Spa Tubs

[HankShadwell]

I inspected a spa tub whose pump motor had a ground lug attached. Electrician did not bond the motor housing and insists that 680.74 says the ground lug is for all the grounded metal parts (copper supply pipes) and not necessary when water pipes are non ferrous (plastic). I don't see that. The pump is not double insulated. If the pump has a ground lug attached, my take is that the manufacturer put it there to ground the motor frame. Can you comment?

 

[Dennis Alwon]

I am assuming this is a hydromassage tub that is in the bathroom and you fill it whenever you use it. If that is the case then I agree that if the water pipe is plastic then no bonding to the lug is necessary.

 

[infinity]

I agree with Dennis. No bonding needed even if it had copper water lines.

 

[Dennis Alwon]

I agree with Dennis. No bonding needed even if it had copper water lines.

Trevor what about 680.74. I read that to be that metal water pipes should be bonded to the metal parts of the circulating system- the pump is one of them

 

[infinity]

Bonding is required for metal water pipes that are part of the water circulation system not those used to fill the tub. The 2014 NEC should clear this up.

 

[Dennis Alwon]

Bonding is required for metal water pipes that are part of the water circulation system not those used to fill the tub. The 2014 NEC should clear this up.

That was discussed at our meeting this year . Can't remember which CMP member answered the question but I understood him to say if there is metal water pipe feeding the tub then it needs to be bonded to the tub

 

[infinity]

That was discussed at our meeting this year . Can't remember which CMP member answered the question but I understood him to say if there is metal water pipe feeding the tub then it needs to be bonded to the tub

Was it someone from CMP17? They agreed to a wording change in 2014 to clear up the confusion.

 

[Fliz]

Was it someone from CMP17? They agreed to a wording change in 2014 to clear up the confusion.

Really curious about this. Are they clearing the confusion to say that the supply pipes shall be
bonded, or to say that only the "circulating" pipes need to be bonded, where "circulating" refers only to those parts involved with when the motor is pumping water around the tub and not the
supply pipes?

 

[Dennis Alwon]

I don't remember what panel or who it actually was that stated it but here is the 2014-- not sure this clarifies things or not

680.74 Bonding. Both metal piping systems and grounded metal parts in contact with the circulating water shall be bonded together using a solid copper bonding jumper, insulated, covered, or bare, not smaller than 8 AWG. The bonding jumper shall be connected to the terminal on the circulating pump motor that is intended for this purpose. The bonding jumper shall not be required to be connected to a double insulated circulating pump motor. The 8 AWG or larger solid copper bonding jumper shall be required for equipotential 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 any electrode.
The 8 AWG or larger solid copper bonding jumper shall be long enough to terminate on a replacement nondouble- insulated pump motor and shall be terminated to the equipment grounding conductor of the branch circuit of the motor when a double-insulated circulating pump motor is used. [ROP 17–148]

 

[augie47]

There is one small 'fly in the ointment'.
Depending on how the inspector addresses 110.3(B) in regard to installation instructions, the "Jacuzzi' brand of hydrotub still has, as part of it's install instructions, a requirement to bond the motor to the electrical panel or local bond with a #8.
All of the hydros I have inspected have had that requirement for the heater.

From the instructions:

[FONT=&quot]With a #8 solid copper wire, bond the heater to the house electrical panel or approved local bond. A bonding lug is provided on the heater. With another #8 solid copper wire, bond the pump/motor to the house electrical panel or approved local bond. A bonding lug is provided on the pump/motor.[/FONT]

 

[kwired]

Outside of what Gus mentioned, which I find pointless and have no idea why those instructions exist, I always thought that lug on the motor was for bonding anything necessary in the vicinity of the tub, including metallic water piping. The idea here is to ensure all these objects that are within reach of a user are at same potential more so than ensuring they are grounded (IMO). Being grounded certainly doesn't hurt anything, but that is what the EGC is for that is run with the branch circuit conductors.

I also have been thinking that if we have a packaged unit that is listed as is, why should we need to bond metallic water circulating piping? Shouldn't that have been done at the factory?

 

[infinity]

I don't remember what panel or who it actually was that stated it but here is the 2014-- not sure this clarifies things or not

In the 2014 it seems pretty clear that the requirement is only for metal piping systems in contact with the circulation water. The substantiation, which the CMP agreed with, stated that the clarification/change was necessary because of the large amount of misinterpretation of the old wording.

 

[Dennis Alwon]

There is one small 'fly in the ointment'.
Depending on how the inspector addresses 110.3(B) in regard to installation instructions, the "Jacuzzi' brand of hydrotub still has, as part of it's install instructions, a requirement to bond the motor to the electrical panel or local bond with a #8.
All of the hydros I have inspected have had that requirement for the heater.

From the instructions:

With a #8 solid copper wire, bond the heater to the house electrical panel or approved local bond. A bonding lug is provided on the heater. With another #8 solid copper wire, bond the pump/motor to the house electrical panel or approved local bond. A bonding lug is provided on the pump/motor.

I have never done that and to be honest I never will unless caught on it. I cannot imagine why that is there except for manufacturer hysteria. A swimming pool doesn't req. that so IMO it is a bogus rule. I hate the fact that we are suppose to use the manufacturers instructions as most that I have read are garbage. I know- I should follow it but that particular one I never have. To be honest I never have read the installation instructions for them. So if I don't read it then I am compliant- right...

 

[GoldDigger]

I don't remember what panel or who it actually was that stated it but here is the 2014-- not sure this clarifies things or not

...and grounded metal parts in contact with the circulating water shall be bonded together

And is that really saying that if you do not ground a metal part, you do not need to bond it? I thought that in most cases the bonding jumper is providing the ground as well.
I suppose they could be trying to say that other parts of the code require a metal part to be grounded, then this part requires a specific method of bonding in addition to that.:?

 

[Dennis Alwon]

I think if you have a hydromassage tub that has metal piping as part of the circulation system then you must bond the tub pump to the motor. I have never seen one that had metal circulation pipes but if it did I suspect it would be bonded from the factory.

This section must be written for people who try and custom build their own tubs.