6 of 7 Grounding Myths (26min:55sec)

Summary

This video addresses common myths and misconceptions related to electrical grounding and bonding, highlighting dangerous practices that can lead to unsafe conditions. The speaker discusses improper lightning protection, unnecessary grounding of light poles, and misconceptions about grounding generators and welding equipment. By debunking these myths, the speaker emphasizes the importance of following proper guidelines like the National Electrical Code (NEC) for safe electrical practices, warning against relying on outdated or incorrect information. The overall message stresses informed decision-making to prevent electrical hazards and ensure safety.

Takeaways

• 😀 Grounding an array does not protect against lightning; proper lightning protection involves specific measures and not just grounding the structure.
• 😀 Grounding light poles is not necessary or required by the NEC; existing metal structures already provide grounding through their foundation.
• 😀 Multiple ground rods around a light pole or generator won't reduce the risk of electrical hazards from lightning or other electrical faults.
• 😀 The idea that more grounding equals more safety is a misconception; it's not always the best approach to add extra ground rods or electrodes.
• 😀 Generators should be grounded according to NEC standards, not necessarily with additional ground rods as suggested in older instructions from manufacturers.
• 😀 Bonding components together does not eliminate the risk of voltage differences; incorrect grounding and bonding can still lead to dangerous electrical hazards.
• 😀 Step potential, or voltage differences between points on the ground, cannot be minimized just by adding more grounding devices.
• 😀 Attaching ground rods to equipment or metal structures does not guarantee safety from voltage rise or step potential hazards.
• 😀 Grounding misconceptions can lead to dangerous electrical conditions, such as stray currents in a building or electrical systems when equipment is improperly grounded.
• 😀 In welding, the 'ground lead' is not for connecting to the ground but for returning current to the welding machine; improper grounding in welding systems can lead to dangerous electrical issues.

Q & A

Why is grounding a light pole not necessary or required by the NEC?

Grounding a light pole is not required by the NEC because simply installing a ground rod at the base of the pole does not protect the equipment at the top. Grounding should be done to prevent dangerous voltage rises, but a single ground rod does not offer effective protection against lightning or other electrical hazards.

What is the misconception about grounding generators, and what does the NEC say?

The misconception is that grounding a generator requires additional ground rods or specific grounding techniques. However, the NEC simply requires that a generator be grounded properly according to its guidelines. Manufacturers’ instructions, like those from Generrack, may previously have been misleading, but now they align with NEC standards.

What is the problem with adding multiple grounding electrodes to reduce hazards?

Adding multiple grounding electrodes does not necessarily reduce the voltage rise or danger from step potential. In fact, it can create more hazardous situations by providing more paths for electricity to travel, which may lead to more risks, including electrical shock or fire.

What does the speaker say about bonding devices together to eliminate voltage differences?

The speaker argues that bonding devices together does not eliminate voltage differences, especially if the devices are connected to the ground. Bonding only ensures that parts are electrically connected, but it does not remove the voltage from the system, which can still pose a danger.

Why does the speaker say that grounding does not minimize the hazard or reduce voltage rise?

Grounding does not minimize the hazard or reduce voltage rise because grounding electrodes do not always provide a low-resistance path to ground. This can lead to dangerous voltage gradients, particularly in wet or conductive environments, which grounding alone cannot resolve.

What is the importance of grounding according to NEC when it comes to equipment like generators?

The importance of grounding equipment like generators according to NEC is to ensure safety and prevent electrical hazards. Proper grounding helps protect both the equipment and individuals from electrical shock or fire, but it should be done as per NEC standards, not based on outdated or incorrect manufacturer instructions.

What role does step potential play in grounding systems, and why is it a concern?

Step potential refers to the voltage difference between the ground and the surrounding area that can occur when electrical current travels through the ground. It is a concern because it can cause dangerous shocks, especially when someone is standing in an area with different electrical potentials. Simply grounding multiple points does not address this issue effectively.

How does the speaker challenge the idea of grounding more to improve safety?

The speaker challenges this idea by pointing out that simply adding more grounding rods or electrodes will not reduce the hazard. In fact, it may spread the hazard to more locations, increasing the risk of electrical accidents rather than reducing them.

What is the misconception about the ground lead in welding machines, and why is it dangerous?

The misconception is that the 'ground lead' in welding machines should be connected to an external ground. However, in welding, the ground lead is meant to connect to the workpiece to complete the circuit. Connecting it to an external ground creates an unintended path for current, which can lead to dangerous situations like fires or shocks.

What is the potential danger of grounding in a fiberglass boat, and how does it relate to electrical hazards?

In a fiberglass boat, bonding metal parts together can create dangerous conditions if an electrical fault occurs, such as when a shore power connection is miswired. In this case, the boat's metal parts can become energized, and someone standing in the boat could be electrocuted due to the electrical current flowing through the water, especially in freshwater.