Electricity and Safety
Marijuana Horticulture
by Jorge Cervantes
You don’t need to understand the basics of electricity to grow indoors or in a greenhouse, but understanding the basics will save you money, time, and possibly the shock of your life.
Before you touch anything electrical, please remember to work backwards when installing electrical components or doing wiring. Start at the bulb, and work towards the plug-in. Always plug in the cord last!
Ampere (amp) – is the measure of electricity in motion. Electricity can be looked at in absolute terms of measurement just as water can. A gallon is an absolute measure of a portion of water; a coulcomb is an absolute measure of a portion of electricity. Water in motion is measured in gallons per second, and electricity in motion is measured in coulombs per second. When an electrical current flows at one coulomb per second, we say it has one ampere.
Breaker Switch – ON / OFF safety switch that will turn electricity OFF when the circuit is overloaded. Look for breaker switches in the breaker panel or breaker box.
Circuit – the circular path that electricity travels. if this path is interrupted, the power will go off. If this circuit is given a chance, it will travel a circular route through your body!
Conductor – something that is able to carry electricity easily. Copper, steel, water, and your body are good electrical conductors.
Fuse – Electrical safety device consisting of a fusible metal that melts and interrupts the circuit when overloaded. Never replace fuses with pennies or aluminum foil! They will not melt and interrupt the circuit when overloaded. This is an easy way t start a fire.
Ground – means to connect electricity to the ground or earth for safety. If a circuit is properly grounded and the electricity travels somewhere it is not supposed to, it will go via the ground wire into the ground and be rendered harmless. Electricity will travel the path f least resistance. This path must be along the ground wire.
The ground is formed by a wire (usually green, brown, or bare copper) that runs parallel to the circuit and is attached to a metal ground stake. Metal water and sewer pipes also serve as excellent conductors for the ground. Water pipes conduct electricity well and are all in good contact with the ground. The entire system, pipes, copper wire, and metal ground stake conduct any misplaced electricity safely into the ground.
The ground wire is the third wire with the big round prong. The ground runs through the ballast all the ay t the hod. High intensity discharge systems must have a ground that runs a continual path from the socket through the ballast to the main fuse box, then to the house ground.
GFI – Ground Fault Interrupt outlets are required anywhere water is used in a home or business. Install GFI outlets in grow rooms to provide an instant, safe, electrical shut off when necessary.
Hertz – Irregular fluctuations or cycles in electricity within a conductor (wire). In the United States, electricity runs at 60 hertz (Hz), or cycles, per second.
Ohm’s Power Law – a law that expresses the strength of an electric current: colts x amperes = watts.
Short Circuit – A short or unintentional circuit formed when conductors (wires) cross. A short circuit will normally blow fuses and turn off breaker witches.
Volts – Electricity is under pressure or electrical potential. This pressure is measured in volts. Most home wiring is under the pressure of approximately 120 or 240 volts.
Watts – are a measure of work. Watts measure the amount of electricity flowering in a wire. When amperes, (units of electricity per second) are multiplied by volts (pressure), we get watts. 1000 watts = 1 kilowatt.
A halide lamp that draws about 9.2 amperes x 120 volts = 1104 watts. Remember Ohm’s Power Law: amps x watts = volts. This is strange; the answer was supposed to be 1000 watts. What is wrong? The electricity flows through the ballast, which uses energy to run. The energy drawn by the ballast must amount to 104 watts.
Watt-hours – measure the amount of watts that are used during an hour. One watt-hour is equal to one watt used for one hour. A kilowatt-hour (kWh) is 1000 watt-hours. A 1000-watt HID will use roughly one kilowatt per hour, and the ballast will use about 100 watts. Electrical bills are charged out in kWh.
Electrical wire comes in many thicknesses (gauges) indicated by number. Higher numbers indicate smaller wire and lower numbers indicate larger wire. Most household circuits are connected with 14-gauge wire. Wire thickness is important for two reasons – ampacity and voltage drop. Ampacity is the amount f amperes a wire is able to carry safely. Electricity flowing thru wire creates heat. The more amps flowing, the more heat created. Heat is wasted power. Avoid wasting power by using the proper thickness of well-insulated wire with grounded wire connection.
Using too small of a wire forces too much power through wire, which causes voltage drop. Voltage (pressure) is lost in the wire. A lamp designed to work at 120 volts that only receives 108 volts would produce only 70 percent of the normal light. Use at least 14-gauge wire for any extension cords, and if the cord is to carry power over 60 feet, use 12 gauge wire.
Plugs and outlets must have a solid connection. If they are jostled around and the electricity is allowed to jump, electricity is lost in the form of heat; the prongs will burn, and a fire could result. Periodically check plugs and outlets to ensure they have a slid connection.
If installing a new circuit or breaker box, hire an electrician or purchase Wiring Simplified by H.P. Richter and W.C. Schwan. it costs about $10 and is available at most hardware stores in the USA. Installing a new circuit in a breaker bx is very easy, but installing another fuse in a fuse box is more complex. Before trying anything of this scope, read about it, and discuss it with several professionals.