Grounding Systems

New!

Intermediate

Video/Text

Video/Text

Boat Electrics

4 Lessons

0% Not started

In the lessons of this brief overview module, we separate out the different components of a grounding system and investigate its core installation requirements. A proper grounding system is vital for the safety of AC and DC systems, corrosion prevention, and lightning protection.

Grounding Systems

New!

A short introduction to the various grounding circuits we will cover in this overview module.

Video lesson

New!

In this lesson, we take a look at the common ground point, which we call a grounding bus to distinguish it from what we have called the DC circuit ground. We also learn about the core differences between grounded and isolated ground DC systems.

Video lesson

New!

We learn about the purpose of all grounding systems plus installation requirements for grounding and bonding systems depending on this purpose.

Video lesson

New!

Text lesson

Follow

About the teacher

Jan & Nigel

This course has been created in a joint effort by Nigel Calder and Dr. Jan Athenstädt. Nigel is responsible for the lecture notes and Jan will take the role of presenter and guide you through the lessons.

  • There was one question about the combining of grounding wires. In the video, the information given was that all of them can be combined (including AC), but in most cases they are not, but in most cases AC is done separately (because of the 3 core cable). The answer marked as correct states that AC is ALWAYS done separately.

    • Hi Michal,
      Thanks for your comment. I am not sure which part of the video you mean, but I assume it’s the sentence “In theory, its function could be combined with any of the other grounding conductors. But in practice it is always run as a separate conductor, in a common sheath with the hot and neutral current carrying conductors.”?
      I think this sentence might not be as clear as it should have been. While this would work in theory, the standards require that the AC conductor is run in a common sheath. We will clarify this in the next revision of the video.
      Best
      Jan

  • First of all: thank you so much for the course!
    I am a complete novice: high-school physics 45 years ago.

    On my boat the main isolation switch is on the NEGATIVE conductors from the batteries (2001 Bavaria 40 cruiser). This seems unusual. There is no isolation switch on the positive conductors from the batteries.

    If the negative bus-bar was connected to ground then there surely would be a short from positive battery terminals to ground?

    I am wondering if this means that the boat has an isolated DC system rather than a grounded system?

    I would be interested in your thoughts.

    • Murray,

      I believe (but am not certain) Bavaria boats from this era were wired with the battery isolation switch in the negative side of the circuit. In normal circumstances, in a sense it doesn’t matter which side of the circuit the switch is in so long as it truly isolates the batteries. But for decades the ABYC and ISO have settled on negatively-grounded systems having the isolation switch in the positive side of the circuit.

      With your negative side switch, even if the negative side of the boat downstream of the isolation switch is connected to ground it will not create a short circuit to the positive side. For this to happen, there needs to be a short from the positive side to something that is grounded.

      Another installation that is commonly seen (many French-built boats) is a battery isolation switch in both the negative and positive sides.

      There are strongly held opinions in favor of both negative side switching, and switching both conductors. If yours is the original factory installation and not some later owner modification, I would leave it alone. If you want to comply with the current ABYC and ISO standards, I would move it to the positive side, or add a positive side switch.

      Nigel

  • {"email":"Email address invalid","url":"Website address invalid","required":"Required field missing"}
    >