Single Phase Grounded

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electrics

Senior Member
Hi chaps! I want to learn why do we need to ground one of the three phases in TN-S systems,İf I am not wrong it has to do with the lack of a neutral point and so it aims to create a neutral point true? İt says in the book of wolfgang Hofheinz "electrical safety in medical places" that it (phase conductor) is grounded if there is no neutral point or you cant find it , so how can it be that you ground a phase if it has one and you ground one phase since you cant find? I think it is illogical to ground a phase conductor in a TN-S system from a second point except the neutral point if there is one. What makes me confused is the word "find" here?
I cant find a neutral so I do ground a phase . İs this logical since overcurrent device is suppsed to operate in this case automatically.
 

Smart $

Esteemed Member
Location
Ohio
First question is what code are you installing under? TN-S is IEC grounding terminology. In such a grounded system, PE and N are separate conductors except they are connected together and also earthed near the source. This is a typical 3? 4-wire grounded system under the NEC.

Just exactly where have you looked for the neutral?

I'd have a hard time considering any book as authoritative if it told me to ground a phase if I can't "find" a neutral.

Need more facts and less fiction...
 

Smart $

Esteemed Member
Location
Ohio
how can a main bond jumper be "Screw"?
The most common situation is many panelboards have a grounding busbar attached to the enclosure while the neutral busbar is isolated (by insulating barrier or air space). Manufacturers typically provided an aligned hole in the neutral busbar, insulating barrier, and enclosure, where the latter is threaded. Installing the manufacturer provided screw bonds the grounding conductor and system with the grounded conductor.
 
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