SWGS in indoor commercial pools.

[bubblehead]

I did the cup test and only saw a difference of 5 points, 740 vs 735 so it does not seem to be a voltage issue. I also hooked 2 #8 wires to the panel in the equipment room - one to the neutral bar; one to the ground bar and pulled them both out to the pool area and read the following voltages and currents:

gnd to pool water = 250mv dc; 300 mv ac
neut to pool water = 300mv dc; 180mv ac

gnd to ladder or stanchion = 0 to 350mv dc; 180 to 300 mv ac (One ladder read 0vdc)
neut to ladder or stanchion = 0 to 250mv dc; 180 to 215mv ac (One ladder read 0vdc)

I am getting about 150ma dc and 100ma ac on the bonding wire in the equipment room. Also, with all equipment running L3 to the panel had 3.5x the current of L1 or L2 but the voltage was only 2 volts lower L1 or L2.

Anybody see anything wrong with this?

Thanks,

Bubblehead

 

[JasonLion]

I don't like that one ladder read differently. The goal is that everything metal that touches the water should be bonded together, which means that all of the ladders should read the same when compared to a reference point. The voltage differences you saw are small, which suggest that any electrical currents in the water would also be small, but we can't be sure that it is always that way.

To properly test you need to measure resistance from some obvious bonding point in the equipment room to each metal object that touches the water, including pumps, ladders, metal valves, everything. Ideally all of them should be under one ohm. Measuring resistance in the presence of stray currents can occasionally get tricky but normally it is simple enough.

Bonding is often incidentally connected to ground, but there is no requirement that it be connected. That means that small differences between ground and bonding are acceptable. Neutral can move around, depending on how well balanced you loads are and where you connect to it relative to where your loads and the main panel are.

 

[Aquaman95]

Well, ideally the cup test and the probes in the flow cell should be the same but 5 mV is very minor. Frankly just stirring the probes a bit can change the reading so it doesn't appear at that moment you had stray current.

In regards to your other tests I'm going to defer to someone with better knowledge. It could be an intermittent problem as JasonLions said...I'm not really sure...but your problems sound a lot like voltage issues or a bad reference junction in the ORP electrode. I ruled out the reference junction early on because you said you put in new probes and because typically a bad junction will cause a consistently high ORP.

One more question - were the salt cells energized when you did the cup test?