Dale Hayes
Senior Member
From a reference point only, let us consider a wall mount enclosure such as a Hoffman Concept series.
The enclosure is supplied with an integral body grounding stud.
The inner panel is provided with grounding connection points that are stamped with the ground symbol.
A separate grounding bar Sq.D PK15GTA (15 #4-14) and two Sq.D LK100AN (1 #6-2/0) Ground Lug is attached to the panel.
Installed in the enclosure is a 480V 3-phase 500 amp thermal magnetic circuit breaker, control contactors (for switching a heater load) and a 480V to 120V 500VA 1-phase control transformer.
The secondary X2 of the control transformer is wired with a "white" wire for neutral. A green ground wire is also connected between X2 and the grounding bar.
Question: The ground connection from the enclosure door - should it be from the door to the inner panel or from the door to the ground bar?
Also, the 480V, 3-phase wiring does not have a neutral, and there is not a separate 120V 1-phase wiring with a neutral, but there is the 120V neutral created at the Control Transformer X2 power supply and this point is pigtailed across the (-) terminals of the contactor coils.
We don't have a "neutral bar" in this system. When is a neutral bar required?
The enclosure is supplied with an integral body grounding stud.
The inner panel is provided with grounding connection points that are stamped with the ground symbol.
A separate grounding bar Sq.D PK15GTA (15 #4-14) and two Sq.D LK100AN (1 #6-2/0) Ground Lug is attached to the panel.
Installed in the enclosure is a 480V 3-phase 500 amp thermal magnetic circuit breaker, control contactors (for switching a heater load) and a 480V to 120V 500VA 1-phase control transformer.
The secondary X2 of the control transformer is wired with a "white" wire for neutral. A green ground wire is also connected between X2 and the grounding bar.
Question: The ground connection from the enclosure door - should it be from the door to the inner panel or from the door to the ground bar?
Also, the 480V, 3-phase wiring does not have a neutral, and there is not a separate 120V 1-phase wiring with a neutral, but there is the 120V neutral created at the Control Transformer X2 power supply and this point is pigtailed across the (-) terminals of the contactor coils.
We don't have a "neutral bar" in this system. When is a neutral bar required?
