ptonsparky
Tom
- Occupation
- EC - retired
My problem is the level of voltage they indicate "would not be unheard of" when measured between the equipment and the ground rod that is attached to it. My math using .5 volt as a max allowed, measured from equipment to ground rod with 10' of #6 GEC indicates about 310 amps is flowing on the GEC. I have to agree that there is a problem, but so would a couple tenths of a volt.
Came in an email:
How to Use a Volt Meter for Electrical Safety when working around Electrically Powered Irrigation Equipment.
Caution!!!!!!!!! Before working around any electrical powered irrigation equipment, use a voltmeter to make one of the following two types of checks:
A voltage check measurement from a metal enclosure/metal component to the system?s electrical ground rod is used to determine if the metal enclosure/component is properly bonded and if a dangerous short or fault exists. This measurement should be very close to zero in most cases unless a problem of some type exists although depending on the system, lead length and connections, a couple of tenths of a volt would not be unheard of, but 0.5 volts was the level that became the go-no go reading.
1. Check for voltage between any metal component you will work around (CP sprinklers, drip irrigation filter stations, electric pumps, structural components, etc) and the systems electrical ground rod. Any voltage greater than 0.5 volt measured between a motor, control panel exterior, or structural component to the rod is not normal and could indicate a problem with the electric equipment or wiring. WALK AWAY AND tell the landowner/operator to CALL A QUALIFIED ELECTRICIAN.
A voltage check measurement from metal enclosures/components to ground (earth/soil), is technically a ?neutral to earth voltage? reading and could be different (higher) than the metal enclosure/component to ground rod measurement. This voltage check measurement can be used when the voltmeter leads are not long enough to measure from certain metal enclosures/components to the ground rod, this occurs frequently in the field in many instances. This voltage check measurement includes the contribution of the current flow on the supply utility neutral wire (off site stray voltage) and will fluctuate with current flow on both the utility and on-site neutral wire. In general, anything below 3-5 volts is considered normal. Once a reading goes over 3-5 volts, people can be shocked in wet, damp areas. Around 15 volts is considered a real concern area for humans because that?s where the current starts getting high enough through the resistance of your body to cause involuntary muscle contraction. From a practical safety standpoint, whenever that number is above 5 volts, it is an indication that something in the wiring system (either on or off farm) is not correct and needs attention.
2. If the voltmeters leads are not long enough to measure from the metal component to the ground rod, measure voltage from the metal components to earth (soil), this is commonly called stray voltage. Depending on conditions around the system, a measurement above 5 volts to the earth (soil) could be an indication of a potential problem with the electrical supply system, on-site electrical wiring or equipment. If the check voltage between a metal component and the earth (soil) is above 5 volts, WALK AWAY AND tell the landowner/operator to CALL A QUALIFIED ELECTRICIAN.
If you ever have any doubts about the safety of any electrical powered equipment, WALK AWAY AND ask the land owner or operator to CALL A QUALIFIED ELECTRICIAN.
ALWAYS PLAY IT SAFE!!!!
Came in an email:
How to Use a Volt Meter for Electrical Safety when working around Electrically Powered Irrigation Equipment.
Caution!!!!!!!!! Before working around any electrical powered irrigation equipment, use a voltmeter to make one of the following two types of checks:
A voltage check measurement from a metal enclosure/metal component to the system?s electrical ground rod is used to determine if the metal enclosure/component is properly bonded and if a dangerous short or fault exists. This measurement should be very close to zero in most cases unless a problem of some type exists although depending on the system, lead length and connections, a couple of tenths of a volt would not be unheard of, but 0.5 volts was the level that became the go-no go reading.
1. Check for voltage between any metal component you will work around (CP sprinklers, drip irrigation filter stations, electric pumps, structural components, etc) and the systems electrical ground rod. Any voltage greater than 0.5 volt measured between a motor, control panel exterior, or structural component to the rod is not normal and could indicate a problem with the electric equipment or wiring. WALK AWAY AND tell the landowner/operator to CALL A QUALIFIED ELECTRICIAN.
A voltage check measurement from metal enclosures/components to ground (earth/soil), is technically a ?neutral to earth voltage? reading and could be different (higher) than the metal enclosure/component to ground rod measurement. This voltage check measurement can be used when the voltmeter leads are not long enough to measure from certain metal enclosures/components to the ground rod, this occurs frequently in the field in many instances. This voltage check measurement includes the contribution of the current flow on the supply utility neutral wire (off site stray voltage) and will fluctuate with current flow on both the utility and on-site neutral wire. In general, anything below 3-5 volts is considered normal. Once a reading goes over 3-5 volts, people can be shocked in wet, damp areas. Around 15 volts is considered a real concern area for humans because that?s where the current starts getting high enough through the resistance of your body to cause involuntary muscle contraction. From a practical safety standpoint, whenever that number is above 5 volts, it is an indication that something in the wiring system (either on or off farm) is not correct and needs attention.
2. If the voltmeters leads are not long enough to measure from the metal component to the ground rod, measure voltage from the metal components to earth (soil), this is commonly called stray voltage. Depending on conditions around the system, a measurement above 5 volts to the earth (soil) could be an indication of a potential problem with the electrical supply system, on-site electrical wiring or equipment. If the check voltage between a metal component and the earth (soil) is above 5 volts, WALK AWAY AND tell the landowner/operator to CALL A QUALIFIED ELECTRICIAN.
If you ever have any doubts about the safety of any electrical powered equipment, WALK AWAY AND ask the land owner or operator to CALL A QUALIFIED ELECTRICIAN.
ALWAYS PLAY IT SAFE!!!!