Available fault current practice questions?
- Thread starter tortuga
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AC\DC
Senior Member
- Location
- Florence,Oregon,Lane
- Occupation
- EC
Are you meaning officially for Oregon Journeyman or just in general.Tom Henry "Transformer Exam calculations" has about 3-5 question of figuring Available fault current. I can post if you would like,
Yes thank you! I have a coworker that got stumped by a few on the Oregon J-man test.
letgomywago
Senior Member
- Location
- Washington state and Oregon coast
- Occupation
- residential electrician
Theres a couple examples in the ugglys book and he can bring it in with him.
Tulsa Electrician
Senior Member
- Location
- Tulsa
- Occupation
- Electrician
I'm going to look them up.
Thanks
I like to start the guys out with simple transformer impedance on a 75 KVA 480 to 120/208.
They always ask is this equipment good. I say let's find out. Then show them the time current curve of the breaker and see how it falls into the instantaneous range.
Then I remind them we need fault current to open OCPD. Bolted/line and ground fault.
Then relate that to good grounding/ bonding and ask, now how import is tightening up this connectors and couplings. Or sizing the wire type EGC correctly. Leading them into IT squared for conductor withstand ratings.
I love it when there face lights up when they get it.
A line to line and bolted fault is easy. The ground fault is when they really get it. If the wire is good and you have known resistance.
Now you bring in the ground fault and either a light bulb goes off or more training required. Starting with definition and low impedance.
The guys that get it tend to stick around and the rest go to the installer crews( shovels).
sarifritter
New User
- Location
- us
- Occupation
- engineer
It's crucial to consult the specific guidelines and requirements for the journeyman exam in your field. Many trade organizations and licensing bodies provide exam outlines and sample questions to help candidates prepare. You can also consider using textbooks, scratch geometry dash study guides, and online resources designed for your specific trade to practice and prepare for the exam effectively.
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
Not sure if I agree with knowing how to do the calculations being part of a journeyman exam. Awareness of available fault current and knowing the rules to applying equipment ratings is fine and maybe should be a question or two on this topic on the exam. Master or contractor licensing exam - maybe some more validity to having questions on calculations.
I can't even do these calculations without some reference materials, but probably haven't done such a calculation without computer assistance (typically the spreadsheet available on MH site) since I was in college about 35 years ago.
I can't even do these calculations without some reference materials, but probably haven't done such a calculation without computer assistance (typically the spreadsheet available on MH site) since I was in college about 35 years ago.
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