If that is Neutral to Ground, then the resistance should be maybe about 0.23 ohms assuming a 100 foot run from the subpanel to the main panel with #10 AWG copper wire.
#10 AWG is 1.1417 Ohms Resistance per 1000 feet.
Electrical issue - Main breaker keeps tripping, Sub panel is not
- Thread starter anomale
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#10 AWG is 1.1417 Ohms Resistance per 1000 feet.
you are right it was hiding. I measured the same from the other hot and all were open hot2-hot, hot2-neutral, hot2-ground
Neutral to ground is the yellow measurement 20 Ohms
If you bought in 1999, then you have had the pool for 25 years.
Since it was resurfaced, that indicates about another 10 to 20 years.
So, 35 to 45 years seems about right.
Also, this type of filter is from the 1970s or 1980s.
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A magnetic trip might be too fast if your monitor only takes periodic samples.
yeah I bought the filter second hand maybe 15 years ago, The house was built in 72 not sure when the pool was installed but at least 30 years,
I'll go grab a new main breaker and see if that improves the impedance.
here is the sample rate, It should have captured a spike if there was one
The Gen 2 samples voltage and measurement channels at approximately 24,000 samples per second. Twice per second, the Gen 2 uses these measurements to calculate root mean square averages for each of the voltage channels, and then intelligently pairs current channels with the correct voltage channel to calculate and report REAL power for each of the 19 CT's in the app.
did some more troubleshooting and the 20 Ohms is coming from the gfci breaker which controls the outlet and lights. I removed that breaker and there is 0 ohms from neutral to ground.
I turned on the main breaker and had that gfci breaker only installed in the sub panel turned on the lights and they worked. Installed the pump breaker and as soon as I flipped it on the pump and main tripped, the gfci did not.
Checked hot to ground and there was a dead short. I removed the pump breaker and measured and still had hot to ground short, removed the gfci and short was gone.
I installed a new outlet and tuened off and on the gfci now there is 20 ohms between the gfci and ground when not installed.
I removed the gfci reset the main and installed the pump breaker and the system has been running fine for the past 15 minutes.
not really sure how GFCI works but it does have a hot and a neutral (spiraled white wire) installed, is it possible that the gfci breaker is internally shorting. What is also weird is that I was seeing a dead short from power to ground and after resetting (on - off - on) the gfci it went to 20 ohms.
I turned on the main breaker and had that gfci breaker only installed in the sub panel turned on the lights and they worked. Installed the pump breaker and as soon as I flipped it on the pump and main tripped, the gfci did not.
Checked hot to ground and there was a dead short. I removed the pump breaker and measured and still had hot to ground short, removed the gfci and short was gone.
I installed a new outlet and tuened off and on the gfci now there is 20 ohms between the gfci and ground when not installed.
I removed the gfci reset the main and installed the pump breaker and the system has been running fine for the past 15 minutes.
not really sure how GFCI works but it does have a hot and a neutral (spiraled white wire) installed, is it possible that the gfci breaker is internally shorting. What is also weird is that I was seeing a dead short from power to ground and after resetting (on - off - on) the gfci it went to 20 ohms.
The timer mechanism looks suspect.
Maybe pull it out and look for burn marks.
When chasing a short to ground, you need to disconnect everything and isolate everything so that you can test each part individually.
Maybe pull it out and look for burn marks.
When chasing a short to ground, you need to disconnect everything and isolate everything so that you can test each part individually.
3 mega ohms with hot wire removed from the breaker measured across gfci hot - neutral
I figured out where the 20 ohms and dead short is coming from. The light switch when off is 20 ohms hot to ground and zero ohms when on which indicates a short in the wiring from the switch to the lights, does that sound right? then the question is why did the lights work when I turned them on if there was a dead short hot to ground and no breakers tripped until I installed the pool pump breaker and turned it on?
I figured out where the 20 ohms and dead short is coming from. The light switch when off is 20 ohms hot to ground and zero ohms when on which indicates a short in the wiring from the switch to the lights, does that sound right? then the question is why did the lights work when I turned them on if there was a dead short hot to ground and no breakers tripped until I installed the pool pump breaker and turned it on?
maybe a faulty switch? I do remember the last time we had the pool lights on about 6 months ago we tripped a breaker. I'll have to do some more testing, on second thought maybe not as it is just switching the hot in and out but the 20 ohms seems weird, I would expect it to be open across the switch when the switch is off and short when the switch is on.
The power wire connects to neutral through the light filament and the neutral ties to ground at the main panel.
You have to disconnect all wires to isolate the individual wires and then test to ground.
Jacuzzi light
black - ground 8 megaohms
white - ground 8 megaohms
white to black - 3 ohms
pool light
black - ground open
white - ground open
black - white 3 ohms
black - ground 8 megaohms
white - ground 8 megaohms
white to black - 3 ohms
pool light
black - ground open
white - ground open
black - white 3 ohms
120 volts at 8 megohms should create a ground current of about 15 μA (microamperes) (0.015 mA (milliamperes)).
ok so bad light or wiring, but why would it still work if there was a short? and in this case why didn't the gfci trip?
thanks for your help by the way, much appreciated
GFCI trips at 4 to 6 milliamps.
Your ground fault is estimated at 15 μA (microamperes) (0.015 mA (milliamperes)).
The light is not causing the main breaker to trip.
The main breaker might be bad or there might be a power short to ground.
Maybe the power to ground is a damaged power wire that is very close to ground but not actually touching.
Only when you have a lot of current does the current jump across the gap with a spark.
It is difficult to try to diagnose an old complex system in person and even more difficult to try to do it remotely.
Sometimes you just have to take things apart and check each thing individually and clean up anything that is suspect.
At 40 years old or older, any part can potentially have corrosion or other issues.
The main breaker might be bad or there might be a power short to ground.
Maybe the power to ground is a damaged power wire that is very close to ground but not actually touching.
Only when you have a lot of current does the current jump across the gap with a spark.
It is difficult to try to diagnose an old complex system in person and even more difficult to try to do it remotely.
Sometimes you just have to take things apart and check each thing individually and clean up anything that is suspect.
At 40 years old or older, any part can potentially have corrosion or other issues.