Do you need a bonding grid around a hot tub?

Status
Not open for further replies.

zappy

Senior Member
Location
CA.
It would be sitting on either dirt, or concrete. I don't think you do, but I better make sure. Thank you.
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
It would be sitting on either dirt, or concrete. I don't think you do, but I better make sure. Thank you.
I believe you do

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 is where the epb comes into play. This is the 2008 NEC
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
The way I read it it's any surface:

680.26 Equipotential Bonding.
(2) Perimeter Surfaces. The perimeter surface shall extend for 1 m (3 ft) horizontally beyond the inside walls of the pool and shall include unpaved surfaces as well as poured concrete and other types of paving. Bonding to perimeter surfaces shall be provided as specified in 680.26(B)(2)(a) or (2)(b) and shall be attached to the pool reinforcing steel or copper conductor grid at a minimum of four (4) points uniformly spaced around the perimeter of the pool. For nonconductive pool shells, bonding at four points shall not be required.
(a) Structural Reinforcing Steel. Structural reinforcing steel shall be bonded in accordance with 680.26(B)(1)(a).
(b) Alternate Means. Where structural reinforcing steel is not available or is encapsulated in a nonconductive compound, a copper conductor(s) shall be utilized where the following requirements are met:
(1) At least one minimum 8 AWG bare solid copper conductor shall be provided.
(2) The conductors shall follow the contour of the perimeter surface.
(3) Only listed splices shall be permitted.
(4) The required conductor shall be 450 to 600 mm (18 to 24 in.) from the inside walls of the pool.
(5) The required conductor shall be secured within or under the perimeter surface 100 mm to 150 mm (4 in. to 6 in.) below the subgrade.
 

goldstar

Senior Member
Location
New Jersey
Occupation
Electrical Contractor
infinity said:
The way I read it it's any surface:
You're correct except if it's a wooden deck or platform.
zappy said:
I believe were still in 05 in northern calif. I'll have to call the building dept. and see what they say.
Hopefully you'll be able to file under the 2008 code where you can just wrap a length of # 8 solid around the outside walkway area of tub. If not, you'll have to install the rather expensive bonding grid. If it's on a concrete slab with re-bar or mesh inside you should be able to use the re-bar or mesh as the EPB. Check with your local inspector.
 

goldstar

Senior Member
Location
New Jersey
Occupation
Electrical Contractor
Where is the exclusion for those?
Wood is not considered a conductive material. Perhaps it's just a New Jersey thing. Our Division of Codes and Standards of the DCA makes interpretations of the NEC and sometimes makes small modifications based on common sense. For example, in the 2005 code we did not accept the use of arc fault breakers because test reports on various mfr's products showed numerous faults and problems with their breakers. We've since adopted the 2008 Code in its entirety.

Anyway, if you're bidding against me here in NJ on a hot tub install (under the 2005 code) with wood decking on the ground, if you're planning to install a bonding grid under the deck, unless my price is way out of whack - I'll get the job every time.
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
Wood is not considered a conductive material. Perhaps it's just a New Jersey thing. Our Division of Codes and Standards of the DCA makes interpretations of the NEC and sometimes makes small modifications based on common sense. For example, in the 2005 code we did not accept the use of arc fault breakers because test reports on various mfr's products showed numerous faults and problems with their breakers. We've since adopted the 2008 Code in its entirety.

Anyway, if you're bidding against me here in NJ on a hot tub install (under the 2005 code) with wood decking on the ground, if you're planning to install a bonding grid under the deck, unless my price is way out of whack - I'll get the job every time.
I would be willing to bet that wet wood, especially wet wood on the ground, is conductive enough to carry enough current to kill you. The "common sense" answer would be to prohibit surfaces that cannot be bonded.
 

goldstar

Senior Member
Location
New Jersey
Occupation
Electrical Contractor
I would be willing to bet that wet wood, especially wet wood on the ground, is conductive enough to carry enough current to kill you.
Don, I suppose you're right but where do you draw the line on installing the bonding grid ? If the wood decking comes in contact with soil - should you install the grid ? If the wood decking is elevated and up on posts that are on concrete footings with re-bar in them - should you install the grid ? If so, should you be stapling the grid under the decking between the joists ? The decking is still getting wet and in your scenario is considered conductive.
The "common sense" answer would be to prohibit surfaces that cannot be bonded.
That's a good suggestion but one that I don't think will ever get a strong following. If the CMP's start getting too bizzare in their bonding grid designs we're going to start seeing paver blocks made with # 8 bonding wire hanging out of them.:grin:
 

John Valdes

Senior Member
Location
SC.
Occupation
Retired Electrician
Well, whats the answer? Do you have to use the grid for elevated tubs on decks. I was sure you did not have too? Yes or No?
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
For example, in the 2005 code we did not accept the use of arc fault breakers because test reports on various mfr's products showed numerous faults and problems with their breakers. We've since adopted the 2008 Code in its entirety.



Actually NJ has a few exceptions in the 2008 NEC adoption.
 
Status
Not open for further replies.
Top