Smitty’s Two Minute Drill Grounding and Bonding

Smitty’s Two Minute Drill Grounding and Bonding 2017-5
A drill to help you improve your code skills and your ability to find answers in the code book. © Ted “Smitty” Smith 2016, 2017

Directions Left click on the presentation ICON located at the bottom of the slide directory to the left of the this slide or in the top menu under SlideShow. Each slide will transition to the correct answer automatically in 2:00 minutes. The correct answer will transition in 5 seconds. Do not worry about writing down the correct answer for now. You will have the opportunity to do that at the end of the two minute drill Good luck. REMEMBER: To have the best effectiveness, put this presentation in slide show mode and use the timers. This will help you get to 2 minutes per question. Do no worry about the answers until you get through the timed section. Following the timed section, the slides are repeated without time so you can look them up.

Question 1 If an equipment bonding jumper on the load side of an overcurrent protective device is installed on the outside of a raceway, it shall be routed with the raceway and have a maximum length of _____________. A. 2 feet B. 4 feet C. 6 feet D. 10 feet Copyright 2017 Ted "Smitty" Smith

Question 1 Answer 250.102(D)(2) C. 6 feet
Copyright 2005 Ted "Smitty" Smith

Question 2 Size the grounding electrode conductor at a main service switch gear that is fed with service entrance conductors that are (2) parallel runs of kcmil copper. Assume all conductors are copper. A. 2/0 B. 3/0 C. 250 kCMIL D. 500 kCMIL Copyright 2005 Ted "Smitty" Smith

Question 3 The grounding electrode required at a 480V/208V Delta-Wye transformer which is a separately derived system shall be connected to: A. Structural Steel B. The water main within 5 feet C. The building’s grounding electrode system D. A ground ring Copyright 2016 Ted "Smitty" Smith

Question 4 The final connection of the grounding electrode conductor to the concrete encased grounding electrode will be buried under grade. What needs to be done at this connection? A. it needs to be installed in an accessible hand box B. it needs to be installed so that it can be accessible in the future C. it needs to be treated with PVC and sealed D. Nothing. It is allowable to have these connections buried and not accessible Copyright 2005 Ted "Smitty" Smith

Question 5 What is the minimum sized bonding jumper which will be used for the line side of an overcurrent protective device if the service entrance conductors are six (6) parallel runs of kCMIL aluminum? The bonding jumper will be copper. A. 600 kCMIL B. 300 kCMIL C. 500 kCMIL D. 750 kCMIL Copyright 2017 Ted "Smitty" Smith

Question 5 Answer 250.102(C)(1) Table Chapter 9, Table 8 A. 600 kCMIL

Question 6 Size the system bonding jumper for a separately derived system that has derived conductors sized at 1/0 Aluminum. Assume a copper system bonding jumper. A. 8 B. 6 C. 4 D. 2 Copyright 2005 Ted "Smitty" Smith

Question 6 Answer 250.30, 250.28(D) AND 250.102(C)(1) A 8

Question 7 Where a three-phase, delta-wye, 480V to 208/120V transformer supplies two separate 208V three phase panels, the system bonding jumper for each enclosure shall be sized using Table (C)(1) or a single system bonding jumper shall be installed at the source and sized based on the size of the largest supply conductor determined by the sum of the areas of the corresponding conductors of each set the size of the largest supply conductor to the panels the size of the largest supply conductors to the panels as determined by the sum of the areas of the corresponding conductors of each set None of the above Copyright 2005 Ted "Smitty" Smith

Question 8 What is objectionable current? A. Overcurrent B. Overloads
C. Faults created by ground loops D. Currents induced onto grounding conductors by the eltromagnetic force of alternating current conductors and systems. Copyright 2005 Ted "Smitty" Smith

Question 8 answer D. Currents induced onto grounding conductors by the elctromagnetic force of alternating current conductors and systems. General AC theory knowledge. It is often referred to as “noise” Copyright 2005 Ted "Smitty" Smith

Question 9 A snap switch is installed in a metal box that is connected to EMT conduit. The snap switch is mounted with metal screws. The switch has an equipment grounding conductor screw. Is an equipment grounding conductor green pigtail required to be connected to this switch. A. Yes B. No Copyright 2005 Ted "Smitty" Smith

Question 10 What is the minimum sized bonding jumper required to bond a 2” EMT raceway to a metal junction box mounted in the ceiling, 200 feet from the service, that will be used only as a pull box. The raceway contains all 30 ampere circuits all rated at 208V. The box will contain conductors rated as high as 50 amperes and all will be rated at 208V. The largest conductor will be an 8 AWG copper. A. 8 AWG B. 10 AWG C. 12 AWG D. None of the above. A bonding jumper is not required because the voltages are less than Volts to ground. Copyright 2005 Ted "Smitty" Smith

Question 11 A grounding electrode of the rod type must be installed so that at least _________ of length is in direct contact with the soil. A. 1 meter B. 2 meters C meters D meters Copyright 2005 Ted "Smitty" Smith

Question 11 answer C. 2.44 meters 250.53(G)

Question 12 What is the minimum sized equipment grounding conductor that is required for a piece of fixed equipment that is rated at 30 amperes and is fed with a 6 AWG copper conductor that is protected by a 30 ampere overcurrent protective device? All of the equipment, conductors and overcurrent devices are rated at 75 degrees Celsius. A. 10 B. 8 C. 6 D. 4 Copyright 2005 Ted "Smitty" Smith

Question 13 Which of the following circuits SHALL NOT be grounded?
A. Line side of a separately derived service B. First disconnecting means of the service C. Circuits for electric cranes operating over combustible fibers in a Class III locations Circuits feeding heavy duty lamp holders in dwelling units Copyright 2017 Ted "Smitty" Smith

Question 14 If the ungrounded service entrance conductors are installed in parallel, in separate raceways, then the grounded conductor shall be installed in each raceway and shall be sized based on the ___________________________________. A. Total circular mill area of all the ungrounded service entrance conductors B. An equal size of the ungrounded service entrance conductors C. Based on the overall circular mill area of the ungrounded service entrance conductors in each raceway or cable D. Table Copyright 2016 Ted "Smitty" Smith

Question 20 Answer 250.30, 250.28(D) AND 250.102(C)(1) C. 4

Question 21 An EMT conduit that encloses service conductors of 1/0 copper, at the main service entrance, that is installed in a metal enclosure through a hole that is drilled by the electrician will require a bonding bushing with a bonding jumper that is at least ________________________ AWG copper. A. 8 B. 6 C. 4 D. None of the above. A bonding bushing is not required in this installation. Copyright 2017 Ted "Smitty" Smith

Question 22 What is the minimum sized copper bonding jumper required for a metal raceway which contains 20 A branch circuit conductors which are fed from a service? The service is fed with 4/0 Aluminum, THHN conductors. A. 12 AWG B. 10 AWG C. 6 AWG D. 4 AWG Copyright 2005 Ted "Smitty" Smith

Question 22 answer 250.102(D) A. 12 AWG

Question 24 Size the equipment grounding conductor for a branch circuit installed in schedule 80 PVC that is protected by a 20 ampere overcurrent device. The ungrounded conductors are 10 AWG copper. A. 12 B.10 C. 8 D. 6 Copyright 2005 Ted "Smitty" Smith

Question 25 What is minimum sized grounding electrode, copper which can be used for a main service entrance that is fed with three (3) parallel runs of 300 kCMIL copper conductors? A. 2 AWG B. 1/0 AWG C. 3/0 AWG D. 250 kCMIL Copyright 2005 Ted "Smitty" Smith

Copyright 2005 Ted "Smitty" Smith
End of Drill Click on this slide to continue to the repeat of the questions. The timer will not operate in this section. Click on each slide to advance. Review the questions and look up the answers. Copyright 2005 Ted "Smitty" Smith

Question 1 If an equipment bonding jumper on the load side of an overcurrent protective device is installed on the outside of a raceway, it shall be routed with the raceway and have a maximum length of _____________. A. 2 feet B. 4 feet C. 6 feet D. 10 feet Copyright 2017 Ted "Smitty" Smith

Question 1 Answer 250.102(D)(2) C. 6 feet