Basic Electricity

Wire Wire consists of: A conductor Insulation Copper (CU) Copper-clad aluminum Insulation Materials are based on the specific application Designed to be non-conductive

Wire and Fuse Sizing Max fuse size Minimum Circuit Ampacity (MCA) Ground Voltage drop National Electric Code (NEC)

Wire and Fuse Sizing High and low voltage wire not allowed in same conduit Conductor or wire sizing is necessary to allow enough current to flow Sized by: American Wire Gauge (AWG) Amount of amperage permitted to carry Types most commonly used: THHN TW

Fuses and Circuit Breakers • A fuse is the simplest form of circuit protection. The word fuse derives from the Latin word meaning “to melt” • Fuses have been used almost since electricity’s beginning. The earliest type of fuse that was used was a simple bare wire that was smaller than the conductor it was protecting, and therefore would melt before the conductor was harmed Fuse Symbols Screw-in style fuse Cartridge Fuse

Circuit Protection Purpose of circuit protection: 1. To protect the circuit wiring 2. To protect the loads within the circuit Protection from what: 1. Direct shorts 2. Excessive heat 3. Excessive current If these concerns are not protected, the possibilities are endless: fires, deaths, etc., which makes this issue a priority

Ratings Fuse Ratings Current Rating Voltage Ratings Time Delay Rating Standard

Circuit Breakers It is called a circuit breaker because it breaks (opens) the circuit. The first compact, workable circuit breaker was developed in 1923. In 1928 the first circuit breaker was placed on the market.

Typical Residential Receptacles

Typical Romex Nomenclature When wiring goes through a metal opening, it should be protected from wear by the use of plastic grommets, Romex connectors, or conduit connectors. Number of insulated wires Cable type Max. Voltage Rating Paper Wire Gauge

Typical Romex Nomenclature Electrical boxes, furnaces, condensers, and disconnects all need connectors on high and low voltage wire to protect and to secure it Locknut Cable Clamp Cable Sheathing

Wiring 120 Volt Wiring (1) Black wire (Hot) potential (1) White wire (Neutral) potential (1) Bare or Green wire (Ground) safety! 240 Volt Wiring (2) Black wires (Hot) (1) Black (1) Red wire (Hot) (1) Bare or Green wire (Ground) safety 240 VOLT If using Romex with a Black and White wire, tape the white insulation with black electrical tape to mark it as a hot wire.

When installing wires to switches, receptacles, thermostats, etc When installing wires to switches, receptacles, thermostats, etc., loop the wire slightly and install the loop in the direction you will tighten screw. Only strip back wire enough to make a good connection. Leaving extra bare wire is dangerous!

Duplex Receptacle Switch turns receptacle on and off Receptacle stays hot. Switch turns appliance on and off

Split bolts can be used to join multiple high voltage wires. Wire Nut and Split Bolt High voltage wiring can be spliced together with split bolts or wire nuts. Split bolts can be used to join multiple high voltage wires.

Typical Pictorial Diagram of a Condenser Wires must be in conduit Conduit must have connectors on both ends Conduit must be strapped or supported Try to run conduit straight and at 90 degree angles

Low Voltage Components The air conditioning system is comprised of high voltage and low voltage circuits What is a transformer?

Thermostats Air Conditioner Heat Pump Thermostat Heater Condenser Thermostat Indoor Unit Outdoor unit

Color Code For Low Voltage Thermostat Wiring

Color Code For Low Voltage Thermostat Wiring

Relays A relay is a device where current going into a coil creates a magnetic effect, which switches one or more sets of contacts Different types of relays: Control duty relays Fan duty relays Contactor relays There are 4 items you need to know about a relay or contactor: Coil voltage Contact voltage (maximum) Contact amperage (maximum) Contact type (S.P.S.T.; S.P.D.T.)

Fan Center Fan Center is a fancy name for a transformer and fan relay mounted on a 4 x 4 cover plate that can be easily attached to a 4 x 4 gang box They are primarily used with furnaces that were designed as heating-only systems (both gas and oil) that are being converted for use with air-conditioning There is typically a wiring diagram available on the fan center