Bonding In-Ground Pool with Plug-In Pump

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timothyjblairjr

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Massachusetts
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Forgive my ignorance as I am trying to understand my existing pool's electrical system.
The case is an in-ground swimming pool with an existing bonding grid and a 220V circuit from the main panel supplying power to the pool pump. The circuit contains two hot conductors and a grounding conductor that run from the main panel via conduit to a single-throw switch in a metal box that is protected with a weatherproof enclosure. From the switch, they run to an adjacent 4x4 metal box with a 20-amp twist lock receptable, also in a metal box with a weatherproof enclosure. Both the switch box and the receptable box are grounded. This is all happening at the equipment pad. The pump is fitted with a 3-foot long chord at the end of which is the mating 20-amp twist lock plug. The #8 bonding wire exiting out of the ground from beneath the pool deck is connected to the pump motor housing at a grounding lug and also spliced with an in-line zinc anode for saltwater generating system. Presumably, when the pump is unplugged, there is no longer an intimate connection between the pool bonding grid and a grounded conductor that ties back to the service. My questions is: does this matter? Should the bonding wire that is connected to the motor housing somehow also be permanently connected to the grounding conductor on the line side of the circuit, so that even if the pump is unplugged the bonding grid connection isn't lost?
 
The bonding grid does not need, and is not required, to run back to the panel or tied to the system grounding. The grid, by default, will tie to the grounding system via the EGC of any electrical equipment that is bonded. If the pump is unplugged, the bond is still intact but will lose connection to the system ground, but is not required to connect to it anyway. Also, if the pump is not plugged in, there is nothing to cause a fault. The bonding grid is not to clear faults, it is just to make everything in and around the pool the same potential.
 
I would treat this as required for a double insulated pool pump.
680.26(B)(6)(a)
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.
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Little Bill said:
The bonding grid does not need, and is not required, to run back to the panel or tied to the system grounding. The grid, by default, will tie to the grounding system via the EGC of any electrical equipment that is bonded. If the pump is unplugged, the bond is still intact but will lose connection to the system ground, but is not required to connect to it anyway. Also, if the pump is not plugged in, there is nothing to cause a fault. The bonding grid is not to clear faults, it is just to make everything in and around the pool the same potential.
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Bill -
Little Bill said:
The bonding grid does not need, and is not required, to run back to the panel or tied to the system grounding. The grid, by default, will tie to the grounding system via the EGC of any electrical equipment that is bonded. If the pump is unplugged, the bond is still intact but will lose connection to the system ground, but is not required to connect to it anyway. Also, if the pump is not plugged in, there is nothing to cause a fault. The bonding grid is not to clear faults, it is just to make everything in and around the pool the same potential.
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Bill - Thanks for that explanation. So it just boils down to the difference between grounding and bonding. In the case of the pump being unplugged, it would still be bonded but it wouldn’t be grounded (which it wouldn’t need to be if it was unplugged). Am I understanding correctly, or correctly enough?
 
timothyjblairjr said:
Bill -

Bill - Thanks for that explanation. So it just boils down to the difference between grounding and bonding. In the case of the pump being unplugged, it would still be bonded but it wouldn’t be grounded (which it wouldn’t need to be if it was unplugged). Am I understanding correctly, or correctly enough?
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Correct
 
timothyjblairjr said:
Don - I’m having trouble following that code statement. Are you saying that you would splice an additional #8 bonding wire to the existing #8 that is on the motor housing and attach it directly to the 240 circuit’s EGC somewhere?
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If your pump is not double insulated then you wouldn't need to do this. I think that rule has two reasons:
1). In case the pump is ever replaced with one that has an EGC and is not double insulated
2). If the double insulation failed during a fault, you would have a connection to the circuit EGC through the bond wire

If a pump is unplugged, there would be no fault from the pump.
 
I may be wrong, but my bonding wire is continuous solid #8 and no splices. From the rebar, pool light, pool pump, heater and to all the fixtures.
 
timothyjblairjr said:
Don - I’m having trouble following that code statement. Are you saying that you would splice an additional #8 bonding wire to the existing #8 that is on the motor housing and attach it directly to the 240 circuit’s EGC somewhere?
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It requires you to pull an EGC with the circuit conductors for the double insulated pump, and where there is no other connection between the electrical grounding system and the pool bonding system, you tie the two together at the double insulated pump. The pump EGC does not have to be 8 AWG, it is sized per Table 250.122.
 
Unplugged motor is just a piece of metal and some wires. I don't think the code apply to an unplugged motor.
 
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