Is Grounding Bushing still required

[Deetz]

We have some new CNC machines that require them to have their own ground rods. So do I still need a grounding bushing and wire in the EMT?

 

[kwired]

Regardless what instructions the manufacturer might have, you can not use a ground rod as a replacement for an equipment grounding conductor.

Grounding bushings are an option (but not the only option) to improve the EGC path when it is weak for various reasons.

 

[infinity]

We have some new CNC machines that require them to have their own ground rods. So do I still need a grounding bushing and wire in the EMT?

Are you using the EMT to feed the machines? If so you may be able to use the EMT as the EGC.

 

[don_resqcapt19]

Why would you need a grounding bushing in the first place?

 

[zbang]

Back up to the original question-
Ignoring the machine's requirement, you need to fulfill all the usual wiring requirements for the branch circuit, including the EGC.

If the mfg requires an additional rod, it's a supplemental grounding electrode, and follows the usual requirements (which indicates grounding bushings for steel EMT, but you may not need physical damage protection at all). At least, that how I read things.

 

[kwired]

Back up to the original question-
Ignoring the machine's requirement, you need to fulfill all the usual wiring requirements for the branch circuit, including the EGC.

If the mfg requires an additional rod, it's a supplemental grounding electrode, and follows the usual requirements (which indicates grounding bushings for steel EMT, but you may not need physical damage protection at all). At least, that how I read things.

Regardless what instructions the manufacturer might have, you can not use a ground rod as a replacement for an equipment grounding conductor.

Grounding bushings are an option (but not the only option) to improve the EGC path when it is weak for various reasons.

to add to what I earlier mentioned - if the EMT in question is only for the electrode conductor then yes you do need to bond the conductor to both ends of any ferrous raceway enclosing that conductor to lessen inductive effects.