Grounding Whirlpool Tub

[infinity]

When he says all the plumbing does he mean the supply as well, here in the Peoples Republic of Massachusetts there has not been a significant change to plastic plumbing yet,.. at least not in my little conner. If there is metallic water pipe there should be a bonding wire to it from the motor.

floaters are gross.

Why would a bond to the water pipe be required? Is the water pipe part of the circulation of the water?

 

[M. D.]

680.74. I think the bonding requirement requires interconnection between metal piping systems and metal parts associated with the water recirculating system at the tub location .

The pump motor is metal and if the piping system is metal and it is in the same location ,... why would it not require bonding????

 

[infinity]

680.74. I think the bonding requirement requires interconnection between metal piping systems and metal parts associated with the water recirculating system at the tub location .

The pump motor is metal and if the piping system is metal and it is in the same location ,... why would it not require bonding????

I fill up the tub and shut off the water. Now I turn on the pump and it recirculates it. How are the two connected?

680.74 Bonding.
All metal piping systems and all grounded metal parts in contact with the circulating water shall be bonded together using a copper bonding jumper, insulated, covered, or bare, not smaller than 8 AWG solid.

 

[al hildenbrand]

There is no support structure or access panel that I've seen; all that's there is the tub..

The tub has to be installed in a manner that permits the motor to be removed and replaced. Since, as I understand your description, there is no skirt included with the tub, one will be built by the carpenter or someone else. An access has to be framed in. The access might be on the other side of the wall that the motor is against. Or, if the tub is recessed into the floor, the access may be in the ceiling below.

This takes a bit of time to figure out, with the general, or lead carpenter, or home owner; as electrician, plumber and tub, all three, have a stake in the placement of the access.

I generally place the homerun with a generous tail, raise the question to the appropriate folks in control of the job, and finish it up at the end of the rough.

One other thought, you can use a dead front GFI placed out in the bathroom to protect the motor receptacle. If the HO wants a little more control in the matter, it can be sold as giving him/er the ease to reset the GFI without openning the access.

 

[M. D.]

Infinity , I see your point. However I'll still bond the motor to the copper water pipe to create an equpotential plane between the piping system feeding the tub and the grounded metal motor whether or not I know if there is any grounded metal in contact with the ciculating water within the pump. Better safe than sorry.

How would you know there is no grounded metal in contact with the circulating water inside the pump ??

Is it your opinion that both the piping system and the grounded metal pump
have to be in contact with the circulating water?

 

[George Stolz]

How would you know there is no grounded metal in contact with the circulating water inside the pump ??

Metal that isn't in contact with the EGC of the pump itself?

Is it your opinion that both the piping system and the grounded metal pump have to be in contact with the circulating water?

Any metal piping system in contact with the circulating water is to be bonded.

Any metal piping system not in contact doesn't.

See the 2005 Report on Comments that changed this:

________________________________________________________________
17-183 Log #732 NEC-P17 Final Action: Accept in Principle
( 680.74 )
________________________________________________________________
Submitter: Gary Siggins, Underwriters Laboratories Inc.
Comment on Proposal No: 17-152
Recommendation: The Panel Statement regarding the rejection of proposal
17-152 indicated they believed a double insulated whirlpool bath pump provided
an increased level of safety. Although this is the case for above ground
storable and non-storable swimming pool pumps, I believe it is not the case
with whirlpool baths utilizing double insulated pumps. The pump designs and
their installations are different.
Whirlpool bath pumps are not accessible by the bathtub occupants and are
required by UL 1795 to have their live parts above the mounting service in the
event of a leak. They are also required to have their internal metal parts that
might become energized in a failure (the motor shaft in particular) isolated
from the water. An internal failure of the motor would not produce the same
hazards as an outdoor storable pool unit that is accessible and may have wet
surfaces. The grounding of internal dead metal parts, therefore, is not needed.
Due to the requirements on the double insulated bathtub pumps and their
mounting in UL 1795, the text from 680.74, ?and providing a means for
grounding internal nonaccessible, non-current carrying metal parts? should,
therefore, be deleted.
Substantiation: Present text requires substantial modification of the pump
motor without an overall increase in the safety of the complete whirlpool bath.
Panel Meeting Action: Accept in Principle
Revise 680.74 to read as follows:
680.74 Bonding. All metal piping systems and all grounded metal parts in contact
with the circulating water shall be bonded together using a copper bonding
jumper, insulated, covered, or bare, not smaller than 8 AWG solid.
Panel Statement: The need for bonding in a bathroom differs from the need
for bonding in a pool area. Electrical equipment of a hydromassage bathtub is
not accessible to users of the tub. Only parts that can cause a voltage gradient
in the bathtub need to be bonded. Section 680.74 has been concisely reworded
to require the bonding of only the parts that present a risk of creating voltage
gradients in the hydromassage bathtub. The panelʼs action on 17-183 supersedes
the panelʼs action on ROP 17-153.
Number Eligible to Vote: 10
Ballot Results: Affirmative: 10

 

[infinity]

Is it your opinion that both the piping system and the grounded metal pump
have to be in contact with the circulating water?

IMO the recirculating system piping must be metallic to require the #8 bonding conductor. All of the tubs that I've seen lately have circulation systems that are entirely plastic. Internal metal part of the pump are already connected to the EGC in the cord and do not require anything else. The metallic water piping system feeds the tub faucet is not connected to the water circulation system.

 

[M. D.]

Thanks george, that was good reading , do you have a link for more of that stuff ? Though I must say I'll be hard pressed to not bond the two

 

[George Stolz]

Thanks george, that was good reading , do you have a link for more of that stuff ? Though I must say I'll be hard pressed to not bond the two

Sure, go over to the NFPA site for all the ROP's and ROC's.

For searching purposes, I am going to say something outlandish so I can find this again: The grey goose flies at midnight.

Maybe now I can find it without having to go through their web site.