Hydro massage bathtubs - Bonding

[sw_ross]

Have a hydromassage bathtub install. It needs 2-20 amp circuits (1- each, circ pump, and heater).

The framework of the unit has a bonding lug. 680.74 talks about bonding parts together within the unit with an 8awg solid copper bonding jumper. It says that the bonding jumper is not required to go back to the panel board or service equipment.

The guy I’m working with wants to run an 8awg thhn wire back to the panel. Is this required?
I’m not sure what to do with this bonding lug?
Obviously there is going to be an EGC with the branch circuits.
Thanks

 

[Dennis Alwon]

If copper water lines are feeding the tub then run a jumper from the lug to the pipes otherwise do nothing.

 

[david]

he mentioned two circuits heater and water pump. the heater most likely has a lug for bonding to the pump even if the water supply is PEX or PVC

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[augie47]

You might want to check your manufacturers instructions... it's been a while but at one time some hydros I inspected required a bond from the heater to the service panel. (I've not seen that requirement on motors, just on heaters)

 

[Dennis Alwon]

You might want to check your manufacturers instructions... it's been a while but at one time some hydros I inspected required a bond from the heater to the service panel. (I've not seen that requirement on motors, just on heaters)

The op says

The framework of the unit has a bonding lug. 680.74 talks about bonding parts together within the unit with an 8awg solid copper bonding jumper. It says that the bonding jumper is not required to go back to the panel board or service equipment.

I have never run it back to the panel even if the tub instructions stated it. I never checked to be honest but if the NEC doesn't require it for pools then I certainly don't see a need for it on a hydromassage tub

 

[augie47]

The op says



I have never run it back to the panel even if the tub instructions stated it. I never checked to be honest but if the NEC doesn't require it for pools then I certainly don't see a need for it on a hydromassage tub

What ?? Now you expect me to read the OP thoroughly ?

 

[sw_ross]

Thanks! It makes sense that if there’s copper plumbing to bond to.
I also thought about looking at the installation instructions,…. Maybe I should do that!

 

[kwired]

The lug is supposed to be for equipotential bonding of items in the vicinity if necessary. The branch circuit Equipment Grounding conductor is sufficient for "equipment grounding" and is only thing that needs connected back to the supply panel for grounding purposes.

Some sort of add on heater would be something that needs a bond between the pump and heater. A unit already equipped with heater you would think would already have such a bond when necessary.

 

[augie47]

It depends on manufacturer an available bonding point.
An example is this wording from a mirabelle hydro heater instruction sheet:
With a No.8 solid copper wire, bond the heater and hydro massage bathtub pump to the
homes electrical panel or approved local bonding point. A bonding lug has been provided on the
heater.

 

[kwired]

It depends on manufacturer an available bonding point.
An example is this wording from a mirabelle hydro heater instruction sheet:
With a No.8 solid copper wire, bond the heater and hydro massage bathtub pump to the
homes electrical panel or approved local bonding point. A bonding lug has been provided on the
heater.

I think manufacturers that state that don't understand the intent of the lug, it is not for grounding it is for bonding other items in the tub vicinity to provide voltage equipotential from tub to those items.

 

[david]

I think manufacturers that state that don't understand the intent of the lug, it is not for grounding it is for bonding other items in the tub vicinity to provide voltage equipotential from tub to those items.

however, it is required to bond to the pump motor branch circuit equipment ground, even when the pump is double insulated.

same that is required for swimming pools



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[kwired]

however, it is required to bond to the pump motor branch circuit equipment ground, even when the pump is double insulated.

same that is required for swimming pools



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This is usually already accomplished by the EGC that is part of supply conductors/cord/cable to the pump motor.

If pump is double insulated you don't need to bond the pump, you still need something bonded to the EGC that also gives provisions for equipotential bonding connection to other items.

 

[david]

the question asked when it is double insulated how is this done.

I guess I would leave a tail of the branch circuit EG at the pump rec. stick out of the device box and split bolt the # 8 TO it

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[Dennis Alwon]

This is usually already accomplished by the EGC that is part of supply conductors/cord/cable to the pump motor.

If pump is double insulated you don't need to bond the pump, you still need something bonded to the EGC that also gives provisions for equipotential bonding connection to other items.

Not sure about that.

680.26(B)(6)(a)exception

Double-Insulated Water Pump Motors. Where a double-insulated water pump motor is installed under the provisions of this rule, a solid 8 AWG copper conductor of sufficient length to make a bonding connection to a replacement motor shall be extended from the swimming pool equipotential bonding means to an accessible point in the vicinity of the pool pump motor. Where there is no connection between the swimming pool equipotential bonding means and the equipment grounding system for the premises, this bonding conductor shall be connected to the equipment grounding conductor of the motor circuit.

 

[david]

680.74 (B) calls out the Equipment Ground for the double insulated pump branch circuit

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