metal parts that may need to carry a short circuit, like a motor, is this correct?

So, if there appear to be no metal parts needing bonding, I believe all I need is the equipment ground and the code appears to say I may now use a #12 equipment ground.

If I still need a bond, what components should be bonded?

 

[jwelectric]

Re: Exterior packaged hot tub

Good explanation Mr. Holland but I have a question about where this tub is going to sit, on a balcony off a residence.

Should this be a concrete balcony then 680.26 (C) would need some attention as outlined in 680.42.

 

[grasfulls]

Re: Exterior packaged hot tub

Wooden balcony to be hot mopped and tiled, no steel anywhere in sight, well, at least not within 5 feet. Although there will be a metal cover and junction box next to it when all is said and done. It would be a drag to have to bond those, I think they should only require an equipment ground since the conductors pass through it.

BTW, the balcony is off of the second floor. So, what do you think about the #12 equipment ground and no bond?

[ August 05, 2005, 09:16 PM: Message edited by: grasfulls ]

 

[jwelectric]

Re: Exterior packaged hot tub

What is hot mopped and tiled?

Is this like a ceramic tile?

The NEC states that nothing smaller than a #12 equipment grounding conductor. This hot tub is outside therefore it must comply to part II of 680 (II. Permanently Installed Pools)
680.21 says, ? Any wiring method employed shall contain an insulated copper equipment grounding conductor sized in accordance with 250.122 but not smaller than 12 AWG.?
Watch for the manufacture to ask for a larger equipment grounding conductor,

 

[JES2727]

Re: Exterior packaged hot tub

grasfulls,
I believe the code section you referenced allows you to use the #12.

John

 

[grasfulls]

Re: Exterior packaged hot tub

The "balcony" is actually a deck I suppose, sorry. It is over a room. Hot moppeed is the same as what they do for a flat roof, tar paper, hot tar, tar paper, hot tar,( I do not know how many layers), I think I would prefer the same membrane as a shower gets today.... I suppose the tile will be ceramic. We could not bring the conductors up into the unit because they want NO penetrations through the finished "floor" or deck, or whatever it is. Therefore, we went through what will be a stuccoed low height wall.

I get away from the main point. I am going to leave the bond out and just stay with an equipment ground and see what the inspector says.

[ August 05, 2005, 10:02 PM: Message edited by: grasfulls ]

 

[jwelectric]

Re: Exterior packaged hot tub

If the finish floor is ceramic tile then you will need to install an equipotential bonding grid as outlined in 680.26 (C)(3). This grid will bond to the pump motor with a #8.

 

[grasfulls]

Re: Exterior packaged hot tub

Wow,
How would a grid be placed if it is just a thinset to hold the tile down? What would the grid be comprised of? Rebar and I assume screen is supposed to have a minimum of 2" of concrete to either side. What would happen if someone had an existing deck and they set a hot tub on it?

I see in the handbook that epoxy coated rebar needs no bond at all, so how is a grid comprised then?
Thank you,
Gary

 

[grasfulls]

Re: Exterior packaged hot tub

Hi JW,

It is not a permanently installed swimming pool (hot tub or spa also, I hope) and I believe the concrete is mentioned here due to its contact with the earth, so I am not sure it applies here...phew

I read this:
Creating an electrically safe environment in and around permanently installed swimming pools requires the installation of a bonding system with the sole function of establishing equal electrical potential (voltage) in the vicinity of the swimming pool. A person who is immersed in a pool or who is dripping wet, has a large amount of exposed skin, and is lying or walking on a concrete deck is extremely susceptible to any differences in electrical potential that may be present in the pool area.

[ August 05, 2005, 10:38 PM: Message edited by: grasfulls ]

 

[jwelectric]

Re: Exterior packaged hot tub

To answer the question of the grid, this is outlined in 680.25 (C)(3) as;

a. Materials and Connections. The grid shall be constructed of minimum 8 AWG bare solid copper conductors. Conductors shall be bonded to each other at all points of crossing. Connections shall be made as required by 680.26(D).
b. Grid Structure. The equipotential bonding grid shall cover the contour of the pool and the pool deck extending 1 m (3 ft) horizontally from the inside walls of the pool. The equipotential bonding grid shall be arranged in a 300 mm (12 in.) by 300 mm (12 in.) network of conductors in a uniformly spaced perpendicular grid pattern with tolerance of 100 mm (4 in.).
c. Securing. The below-grade grid shall be secured within or under the pool and deck media.

But this is held down with thin set. Well read this, table 110.26 (A)(1) Condition 2 ? Exposed live parts on one side of the working space and grounded parts on the other side of the working space. Concrete, brick, or tile walls shall be considered as grounded.


What if it was installed on an existing concrete pad, here is what is I was told in my state;
Mike, 680.26(C) would apply to a new installation of a hot tub outdoors. The paved walking deck 3' out from the tub would need the equipotential bonding grid to be installed per the NEC. On existing paved areas where a hot tub is installed, this is a new installation of the tub, so the equipotential bonding grid would have to be installed or a non paved walking surface could be installed then 680.26(C) would not apply.
I hope this will clarify any questions that you may have.
Pay real close attention starting with the words ?this is a new installation of the tub so?

As far as this being a hot tub look as this:
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 680.42(B), that would otherwise apply to pools installed outdoors.

Part 2 is II. Permanently Installed Pools, yes this tub is a II. Permanently Installed Pool.

 

[websparky]

Re: Exterior packaged hot tub

Gary,

Please read all of "680.26 Bonding" as this does apply to your installation.

Proper bonding is very important!

 

[grasfulls]

Re: Exterior packaged hot tub

Thanks everyone, I shall read it in its entirety before posting anything else.

Gary

 

[grasfulls]

Re: Exterior packaged hot tub

ok,
i am thoroughly reading it all. I have checked the 2002 and 2005 code book and cannot find this:
To answer the question of the grid, this is outlined in 680.25 (C)(3) as;

JW, could you please tell me what year code book this is. The prints are stamped for 2002, so I need to stop reading the 2005, this also means I need to leave earlier versions out.

Thanks,
Gary

 

[infinity]

Re: Exterior packaged hot tub

This is new for the 2005 NEC. Take a look at this link, scroll down for more photo's.

http://electrical-contractor.net/ubb/Forum2/HTML/002086.html

[ August 06, 2005, 07:11 PM: Message edited by: infinity ]

 

[grasfulls]

Re: Exterior packaged hot tub

Hi Infinity,
The 2005 has a lot of info I cannot find elswhere, thanks for including the photo.
Gary

All:
I have endeavored to read everything and got pretty turned around. I am now sticking with the 2002 code because the prints are stamped as such. relative to JW's post (a good one, thanks!)

But this is held down with thin set. Well read this, table 110.26 (A)(1) Condition 2 ? Exposed live parts on one side of the working space and grounded parts on the other side of the working space. Concrete, brick, or tile walls shall be considered as grounded.

I suppose that the argument could be that the code states walls, not floors. However, I believe the intent of the definition for clearances is for those materials installed in such a way that a clear path to ground may be established. I would have to ask, does one tile placed on insulated material, said tile having no contact with ground, now make a ground? If someone spills concrete on carpet in front of a receptacle, is the clearance now non-code compliant? I am unsure that a ceramic floor on a 2nd story balcony constitues a potential ground path. Also, if a person kills the power before working on it, there are no exposed live parts to deal with.

After reading everything, I believe the second story constitutes an area with no path to ground. one of the grid references within this thread is:

c. Securing. The below-grade grid shall be secured within or under the pool and deck media.

and there is no way a below grade grid is going to do anything here, grade is 12 feet down, unless the floor of the deck is somehow going to be construed as grade. I believe they want a true below grade install for its contact with the earth.

680.26(C) would apply to a new installation of a hot tub outdoors. The paved walking deck 3' out from the tub would need the equipotential bonding grid to be installed per the NEC. On existing paved areas where a hot tub is installed, this is a new installation of the tub, so the equipotential bonding grid would have to be installed or a non paved walking surface could be installed then 680.26(C) would not apply.

I agree that a paved surface touching the ground may create a potential, I honestly do not see it up on the second floor. Perhaps if there were structural steel bonded to the overall grounding grid, and the thin set and tile came into contact with the steel, I would argue the need for a grid (or at least state my belief of a need for a grid and let the GC decide - I don't know, it would be quite an expense to add a grid to this and I do not see where it will do anything).

I must contend that the only metal parts within 5 feet of the tub will be a 4-11/16 blank cover which I will ground with the #10 encased withiin the 6/3 NM cable and leave it as an equipment ground. There are no metal parts such as ladders or other non conductor related parts that could conceivably require a #8 bond to a grid to relieve a potential curent path of possible conductive parts.

I sure hope I am making the right decision, I want the installation to not only be code compliant, but safe. I truly appreciate all of your efforts and inpt. I also welcome any differing perspective, especially if it makes sense and helps me see the need to implement it.


Gary

[ August 06, 2005, 07:51 PM: Message edited by: grasfulls ]

 

[ronaldrc]

Re: Exterior packaged hot tub

I thought you said a hot Tub. The ones I am use to hooking are fiberglass foam and wood what are you going to have a special ground for?


If its straight 230 volts you need 6/2 w/ grd.
If its 230/120 you 6/3 w/ grd.

And a disc. at least 5 ft. from the unit and within sight.And I should have mentioned GFI protection usually at the panel.

Thats the way we do it here.

Ronald

[ August 06, 2005, 08:46 PM: Message edited by: ronaldrc ]