Driven ground at each machine

[Minuteman]

Brian, I hear you, but he only said that:

it is customary for each unit to have a driven ground rod.

Also, the Plant Engineer doesn't want it. However, I would be glad to install them, as long as it is understood that I am not responsible for anything under the slab that might be damaged by me driving the rods.

But hey, sign me a change order, I can use the money.

 

[Minuteman]

Thought I would include some pics.

 

[boboelectric]

WRONG, Like the isolated grounds they made us put in ,a separate rod.

 

[George Stolz]

He notices that I am installing a EGC in each conduit (per local amendment) and says that it is customary for each unit to have a driven ground rod.

The way you said this, it almost sounds as though he didn't want the EGC - perhaps not an EGC at all - and if my paranoia is anywhere close to the truth, that rep scares me.

 

[Minuteman]

George, that was my impression as well. Kinda like he didn't want the EGC. He is comin' back Thursday to "fire up" (his words) the Air Compressors.

I love these customs :grin:. Since I'm a rabble rouser, I'd ask him when he's taking you to lunch, since 'round here, the mfg's rep always takes the electricians to lunch after the installation. Save some pie for me .

I'm gonna show up for more than lunch and pie. I wanna know more about this dude's notions on grounding.

 

[FNCnca]

I know of a large CNC machine manufacturer that will NOT startup a new machine if it has an EGC attached. They require rods only. They will claim that having an EGC will void your warranty. Service techs will cut the EGC before turning on the power for the first time.
I do not know what their problem is with an EGC, but they do not want them.

Unfortunately, the company I worked, for did not see this as a problem, so it was done per the manufacturers specs. The minute their field techs left the building, we hooked up the EGCs.

How common this is, I don?t know, but it does happen.

I have not dealt with this machine manufacturer in 10 years, so I do not know if this is still their practice.

 

[Minuteman]

This is from the local supplement to the 2002 NEC

250.118 is hereby deleted and the following language is substituted:

All raceways or cable assemblies shall include a green or bare equipment grounding conductor. Said conductor shall be bonded to all non current carrying metal parts of the electrical system.

So, he best not be cuttin' my green wire!

 

[masterelect1]

They want them for lightning purposes...come on where have you guys been... I know you were absent for that class..probably driving ground rods that day and you were too tired for class.

Are you serious or is this tongue in cheek-- If he wants a lightning arrestor system then he needs to reference NFPA 780.

The last thing I would want in life is to be operating the machine that takes the full brunt of a lightning strike because the facility has no LPS in place>