Lots of sparks

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ptonsparky

ptonsparky

Tom
Location
NE (9.06 miles @5.9 Degrees from Winged Horses)
Occupation
EC - retired
I was called yesterday to replace a starter in a bucket on a MCC. After I was there a few minutes I began to see why I was called in. The night crew was not around to question so I don't know the sequence of events.

To make it short, after the fault they had numerous small smoldering fires caused by the arcing and sparking of the raceways in the area of the MCC. Dust is present but it is not considered hazardous. The fault was in a bucket of the MCC. (blew out the side of a 15 amp MCP and tripped the main.) 480/277 and is not supposed to have any neutral load. I do know the grounded conductor, neutral, for this underground service was "added" and is not in the same raceways as the SE conductors. Most likely undersized.

Operators had mentioned seeing sparks along various metal contact points in the past, at times of faults.

The only way I can see this happening is if the the grounded conductor to this service entrance equipment is broken entirely and current is trying to find a path via raceways, and equipment to one of the other services. Could this be a result of the undersized separated neutral?
 
76nemo

76nemo

Senior Member
Location
Ogdensburg, NY
Does this post not support the pull of an EGC:confused: Okay, some rely on the raceway, some argue with me that the added pull is a waste of money, I say it is bologna. Now you'll pound me with a finacial sense, and try to make me look stupid. I don't care what code allows or permits, pull an EGC:mad:

Round #1, brad goes down.
 
iwire

iwire

Moderator
Staff member
Location
Massachusetts
76nemo said:
Does this post not support the pull of an EGC:confused: Okay, some rely on the raceway, some argue with me that the added pull is a waste of money, I say it is bologna. Now you'll pound me with a finacial sense, and try to make me look stupid. I don't care what code allows or permits, pull an EGC:mad:

Round #1, brad goes down.
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As long as it's your money your spending all is good. :cool:

When it's coming out of my bonus and

  • specs do not require it
  • the NEC code cycle after code cycle says conduit is effective
  • and the fact remains that a properly installed steel conduit has a lower impedance then the copper EGC inside it

I will not automatically install an EGC. :smile:
 
brian john

brian john

Senior Member
Location
Leesburg, VA
Iwire:

Based upon the fact that the GFP was disabled contributes to the delay in operation of the main, not necessarily the lack of a copper EGC. So a properly installed system....and the copper EGC is as noted

When it's coming out of my bonus and

specs do not require it

the NEC code cycle after code cycle says conduit is effective

and the fact remains that a properly installed steel conduit has a lower impedance then the copper EGC inside it
Click to expand...
 
76nemo

76nemo

Senior Member
Location
Ogdensburg, NY
iwire said:
As long as it's your money your spending all is good. :cool:

When it's coming out of my bonus and

  • specs do not require it
  • the NEC code cycle after code cycle says conduit is effective
  • and the fact remains that a properly installed steel conduit has a lower impedance then the copper EGC inside it

I will not automatically install an EGC. :smile:
Click to expand...


Bob, I would like for your you to do the work on my new shop, then I would have no worries. If your neighbor Mary gets the bid, or her next door Joey the painter, I am paying Bob the higher bid. Bob, I like you alot, but don't feed me that crap about raceway supporting grounding issues. You are a smarter man than me, but I won't support that statement or the NEC for that matter. Lower impedance, sure. You are darned right there. Bobby comes through with a fork lift extended and breaks your pretty looking EMT run. Your ground path is gone. Don't gripe about Bobby, he knows nothing about electrical work. We're getting petty here, but we have a point.
 
H

hillbilly1

Senior Member
Location
North Georgia mountains
Occupation
Owner/electrical contractor
Added neutrals to similar type service, the plant was burning up 250 hp refrigeration compressors, and the EE decided it was the equipment ground/neutral was too small, pulled out the # 4 that was in there since Sherman burned Atlanta, and pulled in 3/0, The original contractor did not have the gear bonded to the building steel or cold water, corrected that also. Assumed that fixed it, have not heard any more about it in over a year.
 
iwire

iwire

Moderator
Staff member
Location
Massachusetts
76nemo said:
Bob, I like you alot, but don't feed me that crap about raceway supporting grounding issues.
Click to expand...

First Please remember our PMs.

Second I am not feeding you anything but truth.


Bobby comes through with a fork lift extended and breaks your pretty looking EMT run. Your ground path is gone.
Click to expand...

Sounds like a bad place to run an EMT.

You want to run an EGC fine as long as that is cool with the person paying the bill life is beautiful. :cool:

The facts remain

The NEC does not require it and continues to reject proposals asking for it due to lack of proof it is needed.

Properly installed conduit does have a lower impedance path then the copper EGC inside typically pulled inside.

(Did you know the the CMP considers the steel conduit used in redundant grounding of patient care area circuits as the primary grounding means?)

As I said do what you want, but maybe research it instead of just going by your gut instinct. :smile:

Take Chicago, very tough local electrical code, all pipe required, few wire EGCs. I bet there is no trail of death and destruction because of that.
 
brian john

brian john

Senior Member
Location
Leesburg, VA
Bobby comes through with a fork lift extended and breaks your pretty looking EMT run. Your ground path is gone. Don't gripe about Bobby, he knows nothing about electrical work.
Click to expand...

Joey does tighten the ground screw.
Homer runs a fork lift into the busway with copper EGC.

I am all for installing copper EGCS but you cannot account for the actions of what may happen.
 
76nemo

76nemo

Senior Member
Location
Ogdensburg, NY
iwire said:
First Please remember our PMs.

Second I am not feeding you anything but truth.




Sounds like a bad place to run an EMT.

You want to run an EGC fine as long as that is cool with the person paying the bill life is beautiful. :cool:

The facts remain

The NEC does not require it and continues to reject proposals asking for it due to lack of proof it is needed.

Properly installed conduit does have a lower impedance path then the copper EGC inside typically pulled inside.

(Did you know the the CMP considers the steel conduit used in redundant grounding of patient care area circuits as the primary grounding means?)

As I said do what you want, but maybe research it instead of just going by your gut instinct. :smile:

Take Chicago, very tough local electrical code, all pipe required, few wire EGCs. I bet there is no trail of death and destruction because of that.
Click to expand...


Why is it that when I think I am dead on, this guy, (Bob), throws me off 30 degrees? The NEC states rules for legit installers/contractors, they know/consider NOTHING for hacks. They care about nothing except the initial install. That's what I am getting to.
 
brian john

brian john

Senior Member
Location
Leesburg, VA
hillbilly:

That was a mess to clean up/repair.

76nemo

Because Bob uses LOGIC? Heck I do not know, he's got a way about him.

There are other items that are not taken into account (?), most structures have multiple fault paths in addition to the EMT path, rebar, building steel, drop ceilings, metallic piping systems, ducts. ECT. These obviously are hard to account for as they will vary from building to building.
 
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76nemo

76nemo

Senior Member
Location
Ogdensburg, NY
Shoot....

Shoot....

I apologize to Bob again and the forum about using bickering language. It is a matter of cold barley sandwiches and harsh opinions. Bob was nice about it, maybe someone should tell me to sh*tup:roll:
 
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