Pool heat pump bonding question


Old 06-03-06, 06:34 AM
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Join Date: Apr 2005
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Pool heat pump bonding question

Hi Folks and Thank You in advance for your time-
I have a pool heat pump. It is 220v (three wires). I installed it last year by myself, including running the wiring from the service panel to the outside of the house using conduit in the house which transitions to a disconnect box on the outside of the house (code requirement), and from there I used carflex to the heat pump. The heat pump works great. However I think I might have made a mistake on the bonding. I took a #8 bare wire from the bonding lug on the heat pump and ran it to a grounding rod which I drove into the ground 8'. The pool pump is also attached to this grounding rod. Did I make a bad? I am thinking that somehow running to earth ground does not satisfy bonding requirements as I am unsure as to the possible resistance imbalance between earth ground and the service panel earth ground (separate grounding rods for the two). Any comments or suggestions? Thanks.
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Old 06-03-06, 06:43 AM
Join Date: Sep 2003
Location: Central New York State
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Yes, you made a mistake. The bonding lug on the heater, the bonding lug on the pump, and ALL metal within five feet of the pool must be bonded with #8 (or larger) copper wire. ALL metal means the rebar in any concrete, the metal of the pool, and ladder or railing - anything.

In some cases a ground rod is called for by the manufacturer and in some cases a local requirement might call for on, but generally not. If one is not required then one is not needed.
Old 06-03-06, 06:58 AM
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Ok-then what?

Hi Bob-
Thanks 4 your input. So what do I bond the heater and pump to, if not the earth ground rod I drove into the ground? These grounding lugs on the chassis of these units are attached how?
Old 06-03-06, 07:11 AM
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Originally Posted by argekay
So what do I bond the heater and pump to, if not the earth ground rod I drove into the ground?
Each other, that's it.
Bonding is NOT grounding.

Although this might be over the heads of some lay folks I will post the NEC Handbook commentary regarding pool bonding:

It is important to understand the difference between the terms bonding and grounding as they apply to Article 680. As defined in Article 100, bonding is ``the permanent joining of metallic parts to form an electrically conductive path that ensures electrical continuity and the capacity to conduct safely any current likely to be imposed.'' As described in 680.26(A), the function of equipotential bonding differs from the function of bonding to meet the requirements of Article 250 in that providing a path for ground fault current is not the function of the equipotential bonding grid and associated bonding conductors.
Creating an electrically safe environment in and around permanently installed swimming pools requires the installation of a bonding system with the sole function of establishing equal electrical potential (voltage) in the vicinity of the swimming pool. A person who is immersed in a pool or who is dripping wet, has a large amount of exposed skin, and is lying or walking on a concrete deck is extremely susceptible to any differences in electrical potential that may be present in the pool area.
The primary purpose of bonding in and around swimming pools is to ensure that voltage gradients in the pool area are not present. The fine print note explains that the 8 AWG conductor's only function is equipotential bonding to eliminate the voltage gradient in the pool area.
The reason for connecting metal parts (ladders, handrails, water-circulating equipment, forming shells, diving boards, etc.) to a common bonding grid [pool reinforcing steel, pool metal wall, or an alternative bonding grid as described in 680.26(C)(3)] is to ensure that all such metal parts are at the same electrical potential. The grid reduces possible injurious or disabling shock hazards created by stray currents in the ground or piping connected to the swimming pool. Stray currents can also exist in nonmetallic piping because of the low resistivity of chlorinated water.
Old 06-03-06, 08:24 AM
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Join Date: Apr 2005
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Got it.

Thanks Speedy Petey-
I understood that code excerpt. I must use a #8 to connect the pool heater, and pool pump to the bonding grid which exists around my pool. In case a hot wire touches the metal frame of any one of these components, the current will be safely directed away from the bathers. Thanks!

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