Cheatography
https://cheatography.com
A cheat sheet that has the most important info for the ICC E2 exam from the 2023 NEC.
This is a draft cheat sheet. It is a work in progress and is not finished yet.
Dwelling Unit Load
1- General Lighting Load SqFt. x 3va, 1st 3,000VA = 100% , 3,001va-120,000va =35%, 120,001+= 25% 220.45 |
2-Small Appliance & Laundry =4500va 220.52 |
3-Add 1&2 |
4-Heat & AC Keep larger, omit smaller. 220.60 |
5-Appliance Load 75% for 4 or more fixed appliances. 220.53 |
6-Dryer 5000va or Nameplate rating. 220.54 |
7- Demand for Cooking Equipment 8000kv between 3.5kw-12kw. Smaller use nameplate. Larger 5% per kw higher 220.55 |
8-Largest motor The largest motor is 125% of FLC. Not AC unless its larger than heat. FLC 430.248 |
Size service by Dividing the total by the voltage(240). Apply table 310.12(A) |
Size Grounding Electrode Conductor 250.66 |
Ohm's Law and Power Formulas
P = Power= Watts |
E = Force=Volts |
I = Current = Amperes |
R = Resistance + Ohms |
Ohm's Law
VOLTAGE E(volts)=I Current(AMPS) X R Resistance(ohms) |
CURRENT = Voltage ÷ Resistance |
RESISTANCE = Voltage ÷ Current |
Power Diagram & Formulas
POWER (Watts) = Current X Voltage |
VOLTAGE = Power ÷ Current |
CURRENT = Power ÷ Voltage |
3 phase
Single Phase VA=V x I |
Three-phase VA=√3 x V x I = 1.732 x V x I |
Current (Three phase) I= (VA)÷(√3 x V) |
120v = 208 __ 277v = 480 |
If the voltage is 208v 3Phase.. Divide VA x 1000 by 360 to get amps |
If the voltage is 480v 3 phase.. divide VA x 1000 by 831 to get amps |
FLA x either 360 or 831= the total VA |
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Top Tables Likely in Test
Bonding Jumper Sizing 250.102 |
Sizing main bonding jumper, system bonding jumper, and supply side bonding jumper. |
EGC Sizing 250.122 |
Sizing EGC based on rating of Ove current protective device. |
Ampacity Tables 310.15, 310.16 |
Ampacities of conductors. Demand factors for number of conductors. Temp corrections. |
Conduit and tubing fill Ch.9 Table 4 |
#of conductors in a conduit or tube. |
Conductor dimensions Ch.9 Table 5 |
Listing the dimensions, area, and resistance of insulated conductors and fixture wires. |
Conductor Resistance Ch.9 Table 8 |
Providing DC resistance values for copper and aluminum conductors. |
Branch Circuit Requirements 210.24 |
Summary of min requriements for common 10amp-50amp branch circuits |
Grounding Conductor Identification 200.6 |
Means of identifying grounded Conductors. |
Conductors for general wiring 310.4(1) |
Conductor applications and insulations rated 600 volts. |
Fast Numbers
√3 = 1.732 |
208 x 0.03 = 6.24 v max drop |
480 x 0.03 = 14.4 v max drop |
208V 3Φ current = VA ÷ 360 |
480V 3Φ current+ VA ÷ 831 |
Motor VA=208V: FLA x 360|480V: FLA x 831 |
K = 12.9 uncoated Cu (23.3) Aluminum 21.2 (36.8) |
Continuious load +1.25% |
Largest motor = +125% (branch)| +25% feeder/service |
VOLTAGE DROP
**Voltage drop = (2 or (1.732) x K x I x D) ÷ Circular Mils |
If continious multiply 1.25 to load. Then compair on 310.16 table. then do the calculaton and compare to table 8. Highest one is the answer.
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