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To qualify as an electrode, a water pipe must be in contact with the earth for at least _____ feet.
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When using a water pipe as an electrode you must connect to it within _____ feet of where the water pipe enters the building.
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Article 250
Grounding and Bonding
| Question | Answer |
|---|---|
| To qualify as an electrode, a water pipe must be in contact with the earth for at least _____ feet. | 10' 250.52(A)(1) |
| When using a water pipe as an electrode you must connect to it within _____ feet of where the water pipe enters the building. | 5' feet 250.66(C)(1) |
| Structural steel may be used as an electrode if it is in contact with the earth for at least ______ feet. | 10' feet 250.52(A)(2) |
| A ground ring must consist of at least ______ feet of #_____ bare copper and must be buried at least _____ deep. | 20' #2 30" 250.52(A)(4) and 250.53(F) |
| A concrete encased electrode must consist of at least ____ feet of ____ inch rebar, or #_____ bare copper. | 20' feet 1/2" inch #4 250.52(A)(3) |
| A rod or pipe electrode must consist of ____ feet of at least ______ pipe or ____ inch rod unless listed or other diameters. | 8' feet 3/4 5/8" 250.52(A)(5) |
| Plate electrodes must have at least ____ square feet of surface area and must be buried at least ____" deep. | 2 square feet 30" 250.52(A)(7) 250.53(H) |
| Rod or pipe electrodes must be supplemented by another electrode UNLESS the resistance to ground is not over ____ ohms. | 25 ohms 250.53(A)(2) exc |
| If a ground rod is supplemented by another ground rod you must space them at least ____ feet apart. | 6' feet |
| The only electrode that must always be supplemented _______ ________ electrode. | water pipe 250.53(D)(2) |
| If solid rock is encountered, you may lay a ground rod down in a trench that is at least _____ deep. | 30" inch 250.53(G) |
| Underground ____ piping or ___________ ground rods may not be used as electrodes. | gas aluminum 250.52(B) |
| If using aluminum for the GROUNDING ELECTRODE CONDUCTOR it must not be terminated to the elctrode within _____ inches of the earth when outside. | 18" inches 250.64(A) |
| What size copper Grounding Electrode Conductor is required for a service that uses aluminum 800 kcmil conductors for the phases? Water pipe electrode. | 1/0 T 250.66 |
| A service uses three 4/0 copper conductors in parallel for each phase. What size copper grounding electrode conductor is required to the water pipe electrode? | Table 8 Chapter 9 4/0 = 211600 x 3 = 634,800 cm = 2/0 |
| What is the maximum size Copper Grounding Electrode Conductor ever required to be run to a water pipe no matter how large the service conductors are? | 3/0 T 250.66 |
| No matter what the service size, the largest copper Grounding Electrode Conductor ever required to a driven ground rod, pipe, or plate electrode is _______. | #6 copper AWG 250.66(A) |
| No matter what the service size, the largest copper Grounding Electrode Conductor ever required to a concrete encased electrode is __________. | #4 copper AWG 250.66(B) |
| What size copper Main Bonding Jumper is required for a service that uses 500 kcmil copper conductors for each phase? | 1/0 Table 250.102(C)(1) |
| What size copper Main Bonding Jumper is required for a service that uses six 400 kcmil copper conductors per phase? | 300 kcmil 6 x 400 kcmil = 2400 kcmil x .125 = 300 kcmil |
| Table 250.102(C)(1) is used for sizing the _________ conductor, the _____ bonding jumper, the _________ bonding jumper, and ________ _________ bonding jumpers. | grounded, main, system, supply side Table 250.102(C)(1) |
| Equipment grounding conductor sized ____ and smaller must be green or bare their entire length. | #6 250.119(A)(1) |
| Flexible metal raceway may not serve as an equipment grounding path if the total length is over _____ feet. | 6' feet 250.119(A)(1) |
| What minimum size copper equipment grounding conductor is required for a 60 amp branch circuit? | #10 Table 250.122 |
| What minimum size copper equipment grounding conductor is required for a 600 amp branch circuit? | #1 AWG Table 250.122 |
| When running conductors in parallel, must the equipment grounding conductor be installed in each parallel raceway? | yes 250.122(F) |
| When installing a service raceway, an underground metal elbow installed in a run of PVC need not be grounded as long as it is buried at least _____ inches deep. | 18" inches 250.80 ex |
| Must the equipment grounding conductor run to a pump motor also be connected to the metal well casing? | Yes, "The Earth shall not be considered as a ground fault path" |
| Frames of household ranges and dryers may only use the grounded neutral conductor for equipment grounding purposes for _______ circuits. | existing 250.140 ex |
| The grounded conductor may be used to ground exposed metal parts only on the ______ side of the service disconnect. | line 250.142 |
| If a ferrous metal raceway is used to protect the GEC, it must be bonded to the GEC at ______ end(s). | both 250. (E)(1) |
| Standard locknuts may not be used for bonding purposes at the ________. | service 250.92(B) |
| A locknut on an EMT connector is not considered to be adequate bonding if you encounter concentric knockouts AND the voltage is over ______ to ground. | 250V 250.96 |
Created by:
loran