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Advancement and Development of Electricity and Technology
Building Integrated PV
Bypass diodes
Determining low temperature that caused the inverter to go over voltage
Another NABCEP PVIP Certificate in the mail!

Most Popular Posts

Feeder PV Connections 705.12(D)(2)(1)(b)
Crimping MC4 Connectors without the tool
Converting kWh to pounds of CO2
NEC 310.15(A)(2) Exception, 10% or 10 feet or less for sizing conductors
PV Temperature coeficcients in V/C, mV/C and %/C with conversion examples

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Advanced PV Course
NABCEP PV Installation Professional Exam Prep Course
NABCEP PV Technical Sales Exam Study Group (which will evolve into a full course)
PV Boot Camp and NABCEP Entry Level Exam Prep Course
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HeatSpring PV Course Blog

NABCEP PV Installation Professional Exam Prep Course

Another NABCEP PVIP Certificate in the mail!

Post NABCEP PV Installation Professional Exam Comment

Thanks for a really good prep class, Sean and Heatspring! I also got my certificate on the first try.

A:

That is excellent that you passed the NABCEP PVIP!! Glad to help!

Thanks for the feedback,

Sean White

Post NABCEP PV Installation Professional Exam Comment

NABCEP PV Installation Professional Exam Results

Post NABCEP PV Installation Professional Exam Comment

Dr. White, I received my certificate today! Thanks so much for the great course, I will definitely recommend it to others who are prepping for the exam.

A:

That's great! Congratulations!!

Post NABCEP PV Installation Professional Exam Comment

NABCEP PV Installation Professional Exam Happy Camper!

Post NABCEP PV Installation Professional Exam Comment

Hello Sean,
I passed the exam. I got the certification yesterday. I am so happy I passed it first time trying. Your class was a great help.
Thank you so much!

A:

Congratulations!!

Post NABCEP PV Installation Professional Exam Comment

Post NABCEP PV Installation Professional Exam Comment

NABCEP PV Installation Professional Exam Prep Course Discussion Board from HeatSpring Course

Post exam comment:

Hi Sean,
I did it. I think I can pass. Thanks for your help. I am glad I got this training. It helped me a lot. I think it would have been impossible if i haven't taken this course.
Yesterday, during the exam, I don't think there was any thing related to rapid shutdown, or feeders and taps.
There was one question about sub panel connection.

One of the questions is on the Sample of Nabcep Exam from NABCEP study guide.

Maximum Number of Strings on a Combiner Calculation


Q:

I am having trouble grasping an outside sourced practice question:
A 225 kW(DC) commercial system with a single 225 kW(AC) central inverter is being installed. The module specifications are:
Maximum power (Pmax): 200 W
Voltage at maximum power (Vmp): 28.9 V
Current at maximum power (Imp): 6.93 A
Open-circuit voltage (Voc): 36.2 V
Short-circuit current (Isc): 7.68 A
Maximum system voltage: 600 V
Maximum series fuse rating: 15 A

705.32 Ground Fault Protection


Q:

Hello Sean,
About Question 33, if the building has less than 1000amp service, can we do the load side connection on subpanel?
Thanks!

A:

The answer is no, because the subpanel is on the supply side of the of the 1000A ground fault breaker.

In the NEC it says:
705.32 Ground Fault Protection: Where ground fault protection is used, the output of an interactive system shall be connected to the supply side of the ground fault protection.

310.15(B)(3)(a) Derating and not counting the Equipment Grounding Conductor or When not to Count the Neutral

NABCEP PV Installation Professional Exam Prep Course Discussion Board from HeatSpring Course

Q:

on question 52, looking at the derating part for the number of conductors in the conduit on table 310.15b3a we have two source circuits which is 4 conductors plus an equipment grounding conductor. The table shows 4 to 6 which at the end of the day the derating would be the same for 4 or 5 but you only consider 4. Could you explain why you don't count the 5th equipment ground conductor?? The footnote states the count shall not include conductors that that are connected to electrical components but cannot be simultaneously energized.

9 days until the NABCEP Exam Date! Advice


9 days until exam date!!

Now is the time to dive into the exam questions that we have here and to not procrastinate. The NABCEP PVIP Exam is famously difficult, which is why NABCEP Certificates are known as being the top of the field. Pass this exam and your salary will triple in 3 years, guaranteed! (It happened to me).

I recommend not getting overly concerned with anything obscure and especially not searching for answers on facebook.

Why we use cell temperature instead of ambient temperature when calculating the short PV string size


Q:

Sean,
On Question 51 can you explain why we use the high cell temperature over the high ambient temperature?
Thanks

A:

When we are determining voltage, what is important is how hot or cold the solar cell is, not how hot or cold it is outside. That is why airflow leads to better production. BIPV has less airflow than a rooftop, which has less airflow than a ground mount, which has less airflow than a pole mount.

690.8(B) Breaker Sizing


Q:

Hello
regarding question 6 explanation. I understand how you arrived at the 20 A breaker for the 100 A busbar. I am not familiar why you then took the 20 A breaker divided by 1.2 to arrive at 16 A.

A:

A breaker has to be sized based on 125% of the current of the device (and then round up). This comes from 690.9(B) of the NEC, which states:

"Overcurrent device ratings shall be not less than 125 percent of the maximum currents calculated in 690.

What to bring to the NABCEP PVIP exam


Q:

I understand we will be give a copy of the NEC by the examiners. So what materials specifically are we allowed to bring to the exam other than the FX 260?
I have the NEFPA70 2014 binder. Do I need to get a soft back or will the copies provided be our only source?
Thanks

A:

They will supply the calculator (it is recommended to get one to practice with) and they will supply an NEC Code Book, along with pencils and paper.

NEC 310.15(A)(2) Exception, 10% or 10 feet or less for sizing conductors


Q:

I don't quite understand the Week 1, Assignments 2, Code-Compliant Conductor Sizing - Part 1 when you talk about the "10 feet or 10%" . I wonder if you can explain it more or give me an example.
Thanks!

A:

To put this in context, 310.14(A)(2) tells us:

When more than one ampacity applies to a given circuit length, the lowest value shall be used.

Then the NEC 310.15(A)(2) Exception states:

Where two different ampacities apply to adjacent portions of a circuit, the higher ampacity shall be permitted to be used beyond the point of transition, a distance equal to 10 feet or 10% of the circuit length figured at the higher ampacity, whichever is greater.
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