Grounding Bonding Flashcards
What is bonding in hazmat operations?
Bonding connects all metal objects (like the tanker, pump, and barrels) with cables to equalize electrical charges and prevent sparks.
What is grounding in hazmat operations?
Grounding provides a safe path for static electricity to flow into the earth to prevent static buildup and sparks.
What is the Fall-of-Potential method?
It’s a method to measure ground resistance by introducing current into the ground and calculating the voltage drop.
One of the first considerations when grounding/bonding
Identify what?
Identify where to place the grounding rod, bonding cables, and probes.
What is the first step in bonding equipment?
Attach a bonding cable to the damaged vessel, ideally on bare metal for contact
How do you connect the pump to the tanker?
Bonding cable bare metal to bare metal
Tank first
How do you bond the barrels to the system?
Use another bonding cable to connect the pump to the barrels, usually by placing a grounding rod in the barrel itself
Where do you place the grounding rod?
Drive it into soft or moist soil, 10-20 feet from the tanker.
How do you connect the grounding rod to the bonded system?
Attach a grounding cable from the rod to the tanker or pump.
Object first then rod
How far should the current probe (H) be from the grounding rod?
Place it about 50-80 feet away.
Where do you place the potential probe (S)?
At 62% of the distance between the grounding rod and the current probe.
30-45 if 50-80
What does the E terminal on the AEMC 6422 connect to?
The grounding rod, which is the rod placed near the tanker or operation site.
What does the H terminal on the AEMC 6422 connect to?
The current probe, placed approximately 50-80 feet away from the grounding rod.
What does the S terminal on the AEMC 6422 connect to?
The potential probe, placed 62% of the distance between the grounding rod and the current probe.
What is the acceptable ground resistance for general grounding systems?
25 ohms or less, per the National Electrical Code (NEC).
1000 or less for NFPA (jfrd uses this)
What do you do if the AEMC 6422 shows resistance above 1000 ohms
Drive the grounding rod deeper, move it to wetter soil, or add a second rod 6-10 feet away (Atleast 2x the distance of the depth of the rod)
What tool should you use to drill into a tanker?
A pneumatic (air-powered) drill to avoid sparks.
How do you prevent sparks when drilling the tanker?
Bond the drill to the tanker with a bonding cable.
What type of wires are included in the AEMC 6422 kit for grounding and bonding?
Stainless steel
Why are the test leads in the AEMC 6422 kit made of stainless steel?
Stainless steel is used because it resists corrosion, can handle rough conditions, and provides reliable conductivity for testing in various environments.
What material are the grounding rods in the AEMC 6422 kit made of?
The grounding rods in the kit are typically copper-clad steel, combining the conductivity of copper with the strength and cost-effectiveness of steel.
Why are the rods in the AEMC kit copper-clad instead of solid stainless steel or copper?
Copper-clad steel rods are more conductive than stainless steel and stronger than solid copper, making them ideal for accurate ground resistance testing.
How do stainless steel wires in the AEMC kit contribute to testing accuracy?
Stainless steel provides consistent electrical flow, ensuring accurate measurements, while withstanding harsh environments without degrading.
Why are the test lead clamps in the AEMC kit made from corrosion-resistant metals?
Corrosion-resistant clamps ensure long-term durability and maintain strong, reliable electrical connections during tests.
Why are stainless steel wires paired with copper-clad rods in the AEMC 6422 system?
Stainless steel wires are durable and resistant to environmental damage, while copper-clad rods provide superior conductivity for accurate grounding.
Why is it important to have bare metal contact with the AEMC clamps?
Stainless steel wires and clamps must connect to bare metal surfaces to avoid resistance from coatings, rust, or debris.
What is the 52/62/72 rule in Fall-of-Potential testing?
The rule involves taking measurements with the potential probe at 52%, 62%, and 72% of the distance between the grounding rod and the current probe to ensure accuracy.
Why is the 62% point the standard for Fall-of-Potential testing?
At 62% of the distance between the grounding rod and the current probe, the ground resistance reading reflects the true resistance of the grounding system.
What does the 52% and 72% test in the 52/62/72 rule accomplish?
Testing at 52% and 72% ensures that the measurements are consistent and not influenced by interference from the current probe.
What does triangulating a field mean in Fall-of-Potential testing?
Triangulating a field involves testing at multiple distances and directions to confirm the reliability of ground resistance readings and detect possible interference.
Why is triangulating a field important in grounding tests?
It ensures accurate measurements by identifying any anomalies or interference that could distort the resistance reading.
What is an ohm?
An ohm is the unit of measurement for electrical resistance, representing how much a material resists the flow of current.
What is potential?
Potential, or voltage, is the difference in electrical energy between two points, which drives the flow of current.
What is current?
Current is the flow of electric charge, measured in amperes (amps), which moves through a conductor.
What is resistance?
Resistance is the opposition to the flow of electrical current, measured in ohms.
What is conductivity?
Conductivity is the ability of a material to allow electric current to pass through it easily.
What is static electricity?
Static electricity is the buildup of electric charge on the surface of an object, which can discharge as a spark.
What is a grounding system?
A grounding system is a setup that provides a safe path for electrical current to flow into the earth, preventing buildup and sparks.
What is a voltage drop?
A voltage drop is the decrease in electrical potential as current flows through a resistance.
What is a circuit?
A circuit is a closed loop through which electrical current flows.
What is the purpose of a grounding rod in electrical systems?
A grounding rod dissipates electrical energy into the earth.
What is electrical potential difference?
Electrical potential difference is the energy difference per charge between two points, causing current to flow.
The ______________ rod is driven into the ground near the tanker to provide a path for static electricity to flow into the earth.
grounding
The ______________ cable connects the tanker, pump, and barrels to equalize their electrical charges.
bonding
The ______________ probe is placed approximately 50-80 feet away from the grounding rod.
current
The ______________ probe is placed at 62% of the distance between the grounding rod and the current probe.
potential
The ______________ terminal on the AEMC 6422 is connected to the grounding rod during testing.
E
The ______________ terminal on the AEMC 6422 is connected to the current probe during testing.
H
The ______________ terminal on the AEMC 6422 is connected to the potential probe during testing.
S
The AEMC 6422 measures ______________ to determine if the grounding system is effective.
resistance
During Fall-of-Potential testing, the AEMC 6422 calculates resistance using the relationship ______________ = Voltage ÷ Current.
Resistance (Ohm’s Law)
If the measured resistance is greater than ______________ ohms, the grounding rod may need to be driven deeper or moved to a better location.
1000
The ______________ rule involves placing the potential probe at 52%, 62%, and 72% of the distance from the grounding rod to the current probe.
52/62/72
Consistent readings at 52%, 62%, and 72% confirm there is no interference, meaning the ______________ is accurate.
ground resistance
If resistance is too high, adding another grounding rod ______________ feet away and connecting it to the first rod can improve the system.
6-10
(Double the depth of the rod)
______________ is the flow of electric charge through a conductor, measured in amperes.
Current
______________ is the opposition to the flow of current, measured in ohms.
Resistance
______________ is the energy difference between two points that drives the flow of current, measured in volts.
Potential (or Voltage)
A ______________ is a closed loop through which current flows.
circuit
Static electricity is a buildup of ______________ charges on an object, which can discharge as a spark.
electric
The ______________ measures how much energy is lost as current flows through resistance.
voltage drop
A ______________ system provides a safe path for stray current to flow into the earth.
grounding
Considerations
• Locate _______ points on the tankers and transfer pump.
• Make connections to damaged tanker first to avoid a ______
• When possible, grounding systems should be established _____and outside of the ____
• Resistance measurement should be compliant with your local jurisdiction which usual follows _________ less or NEC _______ lower is always better. Higher resistance means longer ______ time.
Grounding
Spark
Up hill hot zone
NFPA 472/1000 ohms
At 1000 ohms or less
Static discharge
