#8 bonding of whirlpool tubs

Status
Not open for further replies.

mjr10

Member
Hi-
Some time ago Mike Holt answered a question about running the #8 bond back to the service panel from a spa tub. I believe he said that it was not necessary - it was only for bonding all metal parts at the tub location. Can anyone out there verify this for me? I've got a meeting with an inspector tomorrow and I think it will possibly come up. Thanks!
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
Hi-
Some time ago Mike Holt answered a question about running the #8 bond back to the service panel from a spa tub. I believe he said that it was not necessary - it was only for bonding all metal parts at the tub location. Can anyone out there verify this for me? I've got a meeting with an inspector tomorrow and I think it will possibly come up. Thanks!
The #8 bond is only to keep the earth at an equal potential around the area of the tub. The bonding just connects all metal parts together with the equipotential bonding grid. It does not go back to the panel.
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
Here is a graphic from Mike

ry%3D480
 

mjr10

Member
For some reason, electricians in my neck of the woods have always run the #8 back to the panel. I never did, because I couldn't find evidence in the Code to support it. I remember reading Mike's response to this question in an old issue of EC&M magazine (maybe from last year?) and I was hoping to find it so I could show a copy of the Q&A to the inspector, since I can't quote a section of the Code that says not to do something! He's a Mike Holt fan, so I thought that might help my case as opposed to "you should do it because that's what everyone else does around here".
 

roger

Moderator
Staff member
Location
Fl
Occupation
Retired Electrician
The bonding is as already said, only for equipotential.

It wouldn't matter if all the bonded parts are at a potential difference of 2401 volts to some other surface as long as all touch potential is equal.

Take the #8 and bond the conductive parts together, when you get to last item drop the #8, your done, it is not an EGC.

Roger
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
Here is the 2011 Draft of the NEC. This should clarify the remote panelboard issue.



680.26 Equipotential Bonding.

(A) Performance.
The equipotential bonding required by this section shall be installed to reduce voltage gradients in the pool area.
(B) Bonded Parts.
The parts specified in 680.26(B)(1) through (B)(7) shall be bonded together using solid copper conductors, insulated covered, or bare, not smaller than 8

AWG or with rigid metal conduit of brass or other identified corrosion-resistant metal. Connections to bonded parts shall be made in accordance with 250.8. An 8 AWG or larger solid copper bonding conductor provided to reduce voltage gradients in the pool area shall not be required to be extended or attached to remote panelboards, service equipment, or electrodes.
 

shepelec

Senior Member
Location
Palmer, MA
It already states that it is not required to be run to panel boards, yet I see it all the time especially with the use of pecs tubing.:roll:
 

fireryan

Senior Member
Location
Minnesota
Is this whirlpool tub one that sits outside or is he talking about the small ones that sit in your bathroom? For the tubs that sit in your bathroom we just bond the hot and cold water pipe together with a #8 and then run to the whirlpool pump and bond there also
 

M. D.

Senior Member
Well I found this
http://ecmweb.com/nec/code-basics/pools-spas-3-20090601/
( for some reason I had to scroll way down the page to see it )

and here it is in question and answer format
http://ecmweb.com/nec/code_qa/electric_stumped_code_51/

(again I had to scroll way down the page which appears blank)

Q. What are the grounding and bonding requirements for a hydromassage bathtub?

A. If the building contains a metal piping system, it must be bonded with a solid copper equipotential bonding jumper, sized not smaller than 8 AWG, to the circulating pump (if it's not double insulated), and to any other grounded metal parts that contact the circulating water. The bonding is to be done at the location of the motor. This equipotential hydromassage bonding jumper is not required to be connected to any remote panelboard, service equipment, or electrode [680.74].
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
Is this whirlpool tub one that sits outside or is he talking about the small ones that sit in your bathroom? For the tubs that sit in your bathroom we just bond the hot and cold water pipe together with a #8 and then run to the whirlpool pump and bond there also

Good question. The difference being the hydromassage tub or a spa or hot tub. Assuming the op is using NEC wording then we are talking hot tub or spa which remains filled and chemicals are used to treat the water. A hydromassage is just a bathtub with jets, heaters, etc. and gets filled with every use.
 

sameguy

Senior Member
Location
New York
Occupation
Master Elec./JW retired
Back in the 80's it was code to run the ground back to the panel, I questioned this practice with "Inspector" stating what about the grnd. need not be larger than the feed; answer "thats what the book said to do so we have to have it." It was changed to todays code on the next revision,(no not due to me!).
 

cmreschke

Senior Member
have always bonded the indoor tubs to the closest cold water from motor (assuming conduit is copper) when it was plastic took my #8 back to panel so the motor was bonded to ground. am not quite sure the illustration is the same as that refers to a pool not a tub imo (unless there is a chance i am wrong dont have my book in front of me)
 

Split Bolt

Senior Member
Back in the '80s, we used to run the #8 solid all the way back to the panel because that's the way everybody else was doing it. When I realized that this was not necessary and didn't do it, I had a bookmark in my code book so I could argue with the inspector when he came for the rough-in inspection. Needless to say, there was no argument and I haven't done it since. I would like to have all of that wasted copper back right now. Someone told me they are giving close to $5 a pound!:grin:
 
Status
Not open for further replies.
Top