Spa Bonding at 300mV

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cuba_pete

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Washington State
Bonding

Bonding

i already posted the why's.
its a UL listed spa, my locale does not require bonding beyond what manufacturer has done. this means the water be gnd'd or bonded to the "bonding lug" the spa has.

there can in fact be a voltage generated by the free ions in the soup mix of chemicals in the water, and since the water from top to bond lug is a "variable resistor" i can measure a voltage diff.

i am more curious to know actual resistance, and for this i need to do a current test from water to bond lug.

but as you can see, the bonding doesnt completely fall in alignment with the definition of bonding, etc. the water should be at same potential as everything it is bonded to, but obviously wont be if the soupy battery (water) has resistence between it and the out or water bonding lug, etc.




plumbing? why would you worry about plumbing? almost every manufactured spa (if not all) has a heater that is a metal, that metal must be gnd'd, and the very conductive water touches the heater.

You are making these questions out to be more than intended, I think. You are also coming at the question from many different directions. For example, any electrical charge created by your "free ions in the soup mix of chemicals in the water"would not reference your NEC grounding and bonding.

It appears to me that you are looking for a result to a standard which does not exist for the very reason that one cannot exist (and therefore does not). The IEEE has researched the resistance of water in plastic plumbing in order to prove that plastic plumbing does not need bonding or jumpers around plastic sections. Tests in one case resulted in 110Kohms over one meter of 1/2" water-filled plastic piping which keeps currents very low and proves no need for bonding jumpers.

One problem there is that the ones who asked the question "why not" apparently do not understand fundamental electrical concepts such as plastic not conducting standard electrical household current...:blink:

Anyway, I was speaking of the internal plumbing in the spa in a general sense. Water cannot be used as a conductor, and that is why we bond metallic water piping at such-and-such distances, specify this/that side of the meter, unions, etc. The bond can only be as good as it is due to metallic bonding. We don't bond to the water or through the water so picking random measuring points in the water is pointless...especially due to the infinite variability of the water's chemical makeup.

I understand the intention of what you are doing, but ultimately your results could vary day by day...especially in a spa.

Case in point, refer to 680.26(C) (though this refers to pools not spas). Even though this sub-part states the requirements for an intentional bond to the water there is no measurement made to ensure a certain gradient is measured. It's a one-size fits all approach.
 
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