Equipment ground vs cable ground

[AmazingTrans]

Hi there, i have been in practice to provide equipment ground based on the largest load on the equipment. I was never explained what was the NEC / standard justification of providing equipment ground. Today, most of my motor load runs in cable and they have ground wire that comes with the motors cables. This ground is either tie to the source ground, or tie into VFD drive ground point which I am going to guess it also tie to the source ground.

So, will i still need to provide equipment ground? If yes, what standard is this referring to?

Equipment ground = ground that ties the equipment to the source power ground.

If i remember correctly, in the past not many people uses cable that has ground wire that comes with it. And many users pull their own 480V to terminal blocks and a separate ground to the equipment. And this ground has to be able to handle 1 fault path and that the the largest load fault.

Hope to hear from someone. Thanks!

AmazingTrans.

 

[don_resqcapt19]

If you are using cable, the NEC requires that the equipment grounding conductor be in that cable.

 

[AmazingTrans]

If you are using cable, the NEC requires that the equipment grounding conductor be in that cable.

What i have is my motor is mounted on the machine with the bare surface of the motor touching the surface of the machine.
The cable is mounted into the motor pecker head. And also assuming the ground bar in the pecker head is also grounded throughout the motor housing.

Is the EGC in cable would be sufficient for the machine body ?

Thanks

 

[ActionDave]

What i have is my motor is mounted on the machine with the bare surface of the motor touching the surface of the machine.
The cable is mounted into the motor pecker head. And also assuming the ground bar in the pecker head is also grounded throughout the motor housing.

Is the EGC in cable would be sufficient for the machine body ?

Thanks

Most likely yes. What is the reason for your concern? The size of an equipment grounding conductor conductor is not based on the size of the metal structure it is tied to, it is based on the overcurrent protection size.

 

[AmazingTrans]

Most likely yes. What is the reason for your concern? The size of an equipment grounding conductor conductor is not based on the size of the metal structure it is tied to, it is based on the overcurrent protection size.

I guess, recently I have been using cables instead of wires.
With wires in conduits, we pull one ground wire that is based off the largest load and tie to the machine surface. So that, if someone pull out the live exposed wires and accidentally touched the equipment, it will at least trip the overcurrent device by flowing back to this ground wire.

Since, most of the devices are on cables that comes with ground wire now, i'm guessing i can eliminate that EGC.

Does anyone know what article in the NEC specify the grounding in the cable?

 

[ActionDave]

I guess, recently I have been using cables instead of wires.
With wires in conduits, we pull one ground wire that is based off the largest load and tie to the machine surface. So that, if someone pull out the live exposed wires and accidentally touched the equipment, it will at least trip the overcurrent device by flowing back to this ground wire.

The same thing happens with any properly sized EGC.

Since, most of the devices are on cables that comes with ground wire now, i'm guessing i can eliminate that EGC.

I have no idea what this means. Are you saying you have abandoned existing conduit feeds?

Does anyone know what article in the NEC specify the grounding in the cable?

250.122 and Table 250.122.

 

[AmazingTrans]

The same thing happens with any properly sized EGC.


I have no idea what this means. Are you saying you have abandoned existing conduit feeds?


250.122 and Table 250.122.

It looks something like this:


In the past we have many wires with a single ground that is ran through a flex conduit.
Today, we utilized cables as such: http://www.lappusa.com/canada/Spec_Template.asp?nGroupID=10140

 

[petersonra]

regardless of how you do it the EGC for the branch circuit that supplies the motor has to have an EGC run with it. It can be the metal conduit that the conductors are run in, or a wire in the conduit, or a wire in a cable. But it has to be run with the circuit conductors. if the circuit conductors are a cable, the cable has to include a properly sized egc.

eta: you can run a cable thru existing conduit if you like but you still have to run an EGC in the cable, if that is what you are asking about.

 

[don_resqcapt19]

I guess, recently I have been using cables instead of wires.
With wires in conduits, we pull one ground wire that is based off the largest load and tie to the machine surface. So that, if someone pull out the live exposed wires and accidentally touched the equipment, it will at least trip the overcurrent device by flowing back to this ground wire.

Since, most of the devices are on cables that comes with ground wire now, i'm guessing i can eliminate that EGC.

Does anyone know what article in the NEC specify the grounding in the cable?

Take a look at 300.3(B).

(B) Conductors of the Same Circuit. All conductors of the same circuit and, where used, the grounded conductor and all
equipment grounding conductors and bonding conductors shall be contained within the same raceway, auxiliary gutter, cable tray, cablebus assembly, trench, cable, or cord, unless otherwise permitted in accordance with 300.3(B)(1)through (B)(4).

 

[joshuastewart32]

Sent from my iPhone using Tapatalk