GFI protecting outdoor floodlights

[JHZR2]

You only THINK they are disconnected. There is a wet path to the normally hot conductor somewhere in the line. Some insulation scrape, some lousy splice, something.

Agree. This is a high resistance ground fault. Seems obvious.

 

[JHZR2]

100k ohms at 120 v should develop about .0012 amps
Not enough current to trip a GFCI .

I was thinking about that too, but what’s to say that the measurement is accurate? And are gfci just made good enough, or can some be “better”?

 

[Pablo]

I was thinking about that too, but what’s to say that the measurement is accurate? And are gfci just made good enough, or can some be “better”?

But dirty water higher resistance leaks might behave a bit differently with a high impedance low current meter than a full 120 VAC

 

[Donald]

So the box under the floodlight is not a single gang box open front and back that is glued to underground conduit. The box continues several inches underground. Maybe a foot or more

I think the box is some kind of outdoor box that you pound into the ground which provides stability for the box and spotlight. Or maybe drop it in a hole and tamp dirt around it. The underground section has openings for UF cable. Probably not conduit.

 

[nomas]

It's a shame you don't live closer . I think I have a Megger out in the garage somewhere . " Here are the key differences between a megger and a multimeter: "

• Functionality: A multimeter measures voltage, current, and resistance, making it versatile for general electrical measurements. A megger, or megohmmeter, specifically measures insulation resistance, which is crucial for testing electrical insulation.
  
  2
• Application: Meggers are used for high-voltage applications and insulation testing, while multimeters are best suited for low-voltage circuit checks.
  
  2
• Accuracy: Generally, the accuracy of a megger is higher than that of a multimeter when it comes to measuring insulation resistance.
  
  1
• Voltage Levels: A megger can apply higher test voltages (250V, 500V, 1000V, etc.) to assess insulation integrity, whereas a multimeter typically operates at lower voltages.
  
  1
• Usage Context: Use a megger for insulation testing in electrical installations, while a multimeter is ideal for troubleshooting and measuring electrical parameters in circuits.
  
  
• 
  
  
  
  
  
  

 

[Pablo]

It's a shame you don't live closer . I think I have a Megger out in the garage somewhere . " Here are the key differences between a megger and a multimeter: "

• Functionality: A multimeter measures voltage, current, and resistance, making it versatile for general electrical measurements. A megger, or megohmmeter, specifically measures insulation resistance, which is crucial for testing electrical insulation.
  
  2
• Application: Meggers are used for high-voltage applications and insulation testing, while multimeters are best suited for low-voltage circuit checks.
  
  2
• Accuracy: Generally, the accuracy of a megger is higher than that of a multimeter when it comes to measuring insulation resistance.
  
  1
• Voltage Levels: A megger can apply higher test voltages (250V, 500V, 1000V, etc.) to assess insulation integrity, whereas a multimeter typically operates at lower voltages.
  
  1
• Usage Context: Use a megger for insulation testing in electrical installations, while a multimeter is ideal for troubleshooting and measuring electrical parameters in circuits.
  https://www.bing.com/ck/a?!&&p=09d7...29tL21lZ29obW1ldGVyLXZzLW11bHRpbWV0ZXIv&ntb=1
• 
  
  
  
  
  

my point exactly above

 

[Donald]

I think this is what I have exactly.

 

[factorytuned2012]

So the box under the floodlight is not a single gang box open front and back that is glued to underground conduit. The box continues several inches underground. Maybe a foot or more

I think the box is some kind of outdoor box that you pound into the ground which provides stability for the box and spotlight. Or maybe drop it in a hole and tamp dirt around it. The underground section has openings for UF cable. Probably not conduit.

Is it a rab post mount kit
https://www.amazon.com/RAB-Lighting...hvlocphy=&hvtargid=pla-4584001418532454&psc=1

 

[Donald]

Is it a rab post mount kit
https://www.amazon.com/RAB-Lighting...hvlocphy=&hvtargid=pla-4584001418532454&psc=1

Similar concept

 

[Donald]

It's a shame you don't live closer . I think I have a Megger out in the garage somewhere . " Here are the key differences between a megger and a multimeter: "

• Functionality: A multimeter measures voltage, current, and resistance, making it versatile for general electrical measurements. A megger, or megohmmeter, specifically measures insulation resistance, which is crucial for testing electrical insulation.
  
  2
• Application: Meggers are used for high-voltage applications and insulation testing, while multimeters are best suited for low-voltage circuit checks.
  
  2
• Accuracy: Generally, the accuracy of a megger is higher than that of a multimeter when it comes to measuring insulation resistance.
  
  1
• Voltage Levels: A megger can apply higher test voltages (250V, 500V, 1000V, etc.) to assess insulation integrity, whereas a multimeter typically operates at lower voltages.
  
  1
• Usage Context: Use a megger for insulation testing in electrical installations, while a multimeter is ideal for troubleshooting and measuring electrical parameters in circuits.
  
  
• 
  
  
  
  
  
  

I have this.

 

[Donald]

It's a shame you don't live closer . I think I have a Megger out in the garage somewhere . " Here are the key differences between a megger and a multimeter: "

• Functionality: A multimeter measures voltage, current, and resistance, making it versatile for general electrical measurements. A megger, or megohmmeter, specifically measures insulation resistance, which is crucial for testing electrical insulation.
  
  2
• Application: Meggers are used for high-voltage applications and insulation testing, while multimeters are best suited for low-voltage circuit checks.
  
  2
• Accuracy: Generally, the accuracy of a megger is higher than that of a multimeter when it comes to measuring insulation resistance.
  
  1
• Voltage Levels: A megger can apply higher test voltages (250V, 500V, 1000V, etc.) to assess insulation integrity, whereas a multimeter typically operates at lower voltages.
  
  1
• Usage Context: Use a megger for insulation testing in electrical installations, while a multimeter is ideal for troubleshooting and measuring electrical parameters in circuits.
  
  
• 
  
  
  
  
  
  

So if my DVM measures 100K won't the megger also read 100K?

One needs a 4 wire ohm meter to read very low, a DVM to read normal resistance and a megger to read very high resistance?

 

[Donald]

Tested using my megger the black to ground and red to ground and both show BAD on the scale. Which is under 20 meg ohms.

 

[factorytuned2012]

Tested using my megger the black to ground and red to ground and both show BAD on the scale. Which is under 20 meg ohms.

Piped not so bad pulling new wires if it’s straight uf no bueńo wait till the fall weather

 

[Donald]

Piped not so bad pulling new wires if it’s straight uf no bueńo wait till the fall weather

So the way things were installed. The post is in the ground. The wires come up through a opening in the bottom of the post. The post was buried pretty low in the ground and over the years with lawnmowers and weed whackers the covers got beat up. Certainly possible water got into the inside of the post and some could have dropped into the UV cable where the outside sheathing is cut away to expose the wires.

I wonder if that is enough.

Seems odd that both the red and black wire have same resistance to ground. If the UV cable was damaged I might expect one wire to have low resistance to ground but not both red and black.