Groundin Myths

Status
Not open for further replies.
W

woofy

Member
Well I got Mike's grounding and bonding newsletter and it did just what it was supposed to do. Got me scratching my head.
Here's the one that got me.

Ground rods are not required at a separate building supplied by a 60 ampere 4 wire feeder (120/240 V -, 2 hots, neutral and ground, with the neutral floated at the separate building disconnect).
True or False.....Well it's false

I put ground rods at each building and bond them to the grounding bar in the panel at each out building. Just for the lighning to have a good path to ground and save some equipment hopefully.
Not to clear a ground fault.

May be I'm not saying this correctly. :(
Be gentle....Mike :D
 
Re: Groundin Myths

That is correct as a feeder is not a branch circuit that could be called a single circuit in which a grounding electrode would not be required if a EGC is ran with the circuit conductors. which if the 60 amp 4-wire cable fed a load and not a panel board with OCPD's in it. it would be called a single circuit.
 
Re: Groundin Myths

woofy,
The question contains the word "not" and when combined with the answer "false" means that ground rods are required at the second building.
Don
 
Re: Groundin Myths

I'm really trying to get this. Maybe I'm trying to hard. ok here goes

outbuildings... should be effectivly grounded 250.32(A) Exception noted OK

Bonded 250.32(B) OK

(1)EGC shall be run OK

(2) Where EGC is not run after reading sentence 2&3
I conclude that the Grounded conductor SHALL be used for the bonding of equipment.

Am I reading this right.
250.32(B)(1) Is the preferred method, if nothing else is available use 250.32(B)(2)(3)
also am I correct in thinking that in this instance bonding the GC to the eqipment is correct

wwhheewww......Mike
 
Re: Groundin Myths

Hi Mike

I will divide your questions into two separate issues.

1)Electrodes

All buildings or structures supplied by a feeder or service must have grounding electrodes.

The electrodes will always be connected to the grounding conductors in the building or structure.

2) 250.32(B)(1) and 250.32(B)(2)

As far as the NEC is concerned there is no preferred method.

Either method is as good as the other if installed and maintained correctly. Each has advantages and disadvantages.

250.32(B)(1) If you choose this method the grounded conductor and the grounding conductor will be kept separate at the remote panel and the electrode will connect only to the grounding conductor.

250.32(B)(2) We are free to choose this method as long as we follow the rules in this section.

In this case no EGC is run to the remote panel, the grounded conductor is bonded to the enclosure and connected to the electrodes.

This method is no different than a service, the grounded conductor serves a dual purpose.

Back to which method is preferred, well that depends on who you ask and the specifics of the job at hand. :D I like that the code gives us choices on this. A long feeder to a remote building is a good candidate for 250.32(B)(2)
 
Re: Groundin Myths

Thanks Bob
I don't live at the end of the earth but I can see it from here. I live in a rural ranching community and it's a 120 miles to the nearest large town. I think that this is the kind of stuff you would talk about in the shop at the end of the day or before you go out. I really like this forum because it allows me to do what others take for granted, ask questions. the only time I get to talk to other guys is at CE classes or if they happen to come to town.

As it happend I had a good grasp of this "the way I've alway done it" was correct. Mostly I think the code is common sense if you will take the time to step back and look at it and think about it.

an old timer told me this about grounding. If you don't have you're equipment grounded and there's a "short" somewhere you're gonna take the whole load, and that'll kill ya. He's the one in this country that really got ranchers to thinking about having eqipment grounded.
Well I got kind of windy But thanks for you're time. I really enjoy this forum

thanks........Mike
 
Re: Groundin Myths

Mike's quiz was a real brain teaser meaning it got me thinking about several things.

Alot of the people who responded to the quiz found it very useful to them, but most asked for follow-up comments to each question(by mike or somebody that understands his way of thinking). This helps when you pass the quiz along to a classroom, or fellow electricians.

The quiz could spark many an intelligent debate, on jobsites everywhere,but if you don't have reasons for Mikes "all false" answers, it could lead to further confusion.

does anybody know if he's planning on replying to his quiz?

Thanks in advance, Stevie P
 
Status
Not open for further replies.
Top