The Electrical Contractor Network

ECN Electrical Forum
Discussion Forums for Electricians, Inspectors and Related Professionals

Books, Tools and Test Equipment for Electrical and Construction Trades

Register Now!

Register Now!

We want your input!

Featured:
   

2017 NEC and Related
2017 NEC
Now Available!

   
Recent Posts
Industrail Control Panel bonding per 409.108
by sparkyinak
Yesterday at 03:17 PM
Calling all Non-US members!! (Non-US only)
by aussie240
12/07/16 02:39 AM
Photo Upload Tutorial
by DanK
12/06/16 11:35 PM
Sprinklered equipment 26-008
by bigpapa
12/02/16 04:24 PM
On Delay Relay with Auto Reset
by Potseal
12/01/16 09:59 AM
New in the Gallery:
12.5A through 0.75mm˛ flex (just out of curiosity)
Shout Box

Top Posters (30 Days)
gfretwell 13
HotLine1 9
Texas_Ranger 8
sparkyinak 8
Trumpy 6
Who's Online
0 registered (), 261 Guests and 5 Spiders online.
Key: Admin, Global Mod, Mod
Page 1 of 3 1 2 3 >
Topic Options
Rate This Topic
#57088 - 10/04/05 08:31 PM Class stumped?
wv-wire-wrangler Offline
Member

Registered: 09/12/05
Posts: 26
Loc: Morgantown, WV
Hi all,

I just got home from my journeyman class and we were given a practice test that the whole class checked together. One question had an answer that kinda half stumped the class, including the teacher.

Here it is:

Which are the three basic electrical faults?

a) Ground fault, partial ground fault, and open circuit.

b) short circuit, open circuit, and change in electrical value.

c) open circuit, incomplete circuit, and ground fault.

d)short circuit , ground fault, and partial ground fault.

The test writing program the teacher uses said the answer is (D), but what is a partial ground fault? Even our teacher has never heard of one!

Sam

[This message has been edited by wv-wire-wrangler (edited 10-04-2005).]
_________________________
Samuel A Mercure

Top
Work Gear for Electricians and the Trades

Work Gear for Electricians and the Trades
Work Gear for Electricians and the Trades
Arc Flash Clothing, Gloves, KneePads, Tool Belts, Pouches, Tool Carriers, etc. etc....

#57089 - 10/04/05 08:39 PM Re: Class stumped?
dmattox Offline
Member

Registered: 10/20/04
Posts: 267
Loc: Anaheim, CA
A partial ground fault would be a fault to ground not at full potential, such as in a motor winding.

Top
#57090 - 10/04/05 08:42 PM Re: Class stumped?
jw electric Offline
Member

Registered: 09/08/05
Posts: 108
Loc: Asheboro, NC
Could it be where there is an accident? Some one stepped into a hole in the ground. Would that be a partial ground fault? I mean if the ground didn’t have the hole then the accident would not have happened.

Of course it will be hard to find a lawyer that will try to sue the ground no matter how much it was at fault.
_________________________
Mike

Top
#57091 - 10/04/05 08:48 PM Re: Class stumped?
wv-wire-wrangler Offline
Member

Registered: 09/12/05
Posts: 26
Loc: Morgantown, WV
Hey JW,

GOod one. Had me laughing for a good 5 minutes!!!
_________________________
Samuel A Mercure

Top
#57092 - 10/04/05 10:32 PM Re: Class stumped?
gfretwell Offline

Member

Registered: 07/20/04
Posts: 9045
Loc: Estero,Fl,usa
A partial ground fault is one that trips a GFCI but not the O/C device.
That may be the hardest one to find.
_________________________
Greg Fretwell

Top
#57093 - 10/05/05 04:08 AM Re: Class stumped?
IanR Offline
Member

Registered: 12/06/04
Posts: 326
Loc: Palm Bay FL USA
I like JW's explanation. However on what grounds(partial grounds?)are you basing that explanation.

Top
#57094 - 10/05/05 04:15 AM Re: Class stumped?
WFO Offline
Member

Registered: 09/03/05
Posts: 206
Loc: Cat Spring, TX
Seems like an strange question, since a ground and partial ground fault are both types of short circuits.
A partial ground would probably be a high impedance ground, often one that doesn't pull enough current to activate a protective device (like gfretwell said).
A good example would be high voltage line falling on dry sand. The sand (basically glass) is such a high impedance that the line never trips. That's why you never see a lineman touch a downed wire without grounding it.

Top
#57095 - 10/05/05 04:35 AM Re: Class stumped?
Ron Offline
Member

Registered: 03/13/02
Posts: 577
Loc: White Plains, NY
If it were are fill in the blank question, I would have answered 3 phase fault, line-ground fault and 3 phase arcing fault (high impedance fault)

Other flavors would be line-line fault, line-line arcing fault and line-ground arcing fault.

So maybe according to that author, a partial fault is an arcing fault.
_________________________
Ron

Top
#57096 - 10/05/05 04:56 AM Re: Class stumped?
George Corron Offline
Member

Registered: 05/16/01
Posts: 728
Loc: Lorton, Va USA
I don't like the question either, BUT....

A partial ground fault is one most often on a high line (distribution or transmission levels) where you have an arc to ground, way to small to cause an interruption current.

What is does cause is RFI, TVI, etc. In Other Words, a ground fault NOT at interruption levels that uses power, and causes customer problems.

Top
#57097 - 10/05/05 07:49 AM Re: Class stumped?
CTwireman Offline
Member

Registered: 02/07/02
Posts: 839
Loc: Connecticut, USA
I disagree with this question entirely. There are only 2 basic types of faults, shorts and opens.

You can then get more specific and subdivide both of those categories, such as ground faults, line to line faults, etc.

But "partial ground faults?" That is very vague and confusing in my opinion.

Peter
_________________________
Peter

Top
Page 1 of 3 1 2 3 >



ECN Electrical Forums - sponsored by Electrical Contractor Network - Electrical and Code Related Discussion for Electrical Contractors, Electricians, Inspectors, Instructors, Engineers and other related Professionals