Reading other posts about people feeling a shock in the pool, the question often comes up about what is touching the water. This got me thinking, I have a Stenner pump that may have continuity to he water through the bleach that it's injecting. Should the Stenner be bonded, and if so, where? I don't recall seeing a bonding lug.
Does a Stenner Pump Need Bonded?
- Thread starter 440dodge440
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Perhaps in the strictest terms it should have a bond but as you said there is no lug. I would not worry about it, the power cord has a ground lug and the pool bond does meet the ground at some point. Besides unlike a pool pump there is no metal in the distribution of the liquid being pumped, it is all contained in materials that will not conduct electricity. As long as the Stenner is connected to a GFCI outlet and you have not removed the ground lug you should be safe.
Great question.
The full response would get very technical. Let's just say that the equipotential bonding requirements in the code are really internally consistent nor are they consistent with the grounding provisions of the code.
The NEC does not specifically require bonding of a Stenner pump. It requires bonding of "metal parts of electrical componants associated with the circulating system of the pool." NEC. 680.26 (B) (6). While a Stenner pump has some metal parts it really has no exposed metal parts. A SWC is actually integrated into the circulation system of the pool so it gets a bonding lug. So I don' t think the code requires they be bonded.
More importantly the pump itself is insulated from the pool water by the plasic tube. The motor and pump assembly are also separated by plastic parts. So the risk of a stray current traveling from the motor to the chlorine is very low. Now if it's all wet like in a thunderstorm all bets are off.
Bonding is not grounding. While the equipotential bonding system may have an indirect connection to the equipment bonding conductor, because for example the circulation pump cover is both bonded and grounded, this does not mean that grounded components are equipotentially bonded. The equipotential bonding system is a zero or no resistance system. It uses large diameter wire and listed screw connections to create a system with close to zero resistance. The equipment grounding conductor is not constructed that way, it uses wire nuts and under some circumstances conduit and the building structure as integral elements. Moreover, generally you don' t want the bonding system and grounding conductor to meet. This introduces the possibility of current throughout the bonding system in the event of a fault in any element protected by that equipment grounding conductor. The pool construction industry won a major concession here in the 2017 code, it only requires insulated grounds in corrosive enviroments rather than all areas associated with a pool.
The full response would get very technical. Let's just say that the equipotential bonding requirements in the code are really internally consistent nor are they consistent with the grounding provisions of the code.
The NEC does not specifically require bonding of a Stenner pump. It requires bonding of "metal parts of electrical componants associated with the circulating system of the pool." NEC. 680.26 (B) (6). While a Stenner pump has some metal parts it really has no exposed metal parts. A SWC is actually integrated into the circulation system of the pool so it gets a bonding lug. So I don' t think the code requires they be bonded.
More importantly the pump itself is insulated from the pool water by the plasic tube. The motor and pump assembly are also separated by plastic parts. So the risk of a stray current traveling from the motor to the chlorine is very low. Now if it's all wet like in a thunderstorm all bets are off.
Bonding is not grounding. While the equipotential bonding system may have an indirect connection to the equipment bonding conductor, because for example the circulation pump cover is both bonded and grounded, this does not mean that grounded components are equipotentially bonded. The equipotential bonding system is a zero or no resistance system. It uses large diameter wire and listed screw connections to create a system with close to zero resistance. The equipment grounding conductor is not constructed that way, it uses wire nuts and under some circumstances conduit and the building structure as integral elements. Moreover, generally you don' t want the bonding system and grounding conductor to meet. This introduces the possibility of current throughout the bonding system in the event of a fault in any element protected by that equipment grounding conductor. The pool construction industry won a major concession here in the 2017 code, it only requires insulated grounds in corrosive enviroments rather than all areas associated with a pool.
Though Swg must be bonded at the power supply/logic panel
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Thanks...I guess it's a moot point since there is no place to bond it. Most of the time I figured it was safe since there is no direct path to the water. My main concern was about current travelling through the liquid bleach when the Stenner was running, to the injection point at the water. Now that I think about it, it may be isolated even when running if there is no continuous volume of bleach in the supply tube.