Mike, please read the change submitted in post #14 and read the comments and the vote.
I don’t see how a mixing valve in the tub that is plumbed with plastic would be in contact with the metallic piping.
IMO the CMP was pretty clear that their intention is to bond only the metal piping systems that contains the circulation water. Even though as Mike pointed out there could hypothetically be a time when the fill water is in contact with the tub water the CMP chose not to require anything beyond the circulation system as requiring the bonding.
I don’t think I has ever seen a tub with metallic piping under the skirt as part of the tub.
Mike, hypothetically, if the metallic piping was bonded to the motor how would this be any safer? The person cannot touch the piping in the wall or under the skirt and as I said above all the piping I have seen under the skirt is plastic.
There are a couple of things that we need to keep in mind here.
First as Home Inspectors we are interested in the protection of our clients and even point out GFCI protection in homes that were built before the requirement. This would leave out any debate as to what the intent of any code section means during a debate.
Second the proposal is for a code that hasn’t been printed as yet and anyone knows that we have a couple of other stages to enter before it goes to print such as the comment stage and any appeals that come about. The comments will not be available until March of next year and these will change a lot of proposals.
Third a careful reading of the panel statement shows that the only part of the proposal that was accepted was the word “BOTH” and the rest of the existing section stays intact.
There seems to be this hang-up about the circulating water and the train of thought that this means the water that is in the tub. There is no consideration given to how this water gets into the tub or the fact that more water can be added to the tub while in use.
Then there seems to be a large misunderstanding of the purpose of this bonding. Here is what the NEC Handbook has to say about this matter.
As one can see this bonding is done to keep everything at the same touch potential for the safety of the user of the tub.
The mixing valve that is used to fill the tub needs to be at the same touch potential as the water in the tub and there is only one way this can be accomplished, through the bonding.
We all know that the NECH not code and merely an opinion, I mostly agree with what the NECH authors espouse but not always. Also this is not a pool or a spa, it’s a hydromassage tub. I agree that the use of the words equipotential bonding in 680.74 is confusing because this has a specific meaning elsewhere in that article. However there a no requirement for equipotential bonding for metal parts in proximity to a hydromassage tub.
Then explain this;
Anywhere there is a body of water and electricity is being used where the person can come in contact with the water an EBG is required. This is the sole purpose of the #8 mentioned in 680.74
If it was being installed to clear a fault then the conductor would be sized by Table 250.122 and be based on the size of the branch circuit conductors supplying the motor.
Look at the top right of this slide and see who made it and then explain why.
That article in the IAEI publication is incorrect. They like anyone else can get things wrong. Even one of the comments in the online version says so. I know that 680.74 is poorly written and the proposal for the 2014 NEC was an attempt to clear up the confusion. IMO it does so but maybe a re-write of 680.74 for the 2017 is needed.
I would also say that anyone can be incorrect. I know that I have been on several occasions throughout my life.
Even if one finds 680.74 hard to understand the Scope of 680 is very clear.
Again we must understand just what the purpose of the #8 solid copper conductor is supposed to accomplish. If you don’t think that it is for the purpose of establishing an EBG please explain what you think the purpose of it is.
For the record I don’t think that the slide is incorrect. I do think that for the most part people just don’t understand the EBG that is required around any body of water be it a swimming, wading, therapeutic, and decorative pools; fountains; hot tubs; spas; or hydromassage bathtubs.
I see nothing in 680.74 that requires equipotential bonding like that of a pool in Article 680. In fact 680.74 is a stand alone requirement and is not required to apply other parts of the article especially those of 680.26.
I have opened a new debate on this over at your home site to see how it goes there.
LOL…I guess I will keep my opinion out of this one. Ironically, I believe the wording is clear on what you do and anything in a 2014 proposal is yet to make it past the meetings in California…I will be there any article 680 is assigned to me for reporting.
We will see how it flushes out.
Added:
“To properly apply the NEC, you must understand the safety-related issue of the rule and then apply common sense. NEC terms and concepts The Code uses many technical terms and expressions. It’s crucial that all Code users understand the meanings of basic technical and Code terms such as ampere, backfed, induction, raceway, etc. to understand how to apply the rule itself. It is not only the technical words that require close attention in the NEC; even the simplest words can make a big difference. The word “or” can imply alternate choices for equipment, wiring methods, and other requirements. Sometimes “or” can mean any item in a group. The word “and” can be an additional requirement, or any item in a group”
680.74 Bonding (from 2011 National Electrical Code Handbook-McGraw-Hill Edition)
All piping systems and all metal parts in contact with the cir-
culation system must be bonded with a 8 AWG solid copper bonding conduc-
tor, connected to the bonding terminal on the motor. Double-insulated motors
are exempt from this requirement. However, the bonding conductor must be
run to the pump location, long enough to bond a conventional, non-DI motor if
one is purchased to replace the original. This is the same principle as that used
in 680.26(A)(6)(a) for permanently installed pools. Note that the requirement is
to bond piping systems. With todays increasing use of nonmetallic water pip-
ing systems there is frequently nothing to bond under the skirt anyway. A metal
escutcheon around the faucet with no metal piping behind it is not a metal pip-
ing system. It is very possible that even with a motor with a bonding lug, there
will be no opportunity to run a bonding conductor. A bond wire must bond at
least two things, and increasingly, there is no second item requiring bonding.
Neither is it required to run a bonding conductor to the panel or anywhere else.
Refer to the bonding discussion at 680.26 for the reasons why this is so.
That pump has a metal shaft and it is contact with the circulating water.
I say bond it
Lol…oh please…lol…bond a insulated pump …ok
That is addressed in the design of the motor and noted by the term “double insulated”. It is the same basic provision that allows the majority of hand tools not to have a ground wire.
Ever look at the attachment plug of your reciprocating saw, drill, grinder, etc? They have no ground prong because they are double insulated.
I have a question…The metal drain of many whirlpools is in contact with the circulating water. Should bonding with #8 copper be required between the pump motor case and the metal drain. Most copper supply lines are not in contact with the circulating water.
Since a metal drain of a Whirlpool tub is in contact with the circulating water, should the metal drain be bonded to the pump motor grounding lug?
