Is it considered a series connection when two or more points are connected from a single grounding branch to different grounding points?

The grounding point is usually the equipotential point or the zero potential point; as long as the grounding resistance and the resistance of the wires meet the requirements, that point can be considered such, and it cannot be regarded as being in series or parallel. My personal understanding.

In the grounding plans I’ve seen before, a connection point was provided on each branch line. In cases where grounding was done first and additional connections were needed later but it was not possible to add more connections, the owner or supervisor would agree to add another connection from one of the branch lines; any further connections had to be made from the nearest grounding bar. An agreement was reached at the time, but no thought was given to the theoretical basis behind it. The only thing that came to mind was that if there was a problem with a branch line (for example, it broke), then the two grounding points on that line would cease to function simultaneously. From this perspective, could it be considered a series connection? But if you consider things from the perspective of points outside the branch lines, one of the lines extending from there malfunctions (for example, it breaks), while the other one still works. From this viewpoint, isn’t this also considered parallel connection? There is another perspective: if a branch can lead to multiple points, can it still be considered a branch?

This sea friend, let me complain about them! First of all, such a grounding bar that extends from the grounding main cannot be called a series connection! To avoid adding additional grounding points to the main grounding conductor, it is essential to conduct a thorough review of the grounding construction drawings, ensuring that each individual device is connected to its own grounding bus bar (such as motor equipment, control panels or button assemblies for on-site starting devices, lighting or power distribution boxes, escalators, and other facilities that require separate grounding) ； At the same time, on-site construction is very crucial; if a grounding bus is used, the grounding wires leading from it must not be connected to the same grounding bolt. The grounding bus must have holes for fixing bolts prepared according to the number of grounding devices it is intended to serve. Furthermore, regarding breakage issues of this type of grounding main, it is usually due to the use of methods such as burying the grounding electrodes deep underground and performing hot welding on the mains. Additionally, anti-corrosion materials are used for these electrodes (such as bare copper stranded wires, copper-clad steel grounding strips, etc.; in environments where corrosion is not a concern, hot-dip galvanized strips are used). The cause of electrode breakage is essentially external mechanical factors, and any damage must be repaired promptly.

Thank you to this teacher for the detailed analysis! I have another question: the material of the grounding branch that branches off from the main grounding wire here is 25x4 galvanized flat iron. Can this be considered a grounding bar? For conventional grounding bars, we take two points from the main grounding conductor (or busbar) and connect them to form a loop that provides redundancy; this can be regarded as creating a small main grounding conductor. From each bolt hole on the grounding bar, another grounding wire is led out to connect to the equipment, which can be considered a separate branch ； For those who have insufficient connection points and are unwilling to expand the grounding bar, it is allowed to use two grounding wires per bolt hole (usually the grounding wires are placed one in front of and one behind the bolt holes in the grounding bar), but no more than that; (it seems this situation is somewhat similar to the topic of discussion again).

This cannot be considered series connection; a series connection is something like A connected to B, B connected to C, and then C connected to the ground bus – that’s what constitutes a series connection. But there’s something wrong with your statement. According to the requirements, all devices must be connected directly to the grounding busbar; calling it a branch circuit isn’t quite correct. This motor doesn’t seem to be part of a complete set of equipment, so it can’t be connected using a grounding bar. But the definition of a busbar branch isn’t very strict either; it should be determined based on the corresponding cross-section. In the case of 25*4, it’s best to run it separately, or you can increase the size of that flat steel and make it part of the busbar, which would also solve the problem.