Hot tub grounding and bonding

[Mustang125]

Hello I just installed a hot tub on a existing concrete slab, the inspector came and said that there needs to be a #8 bare wire buried 18" away and all the way around the tub. I can't find this in the code, any help? He said I would have to saw cut around the whole tub and lay it in there.

 

[Dennis Alwon]

If you area accepted the TIA which is now part of the 2014 NEC then the inspector is correct if you meet the requirements

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).

 

[Jljohnson]

The exception in what Dennis copied and pasted gets you out of doing this if it a "listed self contained" spa, which most residential hot tubs are.

 

[Mustang125]

If you are accepted the TIA which is now part of the 2014 NEC then the inspector is correct if you meet the requirements

what does the last part of this mean exactly, the vertical surfaces? if there is something shorter than 28" then it does need a ring?

 

[edlee]

If you are accepted the TIA which is now part of the 2014 NEC then the inspector is correct if you meet the requirements

Hey Dennis, maybe it's because it's Friday after work, but I cannot understand this sentence. It sounds to me that "if you meet the requirements (of the TIA)" then the inspector is wrong.

Would you please clarify it for me?

Thanks........Lee

 

[edlee]

what does the last part of this mean exactly, the vertical surfaces? if there is something shorter than 28" then it does need a ring?

I take that to mean that if there is any horizontal surface less than 28" vertically from the top of the tub, like a rock wall on one side, or who knows what, then yeah you need the ring.

BTW doesn't New Hampshire use the NEC? It's in the pool section of 680, Part II.

 

[kwired]

what does the last part of this mean exactly, the vertical surfaces? if there is something shorter than 28" then it does need a ring?

Most of these packaged units will be higher then 28". If you set them on a typical slab, you shouldn't have much to worry about. Should you set the thing into a hole, say to make the rim flush/near flush with the surrounding surfaces, you will need to think harder about this 28" rule. I guess if you have a short wall or even a railing nearby you need to think about that as well, if it is less then 30" away.

Setting in a hole would not comply with condition 1 if the hole is below grade, but it may be common to set the spa on a slab or even on grade, and build a deck around it making it flush/nearly flush with the deck. But that gets us back to an earlier issue many had before the TIA came out of how to bond a non conductive deck

 

[Dennis Alwon]

what does the last part of this mean exactly, the vertical surfaces? if there is something shorter than 28" then it does need a ring?

That is correct. If you measure from the base of the tub outward 30" and maintain a height greater than 28" from the floor level to the top of the top then you are good to go- no equipotential bonding is needed.

As Kwired mentioned. Sink the tub into a deck and you may have less then 28" then the bonding is necessary. I guess they want you in the tub and not touching the ground at the same time to avoid shock.

 

[MasterTheNEC]

Hey Dennis, maybe it's because it's Friday after work, but I cannot understand this sentence. It sounds to me that "if you meet the requirements (of the TIA)" then the inspector is wrong.

Would you please clarify it for me?

Thanks........Lee

Umm..I was going to ask the same thing as it's now Monday and my coffee has not kicked in.

I think what Dennis is saying is that IF the local AHJ has not accepted the TIA then he would be correct. The TIA gives him an out if he meets all the provisions expressed in the TIA and then and only then if the local AHJ accepts the TIA unless his local jurisdiction has adopted the 2014 NEC to which 680.42(B) gives him an out, if applicable.

Maybe Dennis is posting at 1:45AM again...lol

 

[MasterTheNEC]

If you AHJ accepted the TIA which is now part of the 2014 NEC then the inspector is wrong if you meet the requirements

Here I fixed it for the Old Man Moderator...lol

 

[Dennis Alwon]

Maybe it is the coffee or maybe the steroids who knows. But it should have said "If your area did not accept the Tia then the inspector is correct-- that was what I was thinking anyway. In other words, no perimeter bond is necessary if the TIA is in effect. If not then the perimeter bond is necessary.

 

[david]

Maybe it is the coffee or maybe the steroids who knows. But it should have said "If your area did not accept the Tia then the inspector is correct-- that was what I was thinking anyway. In other words, no perimeter bond is necessary if the TIA is in effect. If not then the perimeter bond is necessary.

I?m not sure how this exception helps when people walk up to the tub and the husband and wife talk holding hands or leaning into each other.

Either the bonding is needed or it is not.

To think that 28 inch elevation his going to keep persons isolated from ground contact doesn?t make any sense.

 

[Dennis Alwon]

I?m not sure how this exception helps when people walk up to the tub and the husband and wife talk holding hands or leaning into each other.

Either the bonding is needed or it is not.

To think that 28 inch elevation his going to keep persons isolated from ground contact doesn?t make any sense.

I agree it is odd. Now suppose you have a set of stairs attached to the floor to step into the tub-- then what. I did not write the code and the code says it is not always needed.

 

[ActionDave]

I?m not sure how this exception helps when people walk up to the tub and the husband and wife talk holding hands or leaning into each other.

Either the bonding is needed or it is not.

To think that 28 inch elevation his going to keep persons isolated from ground contact doesn?t make any sense.

Well I think the preponderance of the evidence that there has been ZERO incidents of stray voltage problems with any of the thousands of above ground hot tubs in the United States, and quit possibly Canada, makes it reasonable to not require a bonding wire in the slab.

 

[david]

Well I think the preponderance of the evidence that there has been ZERO incidents of stray voltage problems with any of the thousands of above ground hot tubs in the United States, and quit possibly Canada, makes it reasonable to not require a bonding wire in the slab.

That may be correct, more directly to the point. If it is important than leave it alone if it is not needed remove the requirement. It gets hard enough to get the pool guys on board with the idea of stray voltages. We get them on board with the concept and here comes a change indicating it is only important sometimes, and some 28 in high wall is going to isolate the users from ground contact

When the changes do not make sense this gets tiresome

 

[shortcircuit2]

I?m not sure how this exception helps when people walk up to the tub and the husband and wife talk holding hands or leaning into each other.

I agree...and if she is holding their infant child...it could be catastrophic.

But there are no reported deaths...yet. Until then the rule has been removed to increase profits.

 

[kwired]

I agree...and if she is holding their infant child...it could be catastrophic.

But there are no reported deaths...yet. Until then the rule has been removed to increase profits.

Who is seeing increased profits?

Installers don't have to put in the extra equipment. Hot tub sales is probably not effected all that much, as most consumers will purchase the tub then are later surprised to find out how much it costs to connect it.