Spa Motor Grounding

[spark master]

The extra lug on a spa motor, pool pump motor.... That goes to ground. What is the theory behind that ? A redundant path for ground fault current ?? or is it bring the ground plane up to the stray voltage potential ?

I'm trying to wrap my head around this, and get into swimming pool theory. I started watching some of the on-line videos, which are truly educational.

 

[ActionDave]

The latter.
It is an equal potential bonding connection that goes to all the metal parts in the spa and sometimes the grid in the dirt. It is not an equipment grounding conductor, has nothing to do with clearing a fault, and does not get tied into the panel.

 

[cuba_pete]

Ever hold onto a motor casing that wasn't bonded?

We used to do this with old disk drive motors (think 1970's) when we accidentally discovered that the static field generated by them would cause your hands to clamp down so you could barely let go. What a rush!

 

[spark master]

I'm working on a whirlpool tub in a house. Big master bathroom. The pump motor has a bonding lug. So I ran a #8 wire from the lug, all the way back to the water main. But now I'm thinking. Wouldn't it be better to run it to the copper piping just under the tub ? This way the tub faucet is bonded to the tub motor at a closer distance ??

I went back to the water main, because there are plastic water filters in the plumbing system. So most of the internal plumbing is not really at ground potential.

 

[iwire]

The motor is already grounded via an EGC back to the panel. You do not run another conductor from the lug on the pump to the panel.

As Dave pointed out that is supposed to connect to the bonding system at the pool or tub.

 

[Dennis Alwon]

I'm working on a whirlpool tub in a house. Big master bathroom. The pump motor has a bonding lug. So I ran a #8 wire from the lug, all the way back to the water main. But now I'm thinking. Wouldn't it be better to run it to the copper piping just under the tub ? This way the tub faucet is bonded to the tub motor at a closer distance ??

I went back to the water main, because there are plastic water filters in the plumbing system. So most of the internal plumbing is not really at ground potential.

I believe you anre talking about a hydromassage tub. This has different rules in article 680 then spas...

 

[infinity]

I'm working on a whirlpool tub in a house. Big master bathroom. The pump motor has a bonding lug. So I ran a #8 wire from the lug, all the way back to the water main. But now I'm thinking. Wouldn't it be better to run it to the copper piping just under the tub ? This way the tub faucet is bonded to the tub motor at a closer distance ??

I went back to the water main, because there are plastic water filters in the plumbing system. So most of the internal plumbing is not really at ground potential.

As Dennis stated this is a hydromassage tub not a spa as mentioned in the OP so the rules are different. Your #8 conductor is not required to run back to the water main or to the copper plumbing feeding the tub.