Hot tub

[bradleymattlin]

Have a question about article 680 on outdoor hot tubs. I have a hot tub self contained recessed on a porch about 10 feet off the ground. So you actually step down into the tub. Nothing conductive around the tub so why should the perimeter have to be bonded.

 

[Dennis Alwon]

The main reason IMO is the code requires it and has no exceptions because of the deck height. If there are stray voltages in the area then the equipotential bonding is suppose to protect the user from potential shock. Is it probably up that high to have stray voltage. I don't think so but I don't know for certain.

 

[A/A Fuel GTX]

How are you supposed to bond the perimter of a hot tub on a wooden or a composite deck?

 

[Gregg Harris]

Have a question about article 680 on outdoor hot tubs. I have a hot tub self contained recessed on a porch about 10 feet off the ground. So you actually step down into the tub. Nothing conductive around the tub so why should the perimeter have to be bonded.

Which section 680 are you questioning?

 

[kwired]

How are you supposed to bond the perimter of a hot tub on a wooden or a composite deck?

Attach a lug to the wood and land your conductor in it. Make sure the fastening means has at least two threads engaged into the wood. If pressure treated lumber make sure to use suitable lug and attachment hardware for withstanding the treatment chemicals:happyyes:

 

[Dennis Alwon]

680.26 requires the equipotential bonding to be in the earth around the perimeter of the tub 18-24" from the inside wall and 4-6" deep. There are no exceptions unless you meet the tia and your state approved it, which in ths op's case it does not come into play

 

[kwired]

680.26 requires the equipotential bonding to be in the earth around the perimeter of the tub 18-24" from the inside wall and 4-6" deep. There are no exceptions unless you meet the tia and your state approved it, which in ths op's case it does not come into play

sounds to me like the area 18-24 inches below the tub and 4-6 inches below is just free air space.

Does the NEC expect the floor around such an installation to be a conductive surface? True you may get some conductivity out of wet treated lumber, but just how do you effectively bond to it?

 

[Dennis Alwon]

sounds to me like the area 18-24 inches below the tub and 4-6 inches below is just free air space.

Does the NEC expect the floor around such an installation to be a conductive surface? True you may get some conductivity out of wet treated lumber, but just how do you effectively bond to it?

18-24 inches from the inside wall of the pool- we are talking a perimeter bonding in the earth

 

[kwired]

18-24 inches from the inside wall of the pool- we are talking a perimeter bonding in the earth

The OP has a hot tub (flush/semi flush) in a deck 10 feet above grade. I was saying this area in relation to his hot tub is not in the earth but rather 7-8 feet above grade and there is nothing there except free air and maybe an occasional support member for the deck.

 

[Dennis Alwon]

The OP has a hot tub (flush/semi flush) in a deck 10 feet above grade. I was saying this area in relation to his hot tub is not in the earth but rather 7-8 feet above grade and there is nothing there except free air and maybe an occasional support member for the deck.

Okay but the code still gives no exception. The posts that connect to the deck , when wet, can still carry stray voltages.

 

[kwired]

Okay but the code still gives no exception. The posts that connect to the deck , when wet, can still carry stray voltages.

Which brings us back to how do you effectively bond them?

 

[Gregg Harris]

I do not believe the perimeter surface which is the elevated deck is what is implied in
(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 surfaces and other types of paving. Perimeter surfaces less than 1 m (3 ft) separated by a permanent wall or building 1.5 m (5 ft) in height or more shall require equipotential bonding on the pool side of the permanent wall or building. 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.

If the hot tub was setting directly on the ground, asphalt or concrete then the 3 foot perimeter would come into play.

 

[kwired]

I do not believe the perimeter surface which is the elevated deck is what is implied in
(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 surfaces and other types of paving. Perimeter surfaces less than 1 m (3 ft) separated by a permanent wall or building 1.5 m (5 ft) in height or more shall require equipotential bonding on the pool side of the permanent wall or building. 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.

If the hot tub was setting directly on the ground, asphalt or concrete then the 3 foot perimeter would come into play.

Problem is it does not say "grounded" surfaces, it just says "perimeter" surface

There is relief in TIA 11-1:

1. Revise 680.42(B) to read as follows:

680.42(B) Bonding. Bonding by metal-to-metal mounting on a common frame or base shall be permitted.

Exception No. 1: The metal bands or hoops used to secure wooden staves shall not be required to be bonded as required in 680.26.

Exception No. 2: A listed self-contained spa or hot tub that meets all of the following conditions shall not be required to have equipotential bonding of perimeter surfaces installed as required in 680.26(B)(2):

(1) Is installed in accordance with manufacturer?s instructions on or above grade.

(2) The vertical measurement from all permanent perimeter surfaces within 30 horizontal inches (76 cm) of the spa to the top rim of the spa is greater than 28 inches (71 cm).

Informational Note: For further information regarding the grounding and bonding requirements for self-contained spas and hot tubs, see ANSI/UL 1563 ? 2009,Standard for Electric Spas, Equipment Assemblies, and Associated Equipment.

Issue Date: March 1, 2011

Effective Date: March 21, 2011

Problem is the OP's install is flush/semi flush in the floor of the deck which doesn't meet exception 2 condition 2. If his spa were freestanding on the deck then the TIA would likely be applicable.

 

[shortcircuit2]

Attach a lug to the wood and land your conductor in it. Make sure the fastening means has at least two threads engaged into the wood. If pressure treated lumber make sure to use suitable lug and attachment hardware for withstanding the treatment chemicals:happyyes:

LMFAO!!!

 

[Dennis Alwon]

Which brings us back to how do you effectively bond them?

Just as you would if the deck were on the ground. I have done that and then also run the bond under the deck boards around the tub.

I can only say that this is the interpretation that was given to us at the NC state meeting by a cmp member. I know many areas that think it is unnecessary and don't require it.

 

[kwired]

Just as you would if the deck were on the ground. I have done that and then also run the bond under the deck boards around the tub.

I can only say that this is the interpretation that was given to us at the NC state meeting by a cmp member. I know many areas that think it is unnecessary and don't require it.

Sounds about as effective as what I mentioned in post #5. Don't forget to put bonding bushings on PVC adapters if you used any.

 

[Dennis Alwon]

Sounds about as effective as what I mentioned in post #5. Don't forget to put bonding bushings on PVC adapters if you used any.

I never said it was effective but that it was an interpretation by some. I figured if I did as stated in the code then I am covered.

 

[augie47]

If adopted or considered, remember there is a TIA on hot tubs:


Reference: 680.42(B)
TIA 11-1
(SC 11-3-10/TIA Log #1005)
Pursuant to Section 5 of the NFPA Regulations Governing Committee Projects, the National Fire Protection Association has issued
the following Tentative Interim Amendment to NFPA 70?, National Electrical Code?, 2011 edition. The TIA was processed by Panel
17 and the National Electrical Code Technical Correlating Committee, and was issued by the Standards Council on March 1, 2011,
with an effective date of March 21, 2011.
A Tentative Interim Amendment is tentative because it has not been processed through the entire standards-making procedures. It is
interim because it is effective only between editions of the standard. A TIA automatically becomes a proposal of the proponent for the
next edition of the standard; as such, it then is subject to all of the procedures of the standards-making process.
1. Revise 680.42(B) to read as follows:
680.42(B) Bonding. Bonding by metal-to-metal mounting on a common frame or base shall be permitted.
Exception No. 1: The metal bands or hoops used to secure wooden staves shall not be required to be bonded as required in 680.26.
Exception No. 2: A listed self-contained spa or hot tub that meets all of the following conditions shall not be required to have
equipotential bonding of perimeter surfaces installed as required in 680.26(B)(2):
(1) Is installed in accordance with manufacturer?s instructions on or above grade.
(2) The vertical measurement from all permanent perimeter surfaces within 30 horizontal inches (76 cm) of the spa to the top
rim of the spa is greater than 28 inches (71 cm).
Informational Note: For further information regarding the grounding and bonding requirements for self-contained spas and hot
tubs, see ANSI/UL 1563 ? 2009, Standard for Electric Spas, Equipment Assemblies, and Associated Equipment.
Issue Date: March 1, 2011
Effective Date: March 21, 2011
(Note: For further information on NFPA Codes and Standards, please see www.nfpa.org/codelist)

 

[Gregg Harris]

This has got to be one of the biggest FUBAR created. If you go through all of the ROP,ROC,TIA on this subject loads of information on bonding grids not being needed for hot tubs mounted on decks has been proposed and accepted by CMP 17 but no one has submitted clear language to enter into 680.42(B). For some reason the height requirement of 28 inches with a horizontal distance of 30 inches of perimeter surfaces keeps getting inserted as an exception to exempt the bonding grid. The latest verbiage does state that the vertical distance from non conductive steps used to enter the tub should not be used. Attempting to bond a non-conductive deck to a grid is ridicules.

 

[bradleymattlin]

How would stray voltage get to the deck when wood is non conductive. That means any wood deck could get stray voltage with or without a hot tub.