# Grounding a Hot Tub Motor



## DMILL (Oct 26, 2010)

Hey guys, I have a question about grounding a hot tub, heres some info.

We are roughing in a house with a garage 200A service. The owner is installing 2 hot tubs. They say you have to have a seperate ground for the motor casing...

My question is, do I have to run that ground all the way back to the main panel where the motor is fed from (150' Away), or can I ground it to the main water line? (30' Away).

What does the current NEC Code say? Can you please include Article #'s.

Thank you!


----------



## theloop82 (Aug 18, 2011)

You would run the extra ground back to the ground bus on the panel you are originating the circuit out of. In fact I beleive it would be illegal to derive a separate ground just for a single circuit due to the chance of a difference of potential on your grounds.


----------



## therain (Jan 18, 2013)

If you talking about bonding the motor look at 680.74 (2011 NEC®


----------



## chicken steve (Mar 22, 2011)

In a nutshell, the theory is gfci's work best with better grounding, ergo the more #8 solid you can fan out of that G-bar on the side of the H-tub control panel , the more safety is enhanced .....~CS~


----------



## Dennis Alwon (May 9, 2009)

DMILL said:


> Hey guys, I have a question about grounding a hot tub, heres some info.
> 
> We are roughing in a house with a garage 200A service. The owner is installing 2 hot tubs. They say you have to have a seperate ground for the motor casing...
> 
> ...




You do not need to run the bond wire back to the panel. Nowhere in art 680 is that required-- not even for a pool. If there is a metal piping system in the house for the water then tie the motor bond to the water pipe.


----------



## jza (Oct 31, 2009)

chicken steve said:


> In a nutshell, the theory is gfci's work best with better grounding, ergo the more #8 solid you can fan out of that G-bar on the side of the H-tub control panel , the more safety is enhanced .....~CS~


Not saying you're wrong, but how can this be when a GFCI has very little to do with grounding?


----------



## chicken steve (Mar 22, 2011)

What Denny said....:thumbsup:

for some reason there's many of us that are led to believe we're safer if we tie an ECG around our big toe , and connect it to a serving Xfomer

our trades adage _"all grounding is not bonding, and all bonding is not grounding"_ is probably the most misunderstood of all electrical concepts, evident in it's hashing out in 250 to the _nth_ degree....



~CS~


----------



## chicken steve (Mar 22, 2011)

jza said:


> Not saying you're wrong, but how can this be when a GFCI has very little to do with grounding?


Good Q

One can hold onto the load _noodle_ in one hand, and the load _hot_ in the other and do the chicken dance all day long Jza

Up until (you guess please) happens

~CS~


----------



## jza (Oct 31, 2009)

chicken steve said:


> Good Q
> 
> One can hold onto the load _noodle_ in one hand, and the load _hot_ in the other and do the chicken dance all day long Jza
> 
> ...


Still don't understand. Are you saying you could be standing in the hot tub holding the line and neutral, receiving a shock, and that a properly grounded tub would prevent this?


----------



## Pete m. (Nov 19, 2011)

jza said:


> Still don't understand. Are you saying you could be standing in the hot tub holding the line and neutral, receiving a shock, and that a properly grounded tub would prevent this?


What I think CS is saying is that as long as the current going out on the ungrounded conductor matches the current returning on the grounded conductor is within 4 to 6 mA the GFCI will continue to deliver current until some of that current finds a separate path to cause an imbalance. 

That "other" path is usually a grounded surface.

Pete


----------



## chicken steve (Mar 22, 2011)

jza said:


> Still don't understand. Are you saying you could be standing in the hot tub holding the line and neutral, receiving a shock, and that a properly grounded tub would prevent this?


Rather the reverse Jza, the better bonded said tub is back to the serving GFCI, the better it will function

Perhaps a 'toon would clear it up?








~CS~


----------



## chicken steve (Mar 22, 2011)

Pete m. said:


> What I think CS is saying is that as long as the current going out on the ungrounded conductor matches the current returning on the grounded conductor is within 4 to 6 mA the GFCI will continue to deliver current until some of that current finds a separate path to cause an imbalance.
> 
> That "other" path is usually a grounded surface.
> 
> Pete


Thank you Pete....:thumbsup:
~CS~


----------



## Service Call (Jul 9, 2011)

The OP hasn't responded. Are we talking ground or bond?


----------



## electricmanscott (Feb 11, 2010)

Service Call said:


> The OP hasn't responded. Are we talking ground or bond?


Add to that hot tub or hydromasssage/whirlpool/ jacuzzi tub


----------



## DMILL (Oct 26, 2010)

The motor bond, sorry guys.


----------



## Service Call (Jul 9, 2011)

A bond is not a ground. It does "not" need to go to a panel or a water line. Unless you want to bond that water line.


----------



## electricmanscott (Feb 11, 2010)

Service Call said:


> A bond is not a ground. It does need to go to a panel or a water line. Unless you want to bond that water line.


Does NOT need to go to a panel.


----------



## chicken steve (Mar 22, 2011)

therain said:


> If you talking about bonding the motor look at 680.74 (2011 NEC®


Pretty much details the bonding of any proximal metallics and/or earth as 680.26,43 &42 do, with a _shall not _to the ocpd(s) Gbar



~CS~


----------



## chicken steve (Mar 22, 2011)

electricmanscott said:


> Does NOT need to go to a panel.


shall not ....

Making a GEC to the h20 line, as well as another #8 bond to a tub h20 line is asking for trouble....

~CS~


----------



## Dennis Alwon (May 9, 2009)

Service Call said:


> A bond is not a ground. It does need to go to a panel or a water line. Unless you want to bond that water line.


The bond for the tub is to keep the water the same potential as the tub. Now I was thinking this was a hydromassage tub where there is water connected to it. If it is a hot tub then you need an equipotential bond unless your area hs adopted the TIA for hot tubs.


----------



## Service Call (Jul 9, 2011)

electricmanscott said:


> Does NOT need to go to a panel.


 That's what I said

Edit. Sorry I just now noticed I didn't put "not" in the sentence b


----------



## chicken steve (Mar 22, 2011)

DMILL said:


> They say you have to have a seperate ground for the motor casing...


I am finding nothing in 680 that directs one to run this separate ground for the motor casing _(who's usual 680 ref is #8 solid cu bond)_ to a serving panel

~CS~


----------



## RIVETER (Sep 26, 2009)

DMILL said:


> Hey guys, I have a question about grounding a hot tub, heres some info.
> 
> We are roughing in a house with a garage 200A service. The owner is installing 2 hot tubs. They say you have to have a seperate ground for the motor casing...
> 
> ...


Why is the owner telling you what you have to do?


----------



## DMILL (Oct 26, 2010)

RIVETER said:


> Why is the owner telling you what you have to do?


The owner is not, the manufacturer of the tub(s) is.


----------



## chicken steve (Mar 22, 2011)

Anything _specific_ Derrick?


~CS~


----------



## DMILL (Oct 26, 2010)

chicken steve said:


> Anything specific Derrick?
> 
> ~CS~


We went ahead and took them to the copper water line.


----------



## RIVETER (Sep 26, 2009)

DMILL said:


> Hey guys, I have a question about grounding a hot tub, heres some info.
> 
> We are roughing in a house with a garage 200A service. The owner is installing 2 hot tubs. They say you have to have a seperate ground for the motor casing...
> 
> ...


There is a difference between Grounding and Bonding. Do you know that? Explain.


----------



## Speedy Petey (Jan 10, 2007)

DMILL said:


> We went ahead and took them to the copper water line.


I have to ask. Do even you own a code book?
This is from a week ago and you still don't seem 100% sure.


----------



## RIVETER (Sep 26, 2009)

Speedy Petey said:


> I have to ask. Do even you own a code book?
> This is from a week ago and you still don't seem 100% sure.


It seems to me that you are being a little:thumbsup: moderate.


----------



## DMILL (Oct 26, 2010)

Bonding- connecting all non current carrying structures (boxes, devices) together so there is a reliable path for fault current.

Grounding- creating a reliable path so fault current can flow back to thesource (ie) the neutral on the service. 

So in this case we technically bonded the motor casing to the earth (ie) the main water line... Correct?


----------



## DMILL (Oct 26, 2010)

Speedy Petey said:


> I have to ask. Do even you own a code book?
> This is from a week ago and you still don't seem 100% sure.


I was asked by my jman to see what I could find... No i do not own a current book, but I have an '05. He has one and checked... I was just curious as to what you all would say.. the inspector even seemed unsure. 

Were all here to learn, I never claimed to be a Jman. :thumbsup:


----------



## RIVETER (Sep 26, 2009)

DMILL said:


> Bonding- connecting all non current carrying structures (boxes, devices) together so there is a reliable path for fault current.
> 
> Grounding- creating a reliable path so fault current can flow back to thesource (ie) the neutral on the service.
> 
> So in this case we technically bonded the motor casing to the earth (ie) the main water line... Correct?


I can tell that you are confident. However, you are partially incorrect. Can you tell me why, before I tell you?


----------



## DMILL (Oct 26, 2010)

RIVETER said:


> I can tell that you are confident. However, you are partially incorrect. Can you tell me why, before I tell you?


No... I cannot...

Sorry if I came off as overly confident, that was not my intention.


----------



## chicken steve (Mar 22, 2011)

DMILL said:


> . the inspector even seemed unsure.


Part 4-spas and hot tubs (680.40) follows part 1 of 680

so read 680.26, and tell us what you think Derrick

~CS~


----------



## Dennis Alwon (May 9, 2009)

The idea behind a bond for the pump is to keep it at the same potential as everything else electrical around it. I am assuming this is a hydromassage tub since there is a water line involve so no equipotential bonding is necessary. However if the water pipe is metallic and bonded to the service then we want the motor and water lines to be the same potential. In most case we never bond the tubs motor as the water lines are not metallic.


----------



## chicken steve (Mar 22, 2011)

I might have a bit of a problem bonding to a metallic H2O that is _mutual _with the service GEC's ....

~CS~


----------



## Dennis Alwon (May 9, 2009)

chicken steve said:


> I might have a bit of a problem bonding to a metallic H2O that is _mutual _with the service GEC's ....
> 
> ~CS~


That is a nec rule. everything is at the same potential


----------



## chicken steve (Mar 22, 2011)

I'm not entirely sure the intent extends to 680 concerns Denny

I believe they look at the concept of bonding as _proximal isolation_ of said potential , _vs. _ many GEC's that become noodles .

It's all about the serving pool motor GFCI ......

680.74 , 3rd sentence states>

"The #8 or larger solid copper bonding shall be required for equpotential bonding in the area of the hydromassage bathtub and *shall not* be required to be extended or attached to any remote panelboard, service equipment, or _*electrode*._

680.25 (B)(2) insists feeders have insulated grounding conductors, even though the _'pool panel' _in a remote pool house should have a GEC, we wouldn't be required to run our motor bond to it

I once thought that, i'd run G-rods all around a pool from the pool panel, more grounding is better right? :thumbsup: 

I've had lots of help to rethink that .....

~CS~


----------



## Big John (May 23, 2010)

You could build a pool in the middle of the Mohave desert with no electrical service and you would still have to bond everything to establish an equipotential plane.

But you only need to worry about equipment grounding when there's electrical circuits involved.


----------



## Dennis Alwon (May 9, 2009)

Steve I am not saying that the #8 needs to go back to the panel. I am saying the pool pump ground lug may need a #8 between it and the copper water lines. That's it.... The first sentence in 680.74 states that


----------



## chicken steve (Mar 22, 2011)

Dennis Alwon said:


> Steve I am not saying that the #8 needs to go back to the panel. I am saying the pool pump ground lug may need a #8 between it and the copper water lines. That's it.... The first sentence in 680.74 states that


Oh? :001_huh:Well i guess my_ 'eyeglass denial_' excuse is all i can fall back on Denny

~CS~


----------



## wlweston (Jul 21, 2010)

*wlw*

The lug on the motor is for the equipotential bonding conductor. The conductor is a #8 bare solid conductor used to connect all metal parts together. It does not have to be grounded to anything. (see 680.26) If it is a self-contained system and listed as such, the equipotential bonding system is not required. (see 680.43 EX.2) Having said that, the motor still has to be grounded to the equipment grounding conductor. Requirements are different for hard-wired versus cord and plug assembly that comes with the hot tub. It's also a given that GFCI protection is required. You can find all the information you need in the NEC Article 680.


----------



## Service Call (Jul 9, 2011)

I just got a whirlpool bathtub and the instructions even state to run a separate #8 back to the panel. I'm not doing it. It even calls it an extra ground.


----------



## wlweston (Jul 21, 2010)

Years ago the theory was to run the equipotential bonding wire (#8 solid bare copper) to the panel. But studies since then have found that is not a desirable connection. Obviously some equipment suppliers don't know that the NEC changes every 3 years, and most time for the better. Keep safe!!


----------



## hotron (Aug 9, 2010)

*ground*

Hey! you may what to go up on the gauge of the wire..for example..if your using #12 awg up to #10 because of the distance.:thumbsup:and yes ground to main panel if there is no sub panel closer.


----------



## Service Call (Jul 9, 2011)

hotron said:


> Hey! you may what to go up on the gauge of the wire..for example..if your using #12 awg up to #10 because of the distance.:thumbsup:and yes ground to main panel if there is no sub panel closer.


I've seen the wiring in the Bahamas 😲


----------



## Dennis Alwon (May 9, 2009)

Service Call said:


> I just got a whirlpool bathtub and the instructions even state to run a separate #8 back to the panel. I'm not doing it. It even calls it an extra ground.


The manufacturers are doing whatever they want and it irks me that we are obligated to follow their instructions even when the NEC allows less. I have never run a #8 back to a panel. The equipotential bonding is to keep all areas around the tub at the same potential thus eliminating stray voltages-- well not eliminate them but make it so you can't feel it.


----------



## wlweston (Jul 21, 2010)

*to hotron*

Listen to Dennis and myself. I'm not sure what Dennis qualifications are, but he is right on. My qualifications??? I taught the NEC for 16 years at the local Community College for the apprenticeship program, Code update classes for over 3000 electricians for their license renewals, and am a member of the IAEI. I don't know it all, but have a pretty good handle on what is correct.


----------



## wavector (Nov 10, 2009)

Dennis Alwon said:


> The manufacturers are doing whatever they want and it irks me that we are obligated to follow their instructions even when the NEC allows less. I have never run a #8 back to a panel. The equipotential bonding is to keep all areas around the tub at the same potential thus eliminating stray voltages-- well not eliminate them but make it so you can't feel it.


Exactly, and why I think bonding to the rebar nearest the motor would be the right choice.

http://hibp.ecse.rpi.edu/~connor/education/Fields/IEEEStd142_2007.pdf

http://ecmweb.com/bonding-amp-grounding/grounding-vs-bonding-part-11-12



> *Grounding vs Bonding — Part 11 of 12*
> 
> Don’t let the bonding and grounding requirements of pools make you feel like you’re in over your head*Find more from this series on Grounding vs Bonding*
> 
> ...





> One impetus for developing this chapter is the misunderstood  "isolated ground." The standard states, "there is no real isolation between electrodes." It goes on to say the earth has a resistance, and you must consider the earth an electrical element (e.g., impedance) in an electrical circuit.
> 
> 
> The standard states that "there is always a current flowing in the earth, which produces voltage differences in electrodes - even a few feet apart. Not only are there differences, but these differences vary from second to second, particularly in an electrical storm."
> ...


----------



## Dennis Alwon (May 9, 2009)

wavector said:


> Exactly, and why I think bonding to the rebar nearest the motor would be the right choice.
> 
> http://hibp.ecse.rpi.edu/~connor/education/Fields/IEEEStd142_2007.pdf
> 
> http://ecmweb.com/bonding-amp-grounding/grounding-vs-bonding-part-11-12


In most cases there is no rebar for hydromassage tubs as I was mentioning above. Hydromassage tub is not a hot tub- different rules.

Even with hot tubs I usually don't see rebar installed in the pads- not around here anyway so we just do the alternate of encircling the tub with a #8 wire and tying it to the motor.


----------



## wavector (Nov 10, 2009)

Dennis Alwon said:


> In most cases there is no rebar for hydromassage tubs as I was mentioning above. Hydromassage tub is not a hot tub- different rules.
> 
> Even with hot tubs I usually don't see rebar installed in the pads- not around here anyway so we just do the alternate of encircling the tub with a #8 wire and tying it to the motor.



Sounds good to me. What I'm talking about is bring one up from the slab during the slab rough at the same time the ufer ground is brought out for the service. It's enforced in the county and city of Mobile, AL.


----------



## Dennis Alwon (May 9, 2009)

wavector said:


> Sounds good to me. What I'm talking about is bring one up from the slab during the slab rough at the same time the ufer ground is brought out for the service. It's enforced in the county and city of Mobile, AL.


Sure the service ufer is done that way but a pad poured for a hot tub away from the building is different. The ufer has nothing to do with the hot tub but rather only gets connected to the service. The tub usually has it's own pad and generally does not have rebar. They cannot make you install rebar in the slab so installing a circle of #8 around the tub 18-24 inches from the inside wall of the tub and put it 4-6 inches deep and connect to the tub motor is all that is required. The equipment grounding conductor for the tub takes it back to the panel. The equipotential bonding is only to keep the tub and the earth around it at the same potential.

Also many areas have adopted the TIA and often no bonding is required.




> 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.
> 
> ...


----------



## inspector1 (May 12, 2011)

Perhaps another thread should be titled, " Should Electrical Inspectors Be Fired For Requiring a #8 Copper Conductor To Be Installed Back To The Electrical Panel For Hot Tubs Or Hydromassage Bath Tubs"?


----------



## Pete m. (Nov 19, 2011)

inspector1 said:


> Perhaps another thread should be titled, " Should Electrical Inspectors Be Fired For Requiring a #8 Copper Conductor To Be Installed Back To The Electrical Panel For Hot Tubs Or Hydromassage Bath Tubs"?


C'mon man... if you fired all the electrical inspectors who would make up the rules?

Pete


----------



## Dennis Alwon (May 9, 2009)

inspector1 said:


> Perhaps another thread should be titled, " Should Electrical Inspectors Be Fired For Requiring a #8 Copper Conductor To Be Installed Back To The Electrical Panel For Hot Tubs Or Hydromassage Bath Tubs"?


Well I wouldn't go that far but I would try and educate them on the matter.


----------



## electricmanscott (Feb 11, 2010)

wlweston said:


> Listen to Dennis and myself. I'm not sure what Dennis qualifications are, but he is right on. My qualifications??? I taught the NEC for 16 years at the local Community College for the apprenticeship program, Code update classes for over 3000 electricians for their license renewals, and am a member of the IAEI. I don't know it all, but have a pretty good handle on what is correct.


Oh thank heavens!


----------



## inspector1 (May 12, 2011)

Dennis Alwon said:


> Well I wouldn't go that far but I would try and educate them on the matter.


If a police officer gave you a ticket for doing 30mph in a 40mph zone because he or she thinks it should be 25mph is making up a law. It seems to me that an inspector requiring a #8 back to the panel, is making his own rule. Occasionally, the installation instuctions may have the "check with the AHJ..." But, unles there is a local amendment requiring this, enforcement would be wrong. How many decades should it take to educate an inspector on this issue?


----------



## Service Call (Jul 9, 2011)

What if the inspector asked for the installation instructions and it says to run a #8 back to the panel for a "secondary ground".


----------



## backstay (Feb 3, 2011)

Service Call said:


> What if the inspector asked for the installation instructions and it says to run a #8 back to the panel for a "secondary ground".


Then you better install it to manufactures specs.


----------



## inspector1 (May 12, 2011)

Service Call said:


> What if the inspector asked for the installation instructions and it says to run a #8 back to the panel for a "secondary ground".


I already addressed this in my earlier post. Occassionaly the directions may reference to check with the AHJ. But unless the jurisdiction has a local amendment requiring the #8(highly unlikely), it is not required. Now, perhaps there is a manufacturer that requires it as part of the listing and labeling, then it should be enforced as an installation requirement.


----------

