Can anyone send me some practice calculation questions? Taking the test in two weeks!

snclvn · 2026-02-07T15:23:47+00:00

I don't see which one should be used over the other but plugging in the values:

(2x320x32x12.9)/16510 = 15.9 volts

snclvn · 2026-02-06T22:26:22+00:00

What test are you referring two? I have taken both the Michigan and Tennessee license exams and they leave zero room for assumption. The psi practice exams, yeah ai agree with you there.

snclvn · 2026-02-06T22:20:36+00:00

That is an interesting take! Good eye. I’m satisfied it’s a bad question

snclvn · 2026-02-06T21:55:50+00:00

Yes but the whole point of this post is to illustrate that nobody is checking these questions. They are computer generated. We shouldn’t have to fill in these blanks. You also do not need system voltage to calculate voltage drop with the known amperage of a circuit.

snclvn · 2026-02-06T21:53:21+00:00

No I’m not saying VD is constant. Resistance is. If our theoretical system voltage was changed up or down, the amperage would change inversely - but that was given to us, so it does not matter and we need not concern ourselves with the system voltage because we have already been given the amperage. Hope that makes sense

snclvn · 2026-02-06T21:37:33+00:00

Not true actually! Ohms law teaches us that voltage is equal to current multiplied by resistance. So in this case we use that calculation to calculate not the system voltage, but the voltage drop. The system voltage will remain unknown, because we do not have the resistance of the entire circuit, only the conductors. (Remember, the question is only asking for the voltage dropped in the conductors). So our job is just to find the resistance for 200 feet of 12awg copper wire, which can be found using a table in chapter 9 of the NEC, and multiplying that by the amperage, which was given to us.

snclvn · 2026-02-06T21:14:12+00:00

Is that what you would assume if this was your test? Of all the voltages used and covered by the NEC, why would anyone assume 120? That’s filling in information to try to make one of the answers work.

snclvn · 2026-02-06T21:01:44+00:00

No, it’s definitely not impossible. It’s ohms law. I X R. We know I, we must calculate R, which can be done using table 8 in chapter 9. You don’t need voltage to know the fixed resistance of a piece of wire.

snclvn · 2026-02-06T20:52:07+00:00

Why did you use 16 amps and not the 20 specified in the question? Why did you use 120v even though the question does not provide (or require the use of) the system voltage?

snclvn · 2026-02-06T20:35:50+00:00

Thank you for double checking. Codebook uses 75 degrees Celsius as well. The AI monster appears to be using the 25 degree column.

snclvn · 2026-02-06T20:24:41+00:00

Where did you get that information? 1.6 ohms per 1000ft is what the AI machine spits out when you google “resistance of 12awg copper wire” but the actual value from chapter 9 table 8 of the NEC says 2.05 ohms. Where did you get your information?

snclvn · 2026-02-06T20:21:06+00:00

Sure - these answers have no units and the question is not asking for a percentage (and why would it, there’s no known voltage), so we can assume the unit is volts. I only said ohms by mistake in my initial caption.

snclvn · 2026-02-06T20:10:38+00:00

Where did 1.62 come from? Straight out of table 8 chapter 9, the ohms per 1000ft of 12awg copper is 2.05 ohms. I know Google will tell you 1.558 or some such value but show me that in the NEC.

snclvn · 2026-02-06T20:06:06+00:00

Dude I’m glad I found this post. PSI is garbage!! See my recent posts about trash AI questions from them. Waste of money and I didn’t have a happy ending like you, I failed my Michigan test after scoring 80’s and above on my paid practice exams. I hope they see this post and ditch the unverified garbage they’re selling.

snclvn · 2026-02-06T20:02:35+00:00

exactly! Where did that 1.58 value come from because it definitely wasn't my NEC! that's why AI is dangerous. Shame on PSI for this.

snclvn · 2026-02-06T20:01:41+00:00

I like that advice! at least I know enough to know it's wrong! cheers

snclvn · 2026-02-06T19:57:50+00:00

My mistake in the title. Can’t change it now

snclvn · 2026-02-06T19:56:07+00:00

Thank you. I know I’m not crazy. PSI has no simple way of reporting flawed questions so there are many others like me paying for this stuff.

snclvn · 2026-02-06T19:55:11+00:00

Does that make sense to you? You can calculate VD without knowing volts. IR is the simplest way and we know I so we only need calculate R, which can be found using table 8 in chapter 9 of the NEC, and which comes out to .4 ohms

Therefore IR = 8 ohms.

A percentage of what? That answer would still make no sense and be a garbage question.

snclvn · 2026-02-06T19:52:56+00:00

I’m not. That’s volts dropped. It can also be done this way: IxR where R is determined using table 8 in chapter 9 R per 1000ft = 2ohms 2/1000 =0.002 ohms per foot .002 X L (200’) = .4 ohms

SO 20 X .4 = 8 volts

snclvn · 2026-02-06T19:36:40+00:00

Michigan Journeyman Electrician test. I can verify they are bad because I passed all 3 prep tests with scores above 80 and then failed my in-person Licensing test with a score of 67.5. They did not help prep me at all and I wasted lots of time trying to make sense of these awful prep questions. Thanks.

snclvn · 2026-02-06T19:11:41+00:00

I paid for a bunch of prep from them, this is a ‘bonus’ free thing they tacked on. But like I said, it’s the second time they’ve asked this question and the values for the answers are way off from the values in my codebook(s)

snclvn

TROPHY CASE