jar546
Forum Coordinator
I would like to bring this simple, everyday problem to the residential electrical inspector side of our group. We are in the middle of a voltage drop (Vd) discussion on the commercial side so I thought this would be appropriate and a learning tool for the residential only electrical inspectors. I really hope that we learn from this and that we have good discussion and some takers for something that we should all now how to do. I first learned this in 1987 but the code has changed since then and Vd has been demoted to an FPN in the NEC. Here it goes.
You have received a permit for a homeowner who wants to install an exhaust fan in his accessory pole barn that he uses to store his personal classic car collection. There is currently no electricity at the pole barn and he just wants an exhaust fan as there is plenty of ambient light when he is there during the day. (don't look into this too much). He is proposing to run PVC conduit underground in a trench for the single 120v circuit from the house to the pole barn, a total of 120' from the main service panel. Taking the FPN into account with a maximum 3% Vd for this branch circuit, what is the minimum size THWN copper wire he will need?
Here is a photo of the nameplate for the motor he will be installing:
A few things about answering this question:
1) We would like to see your answer and how you got that answer.
2) Assume a permit is required, your local conditions not a factor, this is a simple, straightforward question.
3) Telling them they have to go to an engineer is not acceptable.
4) Let us please have some fun with this and learn.
If you need any other info I will give it to you.
Have at it!!
You have received a permit for a homeowner who wants to install an exhaust fan in his accessory pole barn that he uses to store his personal classic car collection. There is currently no electricity at the pole barn and he just wants an exhaust fan as there is plenty of ambient light when he is there during the day. (don't look into this too much). He is proposing to run PVC conduit underground in a trench for the single 120v circuit from the house to the pole barn, a total of 120' from the main service panel. Taking the FPN into account with a maximum 3% Vd for this branch circuit, what is the minimum size THWN copper wire he will need?
Here is a photo of the nameplate for the motor he will be installing:
A few things about answering this question:
1) We would like to see your answer and how you got that answer.
2) Assume a permit is required, your local conditions not a factor, this is a simple, straightforward question.
3) Telling them they have to go to an engineer is not acceptable.
4) Let us please have some fun with this and learn.
If you need any other info I will give it to you.
Have at it!!