Color codes. Exercise 1. Answer the questions. Exercise 2. Match the words with their definitions. Unit 3. Watt hour meters. Vocabulary

Color codes

Different color wires serve different purposes, like:

· Black: Hot wire, for switches or outlets.

· Red: Hot wire, for switch legs and for connecting wire between two hardwired smoke detectors.

· Blue and Yellow: Hot wires, pulled in conduit. Blue for 3-4 way switch application, and yellow for switch legs to control fan, lights etc.

· White: Always neutral.

· Green and Bare Copper: Only for grounding.

 

Exercise 1. Answer the questions

1. What is the difference between wire and cable?

2. What is the wire gauge?

3. What does wire lettering represent?

4. What wire type is used in service drop conductors?

5. Why are non-metallic sheath wires preferred for in-house wiring?

6. What insulation is used in non-metallic sheath wires?

7. What color is the ground wire?

Exercise 2. Match the words with their definitions

1. wire                 a) a wire which comes from the bottom terminal of the switch and becomes hot when the switch is turned on; it is used to turn the load on and off

2. cable                b) a flexible insulated electric cable, used especially to connect appliances to mains

3. cord                 c) an overhead electrical line running from a utility

pole, to a customer’s building or other premises

4. service drop    d) a flexible metallic conductor, usually insulated, used to carry electric current in a circuit

5. weatherhead    e) a grouping of two or more independent electrical wires

6. switch leg        f) a weatherproof receptacle at the service drop entry point where overhead conductors enter a building

 

Unit 3. Watt hour meters

Vocabulary

accuracy                                           точность

automatic meter reading system     система автоматизированного

снятия показаний счетчика

counter mechanism                         счетный механизм

current coil                                      обмотка тока

dial                                                   циферблат; круговая шкала

eddy current                                     вихревой ток

electromagnet                                  электромагнит

electromechanical induction meter электромеханический индукци-

онный счетчик

to exert force                                   прилагать силу

flux                                                   поток

gear train                                          зубчатая передача

high end processor                           высокопроизводительный про- цессор

instantaneous voltage                      мгновенное напряжение

to lag                                                отставать

meter                                                счетчик

metering point                                 место измерения

phase angle                                      угол сдвига фаз, фазовый угол

power line communication              ВЧ-связь по ЛЭП

pressure coil                                    обмотка напряжения

product                                             произведение, результат умноже- ния

pulse rate                                         частота повторения импульсов

smart energy meter                          интеллектуальный счетчик элек- троэнергии

spindle                                             ось, вал

utilities                                             коммунальные предприятия